The presented research aims to clarify the specific effect of the individual components of concrete with Portland cement CEM I 42.5 R on the volume changes of concrete. The effect of the filler component was evaluated from the point of view of the composition and type of aggregate (crushed versus mined) and from the point of view of the mineralogical composition of the aggregate. Concrete formulas with a maximum aggregate grain size of 16 and 22 mm were assessed. The effect of the binder component on the shrinkage of the concrete was monitored on the concrete mixtures produced using the same aggregate and maintaining the same strength class of concrete, C 45/55. The effect of the addition of finely ground limestone, finely ground granulated blast furnace slag and coal high-temperature fly ash was monitored. It was found that the maximum aggregate grain and the type of grading curve do not have a significant effect on the volume changes of concrete. Concretes with mined aggregates showed lower shrinkage than concretes with crushed aggregates. The most significant is the effect of the type of aggregate on the volume changes in the first 24 h. Mineral additives have a positive effect on the elimination of the volume changes of concrete, while the addition of high-temperature fly ash proved to be the most suitable.  The widespread usage of concrete around the world is mainly due to its excellent formability in the fresh state and its good mechanical parameters and durability in its hardened state. However, the resulting mechanical parameters and durability of the concrete composite are affected by its microstructure without signs of micro-defects. One of the most common micro-defects of cement composite is the formation of micro-cracks due to excessive volume changes and the production of hydrating heat. Thus, it can be said that the good mechanical resistance and the resulting durability of the concrete composite depends on its hydration processes and the volume changes that have taken place during this hydration .The resuThe volume changes of the concrete composite can be divided into several stages, which follow each other or overlap ,5. In geThe highest part of the total volume changes of the concrete composite, according to the performed studies, falls on shrinkage due to drying ,15,16. TAlthough a number of studies have dealt with the impact of the type of used aggregate and its grading curve on the volume changes of the composite, it is not possible to clearly determine the intersection of the obtained results. Some research provides a picture of the suitability of crushed aggregates, which can have a positive effect on volume changes in the composite. Others have favored the use of quality mined aggregates, which can achieve a comparable degree of consistency through a lower dose of water and a lower amount of fine fractions. This theory generally applies, especially to the higher degrees of the consistency of fresh concrete, which is a trend in ready-mixed concrete today, and it relies on the theory of a lower specific surface of mined aggregate grains with a spherical grain shape compared to crushed aggregates. This fact results in a lower required dose of water for wetting the surface of aggregate grains. This statement is supported by the research of Polat et al. , where 4The presented research aims to clarify the specific effect of the individual components of concrete with Portland cement CEM I 42.5 R on the volume changes of concrete. The article is divided into two parts. The first part solves the influence of different types of aggregates on the shrinkage of concrete. The effect of the filler component was evaluated from the point of view of the composition and type of aggregate (crushed versus mined) and from the point of view of the mineralogical composition of the aggregate. Concretes with different mineral aggregate type—psammite, quartz, amphibole and granodiorite—were compared. Concrete formulas with a maximum aggregate grain size of 16 and 22 mm were assessed. When crushed and mined, aggregates were used, and the concretes were monitored, which showed the same grading curve of the aggregate mixture. The second part of the study is directly related to the first part, and it is devoted to the influence of binders on the shrinkage of concrete. The effect of the binder component on the shrinkage of the concrete was monitored on the concrete mixtures produced using the same aggregate and maintaining the same strength class of concrete, C 45/55. The effect of the addition of finely ground limestone, finely ground granulated blast furnace slag and coal high-temperature fly ash was monitored.The innovativeness and usefulness of this study is seen in the complexity of the solution of this experiment, which in the second part deals with the influence of aggregates and subsequently the influence of mineral admixtures on the shrinkage of concrete. Another significant benefit or novelty is focused on the possibility of measuring volume changes immediately from the fresh state. The results presented in this experiment demonstrate that most of the volume changes take place in the fresh state, which is in conflict with some standardization methods, which consider the beginning of measurement to measurement after gaining handling strength from 1 day of age. If the initial shrinkage is not captured, the results of volume changes may differ significantly, which may affect the final similarity of concrete structures. We consider this fact to be especially important from the point of view of concreting, for example, large expansion units, where the architect’s requirement for minimal volume changes is increasingly being taken into account today.Aggregate forms a filler component in concrete and occupies the largest part of its volume, namely 70% to 80% . Althougmax 16 mm and Dmax 22 mm, were assessed [In the performed experiment, the effect of the type of grading curve (continuous versus discontinuous) and the effect of the maximum aggregate grain, specifically Dassessed .Furthermore, the effect of the used type of aggregate was evaluated in terms of its production (mined versus crushed) in relation to its mineralogy and physical-mechanical parameters.For the evidence and practical application of this experiment, a total of four formulas with different mined aggregates and four formulas with different crushed aggregates were produced. The selection of individual aggregates was based on the portfolio of the most common types of aggregates based on their origin and occurrence in the Czech Republic. Within the mined aggregates, excavated sedimentary psammitic rock  and sedimentary rock extracted from water, mostly of the quartz type with an additive of quartzite and marl , were selected. Furthermore, natural crushed aggregate of the deep igneous amphibolite rock type  and metamorphic rock of the granodiorite type  were used. All aggregates meet the requirements of the standards for aggregates for concrete production according to EN 12620 + A1 and EN 13242 for aggregates for civil engineering and infrastructure ,31. The The individual types of aggregates and their shapes are shown in Psammitic mined rock—PMQuartz mined rock—QCrushed amphibolite rock—AMCrushed granodiorite rock—GRFor the other parts of the experiment, the following markings of the individual types of aggregates are introduced:From the photographs of the grain shape and the determination of the grain shape by the shape index test, it is clear that there is a significant difference between mined and crushed aggregates in general. From this point of view, it can be concluded that the used crushed aggregates reach a significantly higher specific surface than the mined aggregates, and higher doses of mixing water will be needed to moisten. It can be assumed that this fact will be most evident in concrete mixtures where crushed fine aggregate of the amphibolite type will be used. Although the usability of this fraction of crushed aggregate for the production of standard ready-mixed concretes is practically negligible, the possibility of its higher use and the impact of its use on the volume changes of concrete will be verified within the performed experiment.The higher specific surface of the aggregate grain, which can be easily quantified for conventional natural aggregates by a shape index value , creates a larger area for incorporating the aggregate grain into cement stone . HoweverFurthermore, based on the results given in To determine the effect of aggregate on the volume changes of concrete, a total of eight formulas were designed in accordance with the EN 206+A1 standard . All conIn the experiment, four concrete mixtures with a continuous grading curve and a maximum grain size of 16 mm and another four concrete mixtures with a discontinuous grading curve and a maximum grain size of 22 mm were designed, omitting the 4–8 mm aggregate fraction. The individual formulas differ from each other in the type of aggregate used.max 16 mm—fraction 0–4 (PM), 4–8 (PM) and 8–16 mm (PM)M-PM with Dmax 22 mm—fraction 0–4 (PM), 8–16 (PM) and 16–22 mm (PM)M-PM with Dmax 16 mm—fraction 0–4 (PM), 4–8 (Q) and 8–16 mm (Q)M-PMQ with Dmax 22 mm—fraction 0–4 (PM), 8–16 (Q) and 11–22 mm (Q)M-PMQ with Dmax 16 mm—fraction 0–4 (PM), 0–4 (AM), 4–8 (AM) and 8–16 mm (AM)C-PMAM with Dmax 22 mm—fraction 0–4 (PM), 0–4 (AM), 8–16 (AM) and 11–22 mm (AM)C-PMAM with Dmax 16 mm—fraction 0–4 (PM), 4–8 (GR) and 8–16 mm (GR)C-PMGR with Dmax 22 mm—fraction 0–4 (PM), 8–16 (GR) and 11–22 mm (GR)C-PMGR with DThe following mixtures of aggregates were used in the performed experimental measurements:The letter M in front of the mixture indicates the mixture with mined aggregate, and the letter C indicates the mixture with crushed aggregate.max 16 and with a discontinuous grading curve and Dmax 22, the effort was to achieve the same grading curve. These grading curves are shown in For all mixtures of aggregates with a continuous grading curve and DAll the concrete mixtures were produced using a constant amount of Portland cement CEM I 42.5 R from the company Heidelberg Cement, cement plant Mokra, Czech Republic. The total calculation of the composition of the concrete mixture is based on the equation of absolute volumes, and the amount of water and superplasticizer is chosen with regard to achieving the workability of a fresh concrete mixture using a slump cone test for class S4 according to EN 12350-2 . A superIn following part of the experiment, connections between commonly used mineral additives in the middle Europe and volume changes of the composite will be sought. Today’s concrete technology is strongly focused on the use of additives directly in the concrete plants or as part of mixed cements. According to the EN 206 + A1 standard, additives can be divided into two types: an inert additive of type I and an additive with pozzolanic or latent hydraulic capability type II. The use of additives to produce concrete is not only given by the economic aspect, most additives are also used to positively influence selected properties of fresh or hardened concrete. The experiment will study the effect of the most commonly used inert and active additives on the volume changes of concrete. It is known to use certain types of additives, such as high-temperature fly ash, to dissolve the development of hydration temperatures in massive structures. For these types of additives, their positive impact on the resulting volume changes of the composite can also be expected. This theory is based mainly on a slower course of hydration processes and a possible reduction in the dose of the main binder component, Portland cement, while maintaining comparable mechanical parameters of concrete ,40.Very finely ground limestone—locality MokraVery finely ground granulated blast furnace slag—locality DetmaroviceCoal high-temperature fly ash—locality DetmaroviceThe following mineral additives originating from the production of producers available in the Czech Republic were selected for the experiment:The basic mechanical and physical parameters, such as the efficiency index, the specific surface and loss on ignition, were determined for the mineral additives used, and the percentage of basic oxides was determined by XRF . All these parameters are shown in The determined efficiency index was performed by replacing 25% by weight of the Portland cement with the given additive. The results show significant activity of the blast furnace slag, but they also point to the partial activity of finely ground limestone, which from the point of view of legislation is considered an inert additive of type I. These results for very finely ground limestone agree with some published studies, which attribute to it a hidden activity in the sense of the formation of crystallization seeds during the hydration of the cement ,42.As part of the further verification of the effect of the used aggregate type (mined versus crushed), all the formulas designed for this experiment were always made with a discontinuous grading curve and Dmax 22 mm with mined quartz aggregate  and crushed granodiorite aggregate  shown in max 22 mm—fraction 0–4 (PM), 8–16 (Q) and 11–22 mm (Q)M-PMPQ with Dmax 22 mm—fraction 0–4 (PM), 8–16 (GR) and 11–22 mm (GR).C-PMGR with DPortland cement CEM I 42.5 R from the manufacturer Heidelberg Cement in Mokra and superplasticizing additives from the company MC Bauchemie PowerFlow 2695  were also used in this part of the experiment. The following mixtures of aggregates were used in this experiment:For the produced concretes in their fresh state, their density was determined according to EN 12350-6  and the Density of hardened concrete after 7 and 28 days according to EN 12390-7 Compressive strength  after 7 and 28 days according to EN 12390-3 Flexural strength  after 7 and 28 days according to EN 12390-5 Water absorption after 7 and 28 days according to CSN 73 1316 Water tightness HV8 after 7 and 28 days according to TKP RVC CR The main part of both experiments was to determine the volume changes of the concretes produced. This determination was carried out immediately from the fresh state to the age of 28 days in case of different types of aggregates and the age of 60 days in case of mineral admixtures. The measurement was determined by using special molds with a U-shaped cross-section and dimensions of 100 mm × 60 mm × 1000 mm (width × height × length). These molds from Schleibinger Geräte’s company —shrinkage drain—have a sliding face, which is firmly connected to the concrete mixture through a concreted steel anchor, and the shrinkage of the concrete is thus manifested by the forced displacement of this face. A strain gauge sensor is attached to the sliding face, and the current value of the volume change of the mixture is automatically recorded every five minutes for a specified time. The filled test molds were placed in a room with a constant relative humidity of 50% and a constant ambient temperature of 20 °C throughout the measurement. The device is shown in The same test procedures showed the difference in determining the properties of hardened concrete even after 90 days for mixtures with different mineral additives. Samples for these tests were stored in an aqueous medium at a constant temperature of 20 ± 2 °C throughout the maturation period. From each test mixture, three test specimens were made for each test, and the result is their average value.The watertightness of concrete to grade HV8 was determined according to the regulation of the Waterways Directorate of the Czech Republic . This te3 of concrete. This increase was necessary for the mixture containing (excluding the mined fine aggregate) crushed fine aggregate, and it can be expected that this increased dose was necessary due to the wetting of the surface of all aggregate grains. These results are in accordance with the general determinations regarding the specific surface of the aggregate described above. Also, in the following evaluation of the volume changes of the concrete composites, the connections between the parameters of the aggregate, such as grain shape, and the absorptivity and achieved volume changes will be further sought.All produced concrete mixtures reached the degree of consistency S4 through the slump cone test, more specifically, a slump of about 190 mm. To achieve the same degree of consistency for all produced concretes, it was necessary to make small corrections to the water–cement ratio and the dose of the superplasticizer, as can be seen in the The 3. The results show a significant difference between the compressive strength of concrete made from psammitic fluvial rock of the mined type and the remaining aggregates used. Based on these results, it can be concluded that it was the lowest quality aggregate of all the aggregates used in terms of its mechanical properties. On the contrary, no significant difference in the compressive strength of concrete was observed when using high-quality quartz-type mined aggregate compared to high-quality crushed aggregates used in this experiment. The results further showed a slight increase in the mechanical parameters of all produced concretes using a discontinuous grading curve and a larger maximum aggregate grain size, namely Dmax 22 mm. From a practical point of view, the formation of a discontinuous grading curve omitting the 4–8 mm fraction appears to be economically advantageous and, according to the results, is suitable for the production of concretes of higher strength classes.According to the achieved results of the compressive strength of concrete, it can be said that the required strength class was achieved for all the formulas. However, the achieved results showed in Furthermore, a significant difference in the flexural strength of concrete was observed between formulas made with mined aggregates and formulas made with crushed aggregates. It is obvious that the assumed larger specific surface of coarse aggregates, according to the achieved results, may seem more suitable for achieving higher values of flexural properties. These results correlate with the conclusion about a better incorporation of crushed aggregate into the matrix of cement stone, which can have a positive effect on the flexural strength of concrete. However, these obtained results probably also correspond to the mechanical parameters of the aggregates used, whereby metamorphic rocks of granodiorite type and igneous rocks of amphibolite type generally achieve significantly higher mechanical parameters than mined rocks. Therefore, it is not possible to unequivocally confirm or disprove these conclusions about increasing the bending parameters of concrete by better incorporating the grains of crushed aggregates into the cement matrix. The effect of the maximum aggregate grain size and the continuous or discontinuous aggregate grading curve was not clearly observed, although slightly higher values of flexural strength were achieved by concretes with a continuous grading curve and a maximum aggregate grain size of 22 mm.Significant differences between individual formulas, especially between mined and crushed aggregates, can be seen in the water tightness of concrete. Recipes with mined aggregates show lower resistance to the action of pressurized water, and this may directly relate to their higher absorptivity values. However, this trend was not directly confirmed by the water absorption test. The use of crushed fine aggregates in a suitable mixing ratio with natural fine aggregates seems to be highly suitable for practice based on all the achieved results. This technology of concrete production could bring a significant increase in the resistance of concrete, for example to the action of pressurized water, as evidenced by the obtained results.The main part of the performed experiment was to determine the impact of the type of aggregate on the volume changes of concrete. These results are shown in From the results of the volume changes of all produced concrete mixtures, it can be said that in all cases, more than 50% of the total volume changes will take place within 24 h of production see .In addition, a difference between the formulas with mined and crushed aggregates can be observed for all mixtures. Although the consistency of all mixtures was the same, the final shrinkage value is lower in mixtures with aggregates PM and PMQ, where there was also lower w/c. Based on the course of the volume changes, these results show that a major part of the volume changes is due to drying shrinkage, which corresponds to the results presented by many researchers.The following graphs in These dependencies are further analyzed using the statistical method of Pearson’s correlation coefficient. Pearson’s correlation coefficient is a statistical indicator of the strength of a linear dependence between two quantities. It takes values from −1.0 to 1.0, and the closer the value is to 1 or −1, the stronger the linear correlation between the tested quantities. Positive values then indicate a positive linear correlation and negative, vice versa. Reaching a value of 0 means that there is no linear correlation between the monitored variables ,52.The water absorption values of the aggregate mixture for the individual formulas were calculated from the weighted averages according to the given composition and the representation of the individual fractions. The same procedure was used for the shape of aggregate grains using the shape index value. Due to the impossibility of including small, crushed aggregate in the shape of grains, the dependence of the amount of all fine fractions up to 0.125 mm on the volume changes of concrete was determined. The binder component and all grains of the aggregate mixture with a size of less than 0.125 mm are included in these fine fractions.In order to more accurately determine the possible dependencies of the individual monitored parameters of the aggregate on the volume changes of concrete, the calculation of the Pearson’s correlation coefficient was performed. This coefficient was determined for a given parameter every 24 h and 7 and 28 days. The results are contained in The results of the statistical analysis of the results obtained using the Pearson’s coefficient demonstrates that for conventional ready-mixed concretes, the production of mixtures with a discontinuous grading curve is not unsuitable from the point of view of negatively influencing the undesired volume changes of the composite. A significant dependence was observed in the overall water absorption of the aggregate mixture on the volume changes of the composite. The results of the experiment clearly prove that although the mined aggregates used achieve higher values of water absorption, this parameter is linearly and indirectly dependent on the resulting volume changes of the composite. This fact directly relates to the linear dependence of the water dose for the production of the mixture and its resulting volume change. It is obvious that although the mined aggregates used have a higher water absorption value, lower doses of mixing water were used for the production of the mixtures with these aggregates, which had a positive effect on the resulting volume changes of concrete composites ,18,19. TFor practice, it is beneficial to prove the effect of the type of aggregate used on the volume changes of the composite from its production to the age of 28 days. It is obvious that the effect of aggregate is most noticeable especially in the first 24 h after the production of the mixture, when the most significant volume changes occur mainly due to drying.The concrete mixtures produced reached, as in the previous part of the experiment, a cone slump of about 190 mm. This degree of cone slump was again achieved thanks to a small correction of the water–cement ratio and the dose of the superplasticizer, as can be seen from the tables with the composition of individual formulas. For the mineral additives, the correction of the water–cement ratio and the dose of the superplasticizer were expected according to their grain morphology. From the analysis of the grain morphology of the mineral additives used under the scanning electron microscope, it is evident that the grains of the high-temperature fly ash are predominantly spherical in nature with a vitrified surface. For this mineral additive, a positive effect on the consistency of the concrete mixture was expected due to its addition. This fact has been proven in many research studies in which the effect of a sliding bearing is attributed to high-temperature fly ash, which have a ball shape . In the The required strength class C 45/55 has been achieved for all mixtures, and for the use of the active additives, their pozzolanic or latent hydraulic activity is then evident with an increasing time from production. Although the compressive strength results after 28 days show slight mutual differences, these differences do not exceed more than 13%. The results show that concretes made of quality mined aggregates, which, for this experiment, are of the quartz type, can achieve higher compressive strengths than the concretes with crushed aggregates with the same composition. Regarding the flexural strength of concrete, the results obtained are the opposite, and, in accordance with previously written conclusions, concretes with crushed aggregate achieve higher values.The results and courses of the volume changes of the concrete mixtures are contained in The results of the volume changes of the individual mixtures confirm the conclusion about the most significant part of the volume changes within 24 h of production in The results of the experiment indicate the suitability of using mineral additives to reduce volume changes. It has been proven that all the mineral additives used can be helpful in eliminating volume changes in concrete mixtures, where the most significant effect can be seen when using very finely ground limestone and high-temperature fly ash. For very finely ground limestone, this fact can be attributed to its practically inert nature, and for high-temperature fly ash, its grain morphology, which has a positive effect on the possible reduction of the water–cement ratio .It also seems constructive to point out the difference in the values of the volume changes for the mixtures with mined and crushed aggregates determined by both methods. Although most of the worldwide published results describe the suitability of using crushed aggregates for volume changes of the mixture, the opposite is true when determining volume changes immediately from the production of the mixture. Based on the graphical course of the volume changes in the first hours of maturation, this fact should probably be attributed to the different loss of moisture from the mixture, when a larger dose of water to moisten the grains of the crushed aggregate causes a larger value of volume changes. This trend can be seen in The following graphs in The results of the calculation of the Pearson’s correlation coefficient are contained in Using Pearson’s correlation coefficient, it was not possible to prove a direct dependence of the amount of binder component, which is formed by Portland cement and different doses of diverse additives, on the volume changes of the composite see . This faThese results further directly relate to the dose of water required to achieve the same degree of consistency of all mixtures and the resulting volume changes. It is obvious that in this part of the study, a dependence was found between the dose of mixing water and the volume changes of the composite. This fact directly relates to the water–cement ratio, which, however, is significantly influenced by the grain morphology of the individual types of additives. The most suitable grain shape from the point of view of morphology from the images of the grains of the individual additives used  shows hiIn addition to the effect of the individual types of additives used on the rheology of composites, their impact on the resulting volume changes of concrete is further attributed to their chemical effect. Very finely ground limestone behaves almost inertly from the point of view of chemical processes, and its use as a filler makes it possible, above all, to form a denser matrix of the composite. This can have a partial effect on the outflow of water from the composite after its production, which can have a direct effect on drying shrinkage. The course of the volume changes of the mixtures with very finely ground limestone correspond to this statement and is evident, especially with a longer maturation period. Although, for example, for the mixtures with ground blast furnace slag, shrinkage is almost complete after 28 days. For mixtures with very finely ground limestone, a more pronounced direction of the shrinkage curve can be seen even after this age. This difference between the volume changes after 28 and 60 days can still be about 15% for the mixtures with very finely ground limestone. For these mixtures, it is necessary to pay increased attention to the volume changes with a longer maturation period.Of all the types of additives used, the use of high-temperature fly ash seems to be the most suitable for practicing eliminating negative volume changes. In addition, this additive has an incredibly positive effect on the development of hydration temperatures, which is widely used in the concreting of massive structures. In concrete mixtures, where the use of high-temperature fly ash is unsuitable, it is possible to eliminate volume changes using very finely ground limestone or ground blast furnace slag.Thanks to an extensive study, the effect of the individual basic components of a concrete composite on its volume changes was clarified. The effect of the type of aggregate , the characteristics of aggregate  and the aggregate grading curve (continuous and discontinuous curve) were analyzed. Furthermore, the effect of mineral additives  was examined. The basic mechanical and physical parameters were determined for all the produced concrete formulas. The obtained results will allow the design of concrete composition with low-volume changes and the reduction of shrinkage cracks, which will significantly contribute to the higher durability and resistance of concrete to erosive effects and ingress of corrosion agents.max 16 mm and continuous grading curve and Dmax 22 mm and continuous grading curve with omission of fraction 4–8 mm—have no significant effect on volume changes of the composite. ○max 22 mm show slightly higher strength parameters.Mixtures with a discontinuous grading curve and a DMaximum aggregate grain and type of grading curve—more specifically, D○Mined aggregates have a more suitable grain shape, and for the production of concrete mixtures, it is possible to use lower doses of mixing water to achieve the same degree of consistency.○A higher water absorption of mined aggregates does not have a negative effect on volume changes of the composite.○A higher specific surface area of crushed aggregate grains has a negative impact on the necessary dose of mixing water and subsequent shrinkage by drying.○The most significant effect of the type of aggregate on the volume changes of the composite is the first 24 h.Mined aggregates are more suitable for the production of concrete mixtures with low volume changes.From the point of view of the assessment of physico-mechanical properties such as compressive strength or water absorption, comparable results were obtained. The compressive strength of mined quartz-type aggregate is comparable to the compressive strength of high-quality crushed aggregate.○The addition of high-temperature fly ash proved to be the most suitable. This fact is attributed to the reduction of the development of hydration heat by the use of high-temperature fly ash and the spherical shape of the fly ash grains, thanks to which the amount of mixing water can be eliminated.○Regarding concretes with the addition of very finely ground limestone, a more significant course of volume changes was recorded, even after 28 days from the production of concrete.In the case of the use of mineral admixtures with mined aggregate, it is clear that all used additives had a positive effect on the resulting shrinkage value of the concrete compared to the reference mixture.Compared to the reference mix design with crushed aggregate, the effect of shrinkage by mineral additives is not so clear. This phenomenon is caused by the higher specific surface area of, for example, finely ground limestone, where this admixture in combination with crushed aggregate requires the use of a slightly larger amount of mixing water and plasticizer.The following findings can be summarized from the results of the performed experiment:


The results obtained indicate the possibility of a wider use of ground limestone (LL) in cement composition. This is important in the case of limited market availability of fly ash and granulated blast furnace slag. The tests conducted on concrete have shown that the necessary condition for obtaining a high strength class and durability of concrete from CEM II/C-M and CEM VI ternary cements is low water–cement ratio. Durability characteristics of concrete  made of CEM II/C-M and CEM VI cements were determined after 90 days of hardening. This period of curing reflects the performance properties of the concrete in a more effective way. The paper presents the composition and properties of low-emission ternary cements: Portland multicomponent cement CEM II/C-M and multicomponent cement CEM VI. In the ternary cements, Portland clinker was replaced at the levels of 40% and 55% with a mixture of the main components such as limestone (LL), granulated blast furnace slag (S) and siliceous fly ash (V). Portland multicomponent cements CEM II/C-M and CEM VI are low-emission binders with CO It is suggested that the emission levels reach around 350–410 kg per Mg of cement [In 2017, the global production of cement, the base component of concrete, amounted to almost 4.65 billion Mg [el (40%) . It is cproduction of multicomponent cements CEM II-CEMV according to EN 197-1  using simodification of the production process of cement clinker by modification of the raw material set  and use of alternative (non-fossil) biomass-rich fuels.The possibilities of emission reduction include two solutions in the cement production process ,7:producIn the case of production of CEM II-CEM V multicomponent cements, the main components are usually by-products of industrial processes such as siliceous fly ash (V), calcareous fly ash from coal dust combustion in the power industry or granulated blast furnace slag from iron metallurgy (S) ,9,10. Th3A to form carboaluminates means that CaCO3 may play, to a limited extent, the role of a regulator of setting time. This results in the reduction of the amount of gypsum, which is necessary to regulate the setting time [Calcium carbonate, the main component of limestone, reacts with calcium aluminates to form hydrated calcium carboaluminates. The presence of hydrated calcium carboaluminates inhibits the transition of ettringite to monosulfate, thus, in hydration products the amount of monosulfate decreases or disappears while the amount of ettringite increases . The facing time .3S phase reaction. This effect is explained by the nucleation effect, in which CaCO3 grains act as additional crystallization germs for cement hydration products [In addition to the reaction with calcium aluminate, the addition of limestone to the cement may accelerate the Cproducts ,20,21. Lproducts ,23,24. Bproducts , which e2 emissions originating in the composition of CEM II/C-M and CEM VI cement was also calculated, as well as the level of CO2 emissions from the production of concrete with the use of tested cements.This paper presents the results of research on Portland multicomponent cement CEM II/C-M with 40% of non-clinker main components and multicomponent cement CEM VI with 55% of these components. Ground granulated blast furnace slag (S), siliceous fly ash (V) and ground limestone (LL) were used as non-clinker main components. Concrete tests were performed for the analyzed cements CEM II/C-M and CEM VI. The basic properties of concrete mixture and hardened concrete were determined with a view to future use of cements in construction practice. The level of COThree types of non-clinker ingredient were used in the study: granulated blast furnace slag from iron metallurgy, siliceous fly ash from the combustion of coal in power plants, and natural limestone.The chemical composition of the cement components and selected physical properties are given in 3 content (5.0%) in order to obtain a normal SO3 content (max. 3.5%) when mixed with the other main components of the cement. Therefore, this cement is a semi-finished product in the process of manufacturing multicomponent cements. The clinker content in the cement was 90%.In the slag phase composition (S), the dominant component is the vitreous phase, the quantitative content of which  is 98%. In fly ash, next to the vitreous phase, the main crystalline components identified are quartz, mullite, hematite and magnetite. The Portland cement CEM I is a semi-finished product with an increased SO2/g , fly ash cement C(40V) and limestone cement C(40LL) were also tested .The properties of cements were determined according to the procedures of EN 196 and the density according to the standard on the properties of aggregates EN 1097-7 .Based on Portland multicomponent cements CEM II/C-M and multicomponent cements CEM VI, concrete mixes with the following composition, given in 3 of concrete mix at a ratio w/c = 0.60 and type II, containing 340 kg of cement in 1 m3 of concrete mix at a ratio w/c = 0.35. Natural gravel aggregate with a fraction up to 16 mm and sand 0–2 mm as fine aggregate were used in the concrete mixture. A superplasticizer (PCE) based on polycarboxylate ether was used in the composition of concrete with reduced water–cement ratio (w/c = 0.35).Two types of concrete were prepared—type I containing 300 kg of cement in 1 mThe properties of concrete mixtures and hardened concrete were tested according to the methodology included in the standards, which are presented in 2/g. Cement slurries with ternary cements did not show volume changes due to swelling 2 from cement hydration increases). The final strength (after 360 days) of multicomponent cement C(30S-10LL) is similar to that of comparative cement C(55S), while in the case of cement C(35S-20V) there is a slight decrease in the final strength, compared to cement C(55S)  . This deThe partial replacement of fly ash by limestone C(30V-10LL) in cement composition, allows a cement to be made with higher early strength (after 2 days) and higher final strength than the reference cements C(40V) and C(40LL). The higher early strength in the presence of limestone may result from the caulking effect as well as the small amount of carboaluminates formed. On the basis of the results obtained, it can also be observed that the addition of LL limestone decreases the strength of cement mortars to a greater extent in combination with siliceous fly ash (C(30V-10LL)), while the use of limestone (even up to 20%) in combination with ground granulated blast furnace slag (cements: C(30S-10LL), C(35S-20LL)) gives a much smaller decrease, slightly less than in the case of using the S slag composition with fly ash V-cement C(35S-20V).The properties of concrete mixture are presented in 3. The air content was low and ranged from 0.6% to 1.0%. Decreasing the water-cement ratio to the level w/c = 0.35 resulted in an increase in the density of concrete mixtures by about 70–80 kg/m3 and an increase in air content to 1.6–2%. The increase in aeration of the concrete mixture is typical of using liquefying admixture.The density of all concrete mixtures with the ratio w/c = 0.60 was similar and ranged from 2350 to 2360 kg/mCompressive strengthThe compressive strength was determined, after 2, 7, 28 and 90 days of curing, on 10 cm cubic samples. For concretes with w/c = 0.35, strength tests were also performed after 1 day of curing. The results are presented in The highest compressive strength, at w/c = 0.35 and 0.60, was obtained by concrete made of Portland multicomponent cement C(30S-10LL). The lowest compressive strength was achieved with C(30V-10LL) on Portland ash and lime cement, despite the fact that it contained more Portland clinker compared to the other two CEM VI cement concretes. Limestone and siliceous fly ash show a synergistic effect only with early strength (2 days) and only with 10% addition of limestone, which confirms the results obtained by De Werdt et al. ,41,42. Tth day. It can be noted that the lowest results were obtained for concrete using cement C(30V-10LL), however, the compressive strength after 28 days was nearly 70 Mpa and was almost twice as high as the strength obtained at w/c = 0.60. To sum up, it should be stated that a low w/c ratio is a very effective factor in shaping the strength characteristics of concrete made of cements with low Portland clinker content (Decreasing the water-cement ratio (w/c) from 0.60 to 0.35 resulted in a significant increase in the compressive strength of concretes made of all cements tested . This in content .Water absorption and water penetration under pressureAll tested concretes, at the same w/c, show similar water absorption. For concretes with w/c = 0.60 the absorption varies between 6.6% to 7.0%, while for concretes with reduced w/c = 0.35 it is much lower and ranges from 3.3% to 4.1% . ExtensiThe results of the study on the depth of water penetration under pressure  show tha2 from the hydration of silicate phases of Portland clinker). The impact of this reaction on the properties of mortar (concrete) is earliest visible about 28 days and later nd later b. The adCarbonation susceptibility2 concentration 4%, the test duration was 70 days (accelerated method). Analyzing the results obtained for concretes at w/c = 0.60, it can be seen that the highest depth of carbonation is characterized by concrete with Portland multicomponent cement C(30V-10LL), after 28 days of hardening the depth of carbonation reaches 29.7 mm, and after 90 days it is 18.6 mm. Reducing the water–cement ratio to the level w/c = 0.35 very effectively lowered the depth of concrete carbonation ) for concretes with coefficient w/c = 0.35. The test was performed after 28 and 90 days of concrete curing. The result of the test is positive if the decrease of compressive strength is less than 20% and the loss of mass is not more than 5% of weight. The test of concrete surface resistance to frost (56 cycles) in the presence of NaCl de-icing salt was also performed. Concrete was evaluated after 28 days of curing. The test results are presented in The type of applied cement affects the durability of concrete under cyclic freezing and unfreezing conditions, especially when de-icing agents are used. The worst results were obtained for concrete made of Portland multicomponent cement C(30V-10LL) ; Table 8When analyzing the results of the surface resistance of concrete to frost in the presence of de-icing salt , it is c2 emissions from 1 Mg of cement , the strength levels are much higher and the difference in the level of the obtained compressive strength depending on the composition of the cement starts to fade. The CO2 emission level per 1 MPa is significantly reduced also, e.g., in the case of CEM II/C-M (30V-10LL) cement from 4.9 kg (w/c = 0.60) to 2.3 kg (w/c = 0.35). Considering the compressive strength after 90 days, CO2 emissions are lower, on average by about 0.7 kg at w/c = 0.60 and about 0.2 kg at w/c = 0.35. This is due to the fact that cements with a high content of the main components other than Portland clinker (mainly granulated blast furnace slag and/or fly ash) have a significant strength increment between 28 and 90 days of hardening.The concrete emission level was calculated based on the level of COf cement . The resvery low . When co2 emissions) confirmed the advisability of further development of the assortment of general-use cements with the following ternary cements: Portland multicomponent cement CEM II/C-M and multicomponent cement CEM VI. The properties of these cements and the concretes made with them are the result of the properties of the main components and the synergistic interaction of the composition: granulated blast furnace slag S-limestone LL, siliceous fly ash V-limestone LL, granulated blast furnace slag S-siliceous fly ash V.The results of the research as well as ecological aspects  with limestone (LL) than fly ash (V) with limestone (LL). This is due to the higher activity of the ground slag compared to fly ash (V). The results obtained also confirm a very good synergy effect, known from construction literature and practice, between slag (S) and fly ash (V). A characteristic feature of CEM II/C-M and CEM VI ternary cements is a low level of early compressive strength (up to 7 days) and a significant increase in compressive strength at later stages .A typical attribute of CEM II/C-M and CEM VI ternary cements is the low level of early compressive strength (up to 7 days) and a significant increase in compressive strength at a later date .The results obtained indicate the possibility of wider use of ground limestone LL in cement (concrete) composition. This is important in terms of the limited market availability of fly ash and granulated blast furnace slag.The results obtained from tests on concrete showed that a low w/c ratio is a prerequisite for obtaining high strength class and durability of concrete made of CEM II/C-M and CEM VI ternary cements. This can be achieved by using the latest generation of liquefying admixtures (superplasticizers).The durability characteristics of concrete  from CEM II/C-M and CEM VI cements should be determined after 90 days of hardening. This period of curing better reflects the performance properties of the concrete.2 emissions ranging from 340 (CEM VI) kg to 453 (CEM II/C-M) kg per Mg of cement. Because of a high content of non-clinker main components, these cements characterize a much lower degree of hydration after 28 days of hardening than ordinary Portland cement CEM I. The presence of slag (S) and fly ash (V) results in a significant increase in the strength of low-emission cements between 28 and 90 days of hardening, and hence a better effect in terms of reducing emissions per 1 MPa is achieved. In some countries, Poland among others, for this reason the quality of concrete with low-emission cements is assessed after 90 days.Portland multicomponent cements CEM II/C-M and CEM VI are low-emission binders with COBased on the results of the research carried out, the following conclusions were drawn:


The study of new and innovative quasi-brittle materials offers new possibilities for use in construction, but detailed knowledge of their behavior and mechanical properties is required. The use of new materials in the design solution of a structure is usually associated with numerical methods, which has a number of both advantages and disadvantages. Sophisticated numerical methods, without a sufficiently detailed input knowledge, can provide highly variable results with little informative value. The main goal of this article is to present the procedure for the identification of fracture mechanical parameters for a specific concrete with the use of developed inverse analysis combining multi-criteria decision analysis, stochastic modelling and nonlinear analysis. Subsequently, the identified mechanical parameters of concrete are used for the parametric study of shear resistance of structural beams without shear reinforcement, as an alternative or generalized approach to the study of damage to concrete and concrete structures. This research includes an experimental program using 24 reinforced concrete beams and a detailed determination of basic and specific mechanical properties during laboratory tests. The process of inverse analysis is illustrated in detail for the solved task. The use of nonlinear analysis for detailed failure modelling is based on a 3D computational model and a fracture plastic material model for concrete. Finally, the results of the experimental program and numerical modelling are discussed, leading to a number of conclusions. Concrete is among the most important materials  used in The fracture mechanics  are fit Since the direct determination of some parameters, for example, fracture energy or tension soften function , is expeThe design approach of inverse analysis includes the utilization of a series of methods, in particular the use of a multi-criteria analysis  for the Model Code 2010 [The use of new materials in designs is usually associated with numerical methods , which hode 2010 . On thisode 2010  or fractode 2010 ,23 for node 2010 ,25.The use of nonlinear analysis and material models is also connected with other numerical methods, namely, the finite elements method , the metThe main design criteria include the check for bending moment , shear failure ,27 or puTypical structures include not only reinforced concrete beams without shear reinforcement, but other more complicated cases ,33 such The experimental program and numerical modelling will focus on reinforced concrete beams without shear reinforcement. This research includes an experimental program with 24 RC beams with specialized concrete, where existing analytical approaches are not sufficiently applicable. The experimental program also includes a detailed determination of basic and specific mechanical properties through laboratory testing. The process of inverse analysis is illustrated for the solved task. The use of nonlinear analysis for detailed failure modelling is based on a 3D computational model and a fracture plastic material model for concrete.Requirements for the generalized specification of the behavior of quasi-brittle materials, such as concrete, in fracture mechanics are expressed by basic material parameters including compressive strength, modulus of elasticity, tensile strength, and by specification of softening and the energy required to fracture. In particular, in the case of the latter property, this value has a significant impact on the total fidelity of subsequent nonlinear analyses of building structures.Since the direct determination of the specific energy to fracture for crack propagation is experimentally very demanding, there is an option to use sophisticated methods within the inverse analysis and use results from laboratory testing in combination with numerical modelling to identify unknown parameters . The preThe inverse analysis procedure is shown in Key phases of the inversion analysis are stochastic modelling and the generation of input parameters for the identification of material characteristics. Specifically, the Latin hypercube sampling (LHS)  method aInput data from stochastic modelling  were proFrom the individual stiffness of finite elements For tensile softening in concrete, the form of Crack Opening Law  was usedw is the crack opening, wc is the crack opening at the complete release of stress, σ is the normal stress in the crack, Gf is the fracture energy and ftef is the effective tensile strength. This was subsequently based on the experiments modified as follows:X is the possible set of variants and x are individual members of variables with the size vector n.The multi-criteria analysis ,35 used iP criteria of each variant based on the information available. In addition, the multiplier of individual calculation variants was determined asThe calculation was based on the calculation of multipliers of iw. The calculation continued with data normalization into dimensionless values. After setting up all members of the criteria matrix, the total multiplier of variants was calculated, from which the most suitable variant was selected as an identification result. A detailed description of the theory and application of the multi-criteria analysis is shown in [The calculation must also include weights of individual criteria shown in ,35.The generated input data, obtained load-displacement (LD) diagrams of the numerical model and experiments were compared and processed using multi-criteria analysis in MATLAB. When there was no sufficient result , the whole process was repeated, assuming that up-to-date results were used and taken into account in the next input data generation. The evaluation of the identified values was carried out further on a multilevel comparison.Other approaches to identify mechanical parameters included within inverse analysis are neural networks and stochastic modelling .The basic concept of the experimental program and numerical modelling are shown in The specific problem of shear failure is selected for the numerical analysis of structural beams. For a closer understanding of the shear failure of reinforced concrete beams without transverse reinforcement, basic approaches based on design code or current research directions are presented. A typical failure of a reinforced concrete beam is shown in The complexity of the problem of shear failure can be illustrated by comparing the total load capacity for the investigated type of beams in b is the width of the cross-section, d’ is the depth of beam and τ is shear stress. The shear failure mechanism is shown in Theoretical shear resistance and failure of beams can be formulated  by(8)VREurocode 2 [Cc is the empirical coefficient of 0.18; k is the parameter that takes the size effect into account; fc is the concrete´s compressive strength; bw is the width of the cross-section; d is the effective depth of the cross-section; and The current approach in rocode 2  sets the article .VR refers to the shear resistance, b to the width of the member, d to its depth, fc to concrete´s compressive strength, dg to the aggregate size and w is the reference value of the critical shear crack opening. The ultimate shear force of beams and one-way slabs [fct is uniaxial concrete tensile strength, b is the width of the member, d is its depth, vc is the parameter of compression chord and vw is the parameter of cracked concrete web. The effect of cracked concrete web [fct is uniaxial concrete tensile strength, d is its depth, Ec is the modulus of elasticity of concrete and Gf is concrete fracture energy.New approaches in the solved area include the Critical Shear Crack Theory (CSCT)  from Proay slabs  without rete web  can be wModel Code 2010 [fc is compressive strength. The formulation does not directly affect, for example, aggregate size or tensile strength. Other known relationships to VOS 1983 [fct is the uniaxial concrete tensile strength. From the new recommendation [fcm is the mean value of the concrete compressive strength and dmax is the maximum aggregate size.Among the known recommendations for the calculation of fracture energy for concrete is the ode 2010 :(14)Gf=7VOS 1983  includeendation , we can The issue of shear failure is also relevant for reinforced concrete beams with shear reinforcement. In summary, the research of shear failure is often based on simplified test schemes that are not suitable for complex reinforcement concrete structures or specific concretes. These research approaches differ in the resulting constructive formulations, but also in the input parameters, the interpretation of the failure mechanisms and the control shear transmissions. There is no general consensus on solving a research task where the resulting load-bearing capacity is often very different.There are a number of other theoretical approaches that vary by conciseness and amount of information required. However, it is clear from the above that it is appropriate to apply a generalized solution in the area of shear failure, which can be represented by advanced numerical modelling with 3D computational models ,24. Numefc is the compressive strength, and k, n, α, and β are non-dimensional coefficients, which can be found in The experimental program included a comprehensive set of basic and specialized laboratory tests, followed by a comprehensive series of reinforced concrete beams without transverse reinforcement with differing degrees of reinforcement. The specific fine-grained, Baumit ProofBeton ©, with a fine aggregate up to 4 mm was found to have the following characteristics: It was waterproof, frost-resistant and with salt, and suitable for contact with drinking water . The bask, within the interval 0.2–0.4, and the coefficient n, within the interval 0.6–0.8, are usually used for the split tensile strength. In the case of the modulus of elasticity, the difference in these coefficients is greater. The relationship of the modulus of elasticity as a function of the compressive strength is often limited and distorts the results. The quality of the aggregates and the water–cement ratio also play a role.To use the relations in The main test program involved 24 reinforced concrete beams without transverse reinforcement. Four series are chosen for testing that differ in their degree of reinforcement, where each series had six beams. Specifically, the reinforced concrete beam was tested in a three-point bending test. The beam had a rectangular cross-section of 100 × 190 mm and a typical span of 900 mm. The diagram of the three-point bending test is shown in For the sake of clarity, the overall summary of basic, bending and structural tests ,62,63,64Summary results from the basic tests ,62,63,64Fracture energy is an important mechanical parameter but its laboratory determination is difficult and there are more test methods that give different results. However, on the basis of laboratory tests, a comparison was made from the recommendations in Three control tests were performed to verify the aptness of the tensile strength calculation in the three-point bending test with a 25-mm notch; the results are shown in A total of twelve tests were performed in the three bending tests of small reinforced concrete beams with reinforcement, with three beams used for each test series. The resulting bearing capacity is evaluated graphically in As an example, in Results from the small reinforced concrete beams were used in the inverse analysis to determine fracture energy. For the fine-grained concrete mix used, the fracture energy relations (14–16) are unsuitable. The procedure for inverse analysis described in A comparison of the experiment with numerical calculations adopting a different fracture energy for the selected small beam with the reinforcement diameter 12 is given in The main part of the research and experimental program was focused on the structural elements of reinforced concrete beams without transverse reinforcement. However, unlike typical analytical models in the recommendations and design codes, the shear crack theory analysis and stage was solved by advanced 3D numerical modelling that respects the propagation of cracks in concrete. The experimental program included four series of beams, where the reinforcement cross-section was from 0.3% to 1.2%.The reinforced concrete beams were reinforced with 6, 8, 10 and 12 mm diameter reinforcements. The specifics of the research program are that each series included 6 beams. The range was chosen because the tensile strength of the concrete is also important for the failure mode., i.e., a greater dispersion of the shear failure results can be expected. In general, the tensile strength has a wider range of values, as verified in Mmax in the cross section and the relative deformation calculated to the maximum deformation of wmax 1/200 of the span of the beams. The range of coefficients of variation was between 3% and 6% for the individually reinforced type concrete beams and the average value was 5%. Following this, 3D numerical modelling of experiments was carried out using the identified mechanical properties of concrete. Numerical simulations, calculation parameters, and the calculation model differed only by the reinforcement used. The individual computational models are shown in Larger cracks were found in beams with smaller reinforcement diameters. A summary of the results is provided in Based on the experimental program, it was found that the average compressive strength of 48.85 MPa on cylinders was in the usual ratio to the compressive strength of 56.47 MPa on cubes: The obtained ratio of 0.865 is very close to the usual ratio of 0.85. The influence of fine-grained concrete aggregates had no significant influence on the shape of the test body used. The determined split tensile strength and its recalculated uniaxial concrete tensile strength were less than most recommendations. A reduction coefficient of 0.9 was used for the conversion of strengths. Considering the cube compressive strengths and the split tensile strength, it can be concluded that the coefficient of variation was significantly higher for the split tensile strength. In both cases, however, the test set values were in the interval quantile 0.01–0.99. The fracture energy parameter is also related to uniaxial tensile strength. Comparing the recommendations for the calculation of fracture energy and the results of the inverse analysis, it is clear that the use of formulas for typical concrete is usually not appropriate: The difference in the resulting beam load capacity and the experiment can be up to about 47%. The use of inverse analysis to identify the fracture energy parameter has proved to be a more suitable approach.Ensure there is a sufficient set of basic mechanical properties .Appropriately select specialized tests for direct or indirect determination of specific parameters  or use recommendations. Small reinforced concrete beams were used to solve this specific problem. The sensitivity of the fracture mechanical parameters themselves is broadly discussed in .If inverse analysis is used, select appropriate methods so that results are sufficiently reliable. Among the possible methods belongs the presented method of combining multi-criteria decision analysis (MCDA) , stochasThe use of numerical modeling and nonlinear analysis requires the appropriate selection of the material model and adherence to the recommendations for nonlinear solutions. Calculation parameters include type of finite element, finite element mesh, a mathematical solver, and conversion criteria. The modelling in this study was based on the recommendations in .The analysis process itself should take into account and meet the following criteria:The resulting fracture energy identified was 44.3 N/m. Numerical modelling and shear failure analysis were performed based on a comprehensive set of mechanical properties of the concrete used. 3D numerical modelling made it possible to respect the propagation of cracks in concrete.x is the degree of cross-section reinforcement. In both cases, the confidence level is greater than 92%. The predicted shear capacities and failure of numerical 3D models can be considered very good.The results of tests and numerical modelling can be interpreted in the form of shear capacity of the beam in This research presents an approach to the determination of fracture mechanical parameters for specialized fine-grained concrete for which it is not possible to use the available recommendations. The presented inverse method combines multi-criteria decision analysis (MCDA), stochastic modelling with Latin hypercube sampling (LHS) and nonlinear analysis.Laboratory tests of compressive strength and split tensile strength for the specialized concrete show that the coefficient of variation is nearly two-times greater for the transverse tensile strength.The split tensile strength for the fine-grained concrete mixture was significantly lower than foreseen in the recommendations.A well-known coefficient of 0.85 works well to convert between compressive strengths for cubes and cylinders.The modulus of elasticity is significantly smaller than indicated in most recommendations and research.In the case of fracture energy determination, inverse analysis can be used to identify it, but this requires the use of a specialized test program and numerical methods. Recommendations for the calculation of fracture energy can by only usually intended for typical concretes;The chosen approach to shear failure modelling allows for the load capacity and failure mechanism to be correctly understood. Complex mechanical properties of concrete and numerical modelling can then be used for more complex structures that cannot be represented by analytical models.Part of the research and experimental program was focused on the determination of load capacity of reinforced concrete beams without transverse reinforcement and modelling of shear failure. However, knowledge of detailed mechanical parameters of concrete is necessary to gain an understanding of the problem; especially in the case of specific and high-performance concretes, the mechanism of damage and behavior may differ compared with typical concretes. This case was solved by this research, which was a specialized fine-grained concrete with aggregates up to 4 mm. Numerical modelling with a 3D computational model and fracture-plastic material model was used for determination of shear resistance of the beam. This approach made it possible to effectively describe the overall load-bearing capacity as well as the mechanism of failure and collapse of the beam itself. The following conclusions can be drawn:Another benefit of the approach presented for the analysis and modelling of concrete structures is that it enables the task to be further extended by the problems of durability and reliability of structures. In further research, the author will focus on the optimization of the method for the identification of mechanic parameters and the possibility of using fiber-reinforced concrete for beams without shear reinforcement, as this research is related to the solved problem.


Mechanically, it is demonstrated that PIK3CD-AS2 bound to and maintained the stability of Y-box binding protein 1 (YBX1), a potent destabilizer of p53, by impeding its ubiquitination and degradation. Downexpression of YBX1 reversed PIK3CD-AS2-mediated inhibition of p53 signaling. Additionally, the therapeutic effect evaluation of a locked nuclear acid (LNA) specifically targeting PIK3CD-AS2 showed an anti-tumor activity in mice with A549 cells xenograft and p53 wild-type LUAD patient-derived tumor xenograft (PDTX) model. Clinically, the high expression of PIK3CD-AS2 showed a poor disease-free survival in p53 wild-type patients in TCGA database. Our findings suggest that PIK3CD-AS2 regulates LUAD progression and elucidate a new PIK3CD-AS2/YBX1/p53 signaling axis, providing a potential lncRNA-directed therapeutic strategy especially in p53 wild-type LUAD patients.The underlying mechanisms of long non-coding RNAs (lncRNA) participating in the progression of lung cancers are largely unknown. We found a novel lncRNA, PIK3CD antisense RNA 2 (PIK3CD-AS2), that contributes to lung adenocarcinoma (LUAD) progression. The expression characteristics of PIK3CD-AS2 in LUAD were analyzed using microarray expression profile, The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, and validated in 92 paired LUAD tissues by chromogenic in situ hybridization. Our data confirmed that PIK3CD-AS2 expression is a crucial regulator of LUAD progression and associated with shorter patient survival. In vitro studies showed that PIK3CD-AS2 increased cell growth and slowed apoptosis in p53 Among NSCLC, lung adenocarcinoma (LUAD) is the most common histopathologic type. Patients with early stage of LUAD usually have better outcomes but only 23% of lung cancer cases were found at an early stage. Once the cancer has spread, it is often shown a limited survival.Lung cancer, predominantly non-small cell lung cancer (NSCLC) is the deadliest malignancy worldwide, accounting for the largest number of cancer-related mortality3. Anaplastic lymphoma kinase (ALK) rearrangement are found in 7–9% of LUAD cases, and crizotinib has been demonstrated to increase patient median progression-free survival to 8–10 months4. During types of NSCLC driver mutations, genetic abnormalities in the tumor protein 53 (TP53) gene are the most frequent alterations, attracting plenty of therapeutic studies6. Two p53 reactivating compounds, APR-246 and COTI-2, have been found to display anticancer activity in phase I clinical trials7. Given the wild-type form of p53 is dominant over the mutant, novel treatments aiming to sustain wild-type p53 activity become an alternative opportunity. Growing evidences suggest that restoring wild-type p53 function by gene-replacement strategies could suppress lung cancer progression10, indicating a potential clinical applicability, although these p53 restoration approaches still remain preliminary.Targeted therapy based on driver genes opened a new era of cancer treatment in the past decades. Data from omics profiling studies have identified lots of driver gene mutations. It is well-known that the presence of epidermal growth factor receptor (EGFR)-activating mutation makes at least 20% of LUAD patients eligible to tyrosine kinase inhibitor (TKI) therapy11. In NSCLC, it is demonstrated that estrogen receptor β can promote cancer vasculogenic mimicry formation and cell invasion via altering long non-coding RNA (lncRNA) MALAT1/miR145–5p/NEDD9 signaling12. Environmental carcinogen nickel exposure led to lncRNA MEG3 downregulation, further initiated PHLLPP1 transcriptional decrease and hypoxia-inducible factor-1α protein translational increase, eventually inducing tumor malignant progression13. Our group focuses on ncRNAs in NSCLC and previously identified a novel lncRNA LUADT1 promoting cell cycle and tumor growth via epigenetically blocking p27 expression14. We also demonstrated high expressed SBF2-AS1 functioning as a competitive endogenous RNA facilitates the progression of lung cancer15. In addition, we first found that a proto-oncogenic circular RNA (circPRKCI) coming from one of the most frequent genomic amplificated regions 3q26.2, that is significantly overexpressed in LUAD tissues and promotes tumorigenesis16.Non-coding RNAs (ncRNAs) are new emerging targets for tumor therapy. They have been identified to function in cancer as oncogenic drivers and tumor suppressors, or as key regulators which form an orchestrated interaction modulating well-known genes14, as a candidate oncogene contributed to cancer growth via suppressing p53 signaling. Lack of PIK3CD-AS2 restored p53 expression levels and offered a possibility of anti-tumor activity. Our study provides the first evidence of the biological function of lncRNA PIK3CD-AS2 and its underlying role in YBX1/p53 axis, which could be used as a potential therapeutic target for lung cancer clinical practice.Here, we investigated another LUAD-upregulated lncRNA PIK3CD antisense RNA 2 (PIK3CD-AS2), previously reported in our lncRNA microarray GSE66654P < 0.001, Fig. P < 0.001, Fig. P < 0.05, Fig. P < 0.001; Fig. By analyzing mRNA and lncRNA expression profiles from our previous LUAD microarray data (GSE66654), we found that PIK3CD-AS2 had more than 13-fold changes in tumor tissues vs. paired non-tumor tissues Fig. . It was P = 0.03) and histological differentiation (P = 0.04). Kaplan–Meier analysis and log-rank test showed a remarkable correlation between tumor-associated PIK3CD-AS2 expression and worse overall survival outcome  by chromogenic in situ hybridization (CISH), and observed a similar expression tendency Fig. . As showPIK3CD-AS2 has three transcripts, in which ENSG00000231789 is the longest one with three exons. qRT-PCR data demonstrated ENSG00000231789 contributed to nearly all upregulation of PIK3CD-AS2 in LUAD tissues  oligonucleotides specifically silencing PIK3CD-AS2 for xenograft implantation. Our results showed that tumor originating from A549 cells grew rapidly, while LNA-PIK3CD-AS2 treatment generated smaller one  analysis on A549 cells upon PIK3CD-AS2 gene silencing for further mechanism investigation (GSE145018). qRT-PCR and TCGA analysis ruled out the possible effect of PIK3CD-AS2 on its host gene PIK3CD , PMA induced protein 1 (Noxa), p53-upregulated modulator of apoptosis (Puma) and p21 were upregulated, whereas the expression of cyclin E1 (CCNE) was downregulated. The opposite results were shown while PIK3CD-AS2 was overexpressed Fig. . AdditioNext, we confirmed transfection of p53 siRNA partially rescued cell function caused by si-PIK3CD-AS2 Fig. . Similar17. A gene set enrichment analysis (GSEA) using the above RNA-seq data in Fig. To figure out the underlying mechanism of PIK3CD-AS2 blocking p53 activation, we performed RNA pull-down assay and detected a unique band of ~50 kDa to PIK3CD-AS2 Fig. . Using mSubsequently we found that PIK3CD-AS2 only affects the YBX1 protein level but not mRNA level. Silencing PIK3CD-AS2 decreased both YBX1 and phosphorylated YBX1 (p-YBX1) protein levels whereas ectopic overexpression elevated them Fig. . However19. We then found that in the presence of MG132, a proteasome inhibitor, YBX1 protein level was almost rescued compared to si-PIK3CD-AS2 group, suggesting that silencing PIK3CD-AS2 leads to the ubiquitination degradation of YBX1  for 0, 1.5, 3, 4.5, and 6 h, respectively. It is evident that silencing PIK3CD-AS2 shrank the half-life of endogenous YBX1 Fig. , decreasBX1 Fig. . In addiBX1 Fig. . These r21. Besides, PIK3CD-AS2 knockdown did not affect p53 protein stability using CHX or MG132 treatment, respectively  confirmed the combination between YBX1 and p53 Fig. , which iTo evaluate the clinical and translational relevance of PIK3CD-AS2 in LUAD and validated PIK3CD-AS2/YBX1/p53 axis in vivo, we established 12 representative LUAD patient-derived tumor xenograft (PDTX) models, of which tumors originated from six p53 wild-type surgical samples. Consistent with A549 cells in nude mice model, the reduced tumor growth was also observed in LNA knockdown groups, showing a decrease of xenograft tumor volume over a period of one month Fig. . The linP = 0.011) in p53 wild-type patients, which indirectly supported our opinion that wild-type p53 is involved in the regulatory mechanism of PIK3CD-AS2 promoting LUAD progression . None of the patients received anti-cancer treatment before surgery, including chemotherapy or radiotherapy. All samples were confirmed by experienced pathologists and obtained from biobank of Jiangsu Cancer Hospital . All patients had signed informed consent for donating their samples.2. Authentication of cells were verified by STR profiling and mycoplasma contamination of cells were tested using MycoBlueTM mycoplasma detector . Transfections were performed using the Lipofectin reagent (Thermo Fisher Scientific) when cells were seeded at 50–80% confluence, according to the manufacturer’s protocol. For siRNA infection, cells were prepared to 30–50% confluence. Forty-eight hours after transfection, the cells were rinsed twice with phosphate-buffered saline and harvested for next experiments. CHX and MG132 were purchased from MedChem Express .All cell lines  were obtained from the Cell Bank of the Chinese Academy of Sciences . A549, H1299, H1975, PC9, H358 cells were cultured in RPMI 1640 medium , SPC-A1 and HBE1 cells were cultured in DMEM medium , with 100 units/mL penicillin and 100 units/mL streptomycin and 10% FBS  at 37 °C in an incubator with 5% CO36.Predesigned siRNAs for human PIK3CD-AS2 and scramble negative control siRNA were obtained from Thermo Fisher Scientific. YBX1 siRNA (sc-38634), p53 siRNA (sc-29435) and control siRNA were purchased from Santa Cruz Biotechnology . The recombinant PIK3CD-AS2 expression plasmid containing full-length human PIK3CD-AS2 cDNA was constructed by GENEray Biotechnology Shanghai, China). Plasmid pcDNA3 p53 wild-type was a gift from Dr. Yu Cao. The pcDNA-YBX1 overexpression plasmid was prepared by ligating the YBX1 sequence into the BamHI/EcoRI sites of pcDNA3.1(+) vector (Thermo Fisher Scientific) as previously described16. The construction of TMA contained pairs of lung adenocarcinoma tumor tissues and adjacent non-tumor tissues. The expression of PIK3CD-AS2 was detected through RNA CISH using PIK3CD-AS2 specific probe (5′-ACCTGTGCTCTCATCTCTTGCT-3′).The TMA construction method and CISH was performed as our previously reported14. Briefly, cells were fixed in 4% formaldehyde in PBS (pH 7.4). After hybridized with PIK3CD-AS2 specific probe, double-digoxigenin-labeled (DIG-labeled) LNA detection probes , at 55 °C for 2 h, the cells were incubated at RT for 1 h with an anti-DIG-fluorescein monoclonal antibody . Subsequently, cells were counterstained with DAPI and imaged using an AxioVision Zeiss fluorescence microscope.The cellular localization of PIK3CD-AS2 was detected by FISH as our previously reportedThe pcDNA-PIK3CD-AS2 vector and negative control PIK3CD-AS2 antisense plasmid was linearly cut by restriction enzymes. PIK3CD-AS2 and the antisense control was next transcribed and purified in vitro using mMESSAGE mMACHINE kit (Thermo Fisher Scientific) and RNeasy Mini kit , according to the manufacturer’s protocol. After that, we biotinlabeled the 3′ end of PIK3CD-AS2 referencing to the instruction of Pierce RNA 3′ End Desthiobiotinylation Kit (Thermo Fisher Scientific). The next pull-down assay was performed as manual instruction using a Pierce Magnetic RNA-Protein Pull-Down Kit (Thermo Fisher Scientific). Briefly, desthiobiotin-labeled RNA is bound to the Streptavidin Magnetic Beads, and then mixed with whole cell lysates. The RNA-protein complex was isolated from magnetic beads by Biotin Elution Buffer and boiled for mass spectrometry analysis and western blot.RIP experiments were carried out using a EZ-Magna RIP kit  according to the manufacturer’s instructions. Briefly, the cells were extracted and lysed with RIP lysis buffer. Magnetic beads were washed and resuspended in 100 μL RIP wash buffer, followed by incubation with YBX1 antibody for 30 min at room temperature. The beads-antibody complex was then mixed with 900 μL RIP immunoprecipitation buffer and 100 μL cell lysis at 4 °C overnight. Next day, proteinase K was added to each immunoprecipitated products, incubated at 55 °C for 30 min to digest the protein. After centrifuging, 400 μL phenol: chloroform: isoamyl alcohol was used to extract total RNA subjected to further qRT-PCR analysis.TM Kit according to the manufacturer’s protocol (Thermo Fisher Scientific).The subcellular localization of PIK3CD-AS2 was investigated using PARISg at 4 °C. The supernatant was added to the Pierce Spin Column to incubate overnight at 4 °C. Next day, total precipitated protein was eluted and subjected to western blot analysis.The Co-IP assay was performed by Pierce Co-immunoprecipitation kit according to the manufacturer’s instructions (Thermo Fisher Scientific). In brief, YBX1  and p53  antibody was incubated with AminoLink Plus Coupling Resin for 90 min at room temperature, respectively. Meanwhile, Cell lysate was prepared in IP buffer and centrifuged for 10 min at 13,000 × Western blot was performed according to the routine protocol. Cells were washed twice in chilled PBS and lysed. Supernatants derived from cell extracts were separated on 10% SDS-PAGE gel, followed by transferred to a PVDF membrane. After blocking in 5% nonfat dry milk, the PVDF membrane was incubated with diluted primary antibodies. The information of primary antibodies is listed in Supplementary Table Total RNA was extracted from tissues and cells using TRIzol reagent (Thermo Fisher Scientific) and qRT-PCR was performed to target RNA using Fast SYBR® Green Master Mix (Thermo Fisher Scientific) on a QuantStudio 6  as directed by the manufacturer. Forward and reverse primer sequences for specific genes listed in Supplemental Table 3 cells were seeded to each well of E-Plate and incubated at 37 °C with 5% CO2 with proliferation monitoring every 15 min for at least 90 h.Cell proliferation was detected by real time xCELLigence analysis system (RTCA) according to the manufacturer . After transfected with siRNA, expression plasmid or scramble control, respectively, 5 × 105 cells were fixed in ice-cold 70% ethanol before staining with propidium iodide (PI). The proportion of each phase of the cell cycle was calculated by FACS analysis equipped with Cell Quest software . Cell apoptosis was analyzed by an FITC annexin V detection kit with PI according to the manufacturer’s protocol. Briefly, cells were suspended in 1× binding buffer at a concentration of 1 × 106 cells/mL. The cell suspension (100 μL) was then transferred to a flow meter tube, mixed with 5 μL FITC annexin V and 10 μL PI, and incubated for 20 min at RT in darkness. Samples were analyzed by flow cytometry within 1 h.For cell cycle distribution analysis, 1 × 10Cells were cultured in 96-well plates in complete media until 80–90% confluent and then treated with 50 μM 5-ethynyl-2′-deoxyuridine (EdU) for 6 h to measure proliferation according to the manufacturer’s instructions using an EdU DNA Cell Proliferation Kit .4 cells were seeded on the upper Matrigel-coated chambers (8-μm pore) with serum-free RPMI 1640 medium, the lower wells were filled with 600 μL medium containing 10% FBS. After the chambers were incubated at 37 °C in an incubator with 5% CO2 for 24 h, the invasiveness was calculated by the number of cells invaded through the chamber and adhered to the bottom of the membrane. For wound healing assays, cells were transfected with PIK3CD-AS2 siRNA or control, and the wounds were made using a pipette tip. The cells were cultured in low-serum medium (0.1% FBS), and pictured after 36 h of wounds.For invasion assay, 4 × 106 cells were engrafted into the left and right armpits of six male BALB/C nude mice, which subsequently receiving two injections of LNA-PIK3CD-AS2 or negative control the first week, spaced two days apart, and weekly injections of the treatment thereafter. Mice were sacrificed after six weeks, and tumor size and weight were measured. Frozen or paraffin-embedded tumor samples were analyzed using qRT-PCR or immunohistochemistry, respectively. PDTX model was performed as previously described16. Primary LUAD tumor was cut into 1 mm3 fragments in 0.1 mL 50% Matrigel Basement Membrane Matrix (BD Biosciences) and directly implanted into the subcutaneous space. After second generation, PDTX tumors were received genomic and histological examination. Mice with approximately 200 mm3 tumor were randomized into experimental group, giving LNA-PIK3CD-AS2 injection (1.5 mg/kg) twice a week, or scramble control with same dosage and treatment frequency. Tumor size was measured every week using calipers. The mice were euthanized after one month, and the tumors were excised and snap-frozen or paraffin embedded for further analysis.The animal care and the study procedures were approved by Animal Experimentation Ethics Committee of Nanjing Medical University (2015–174). Five-week old NOD/SCID mice were purchased from Vital River Laboratories , maintained in facilities at the center of animal experiments of Nanjing Medical University. 5 × 10Five micrometer sections from formalin-fixed paraffin-embedded tumor tissues were deparaffinized, rehydrated, and rinsed in distilled water. Following antigen retrieval in boiling 0.1 M citrate (PH 6.0) buffer for 10 min, the slides were then probed with antibodies against p53, YBX1, p-YBX1 and Ki-67. The detail of antibodies is listed in Supplementary Table t-test and paired t-test. The association between clinical characteristics and PIK3CD-AS2 expression was analyzed by the chi-square test. Survival curves were plotted using Kaplan–Meier method, and differences between survival curves were tested using the log-rank test. Statistical significance was considered with a P value less than 0.05. The sample size for patients and animal model were determined as previously described16.Statistical analysis was carried out using GraphPad Prism and SPSS 20.0 . Normal distribution of the data was tested. Data were presented as means ± SD. Differences between groups were assessed by two-tailed Student’s Supplementary figure legendsSupplementary table 1Supplementary table 2Supplementary table 3Supplementary figure 1Supplementary figure 2Supplementary figure 3Supplementary figure 4Supplementary figure 5Supplementary figure 6Supplementary figure 7Supplementary figure 8


To ensure that a structure will last throughout its service life, repairing reinforced concrete entails, among others, correctly marking off the area affected by aggressive agents that may deteriorate both the concrete and the steel. Chloride, the most damaging source of reinforcement corrosion, may diffuse to a greater or lesser distance from the surface depending on the ease of penetration. In this study, we calibrated a handheld X-ray fluorescence analyser (hXRF) and used it to quantify the chloride concentration in cement-based materials. The findings were verified against a series of samples of known concentration to establish a suitable correction factor. Chloride ions were quantified precisely and accurately with the hXRF instrument, and we calculated a correction factor of 1.16. The instrument and the information recorded were used to quantify the chloride ion content in different parts of an existing structure. The analyser identified apparently healthy areas that could, nonetheless, pose oxidation problems in the near future due to significant chloride concentration. Chloride quantification data at different depths can be used to draw diffusion or penetration profiles and to determine whether ion concentration around the reinforcement is within the recommended limits. The method developed can be applied in situ to quickly locate the most critical areas. A number of factors can shorten the service life of reinforced concrete structures due either to concrete deterioration or steel reinforcement corrosion, the latter predominantly induced by the presence of chloride ions.Reinforced concrete is damaged by chloride ions due to their capacity to activate the passive layer that protects the steel, exposing the metal to oxidation ,2,3. SteAlthough many mechanisms may be involved in chloride ingress in concrete, diffusion is widely agreed to be the most prominent. Ingress and related service life models have been developed from empirical variations based on Fick’s laws ,10.The basis for normalising chloride quantification is the Volhard method , in whicX-ray fluorescence (XRF) spectrometry involves measuring secondary or fluorescent energy emitted when a sample is radiated with high energy X-rays (wavelength from 0.01 to 10 nm). Secondary X-ray emission is characteristic of the atoms in a sample, making this a useful technique for the detection and quantification of elemental concentrations. The European standard  for the −]/[OH−] ratios of 0.12 to 3.0 to free chloride content of 0.03–4% [The is a wide range of threshold values above which chloride ions are deemed to be detrimental to reinforcement, from [Cl 0.03–4% ,21,22,23 0.03–4% ,25,26. T 0.03–4%  defines  0.03–4%  also citTechniques are now in place for the non-destructive, in situ determination of reinforcement corrosion current density in concrete structures . Such teIn this paper, we describe the calibration and adaptation of a handheld X-ray fluorescence analyser to quantify chloride ions in mortar or concrete samples and its application to the in situ assessment of structures. The threshold chloride concentration cited in the existing legislation were taken as a criterion for marking off the areas affected by chloride ions. We conclude with the description of a case study in which the hXRF supported structural analysis and repairs by determining the chloride concentration at different points on a corroded structure.The first stage of this study consisted of the laboratory calibration of an instrument to quantify chloride ions and, subsequently, validating the chloride concentration findings against the results of potentiometric titration of the samples . Acid-sopR), i.e., by generating a 30 to 100 s galvanostatic pulse to induce quasi-stability. The reference for the corrosion current density readings delivered by the corrosimeter is the polarised rebar-bearing area within the sensor range. The pR was calculated directly as ΔE/ΔI multiplied by the rebar-bearing area, the technique most commonly used to measure corrosion current density in reinforcement steel. The GECOR’s Cu/CuSO4 sensors  afforded the instrument stability and ruggedness for field use [Then, the calibrated instrument was used as a supporting tool to diagnose the causes of deterioration in a reinforced concrete structure and as an objective method for marking off the areas in need of rehabilitation and repair. The criterion applied was the 0.6% chloride content threshold set out in the applicable legislation, in this case the Spanish structural concrete code. The degree of corrosion in the reinforcing steel analysed was determined with a GECOR corrosimeter , an instrument that operates on the linear polarisation principle with current confinement to measure polarisation resistance   operatinThe test setup included a workbench on which the hXRF analysed the samples under radiation exposure-free conditions in which the readings could be taken without any actual hand contact with the instrument while in operation. The workbench was connected to a computer to monitor the tests. In on-site testing, both devices were powered by an external generator.The concrete samples were removed from the structure analysed with a drill bearing a special concrete bit . The dusThe field electrochemical readings taken with the GECOR device ,33 inclupR) to calculate the corrosion current density according to the Stern–Geary equation (see Equation (1)) with a constant B value of 26 mV. The method used by the GECOR is the “modulated current confinement” where the sensor uses two concentric counter electrodes, the external one called the “guard ring” which confines the galvanostatic signal to a determined area [corri values is given in Then, corrosion current density, which is directly related to reinforcement section loss, was determined in the areas found to be most severely affected. The GECOR device measures the polarization resistance  at a 90.0% confidence interval. Taking the end-point potentiometric value as an accurate measure, the calibration factor for hXRF was found to be 1.16. In other words, the chloride concentration in the structure was equal to the instrumental reading multiplied times 1.16.The end-point potentiometric quantification findings for chloride ions  are compThe inspection findings for the concrete structure studied are discussed below.3 of concrete and, in this case study, a closer estimate would be around 250 to 300 kg/m3, the value adopted for the calculations was 275 kg/m3. Applying the 0.6% (cement weight) chloride concentration threshold set out in the existing legislation yielded a value of 900 ppm as the critical chloride concentration by sample weight.As noted earlier, the handheld instrument readings were expressed as chloride concentration by total sample weight, whereas in the legislation the concentration is expressed as a percentage of cement weight. Consequently, when concrete or mortar dosage is unknown, chloride concentration by cement weight must be calculated from assumed values. Given that the cement content in reinforced concrete for structural members usually ranges from 250 to 350 kg per m3 of concrete. The points analysed on the girder are marked on the photograph in The corrosion potential and resistivity values data needed to map areas of the element with different degrees of corrosion are given in The corrosion potential and the resistivity are used as preliminary measures to delimit possible areas affected by corrosion, due to its ease and speed in their implementation. They are qualitative measurements that locate areas with a high probability of corrosion  and critical corrosion potential (Ecrit = −274 mV). The safe area lies between the values <Ccrit and >Ecrit.The findings revealed the existence of points (in the shaded area in corrI > 0.1 µA/cm2). The discrepancy may be attributable to the prevalence of high resistivity over corrosion current density [Corrosion current density, also measured in the area studied, revealed activation at many but not all of the points at issue  laid down in the legislation applied, a value of 900 ppm was established as a conservative threshold above which chloride ion-mediated corrosion may be deemed to be underway or potentially underway. The methodology described is equally applicable for use with other standards or codes with different thresholds for calculating the respective chloride concentration threshold.This study discusses the use of a handheld X-ray fluorescence analyser to support analysis in repairs, where the primary cause of deterioration is reinforcement steel oxidation due to the presence of a high chloride concentration. Such instruments furnish speedy and accurate on-site information on ion concentration in concrete that can, then, be applied to more accurately define the areas in need repair.The most prominent conclusions drawn from the present study are listed as follows: