Up to 80% of antibiotics are prescribed in the community. An assessment of prescribing by indication will help to identify areas where improvement can be made. A point prevalence audit study (PPAS) of consecutive respiratory tract infection (RTI) consultations in general practices in 13 European countries was conducted in January–February 2020 (PPAS-1) and again in 2022 (PPAS-4). The European Surveillance of Antibiotic Consumption quality indicators (ESAC-QI) were calculated to identify where improvements can be made. A total of 3618 consultations were recorded for PPAS-1 and 2655 in PPAS-4. Bacterial aetiology was suspected in 26% (PPAS-1) and 12% (PPAS-4), and an antibiotic was prescribed in 30% (PPAS-1) and 16% (PPAS-4) of consultations. The percentage of adult patients with bronchitis who receive an antibiotic should, according to the ESAC-QI, not exceed 30%, which was not met by participating practices in any country except Denmark and Spain. For patients (≥1) with acute upper RTI, less than 20% should be prescribed an antibiotic, which was achieved by general practices in most countries, except Ireland (both PPAS), Croatia (PPAS-1), and Greece (PPAS-4) where prescribing for acute or chronic sinusitis (0–20%) was also exceeded. For pneumonia in adults, prescribing is acceptable for 90–100%, and this is lower in most countries. Prescribing for tonsillitis (≥1) exceeded the ESAC-QI (0–20%) in all countries and was 69% (PPAS-1) and 75% (PPAS-4). In conclusion, ESAC-QI applied to PPAS outcomes allows us to evaluate appropriate antibiotic prescribing by indication and benchmark general practices and countries.  In January 2022, the first joint report on antimicrobial resistance surveillance from the European Centre for Disease Prevention and Control (ECDC) and World Health Organization (WHO) Regional Office was published and provided a pan-European overview of the extent of antibiotic resistance (ABR) in Europe . ABR is In 2007, ESAC published a set of 12 relevant evidence-based disease-specific quality indicators (QI) for outpatient antibiotic prescribing ,9,10,11.In 2020, a prospective point prevalence audit survey (PPAS) of consultation and management characteristics of patients presenting to their general practitioner (GP) with a respiratory tract infection (RTI) in 16 European countries was initiated . In JanuA total of 3,618 consultations were recorded for PPAS-1 (range 132–390) and 2655 (range 198–233) in PPAS-4 . The meaAntibiotics were prescribed in 30% of consultations in PPAS-1 and 16% in PPAS-4 with wide variations between countries. The lowest prescribers were Belgium, Denmark, and Croatia in both PPAS-1 and PPAS-4 .When prescribing for RTI, overall about 30% is prescribed a broad-spectrum penicillin, 15% a narrow-spectrum penicillin, 21% a macrolide, 19% amoxicillin-clavulanic acid, and quinolones and tetracyclines are prescribed around 5% each . This diESAC QI values were calculated for each country and for the overall total. The percentage of adult patients with bronchitis who receive an antibiotic should, according to the QI, not exceed 30%. This QI was not met by any country, except for Denmark and Spain, in both PPASs. For patients (over one year of age) with acute upper RTI, less than 20% should be prescribed an antibiotic, which was achieved by most countries, except Ireland in both PPAS, Croatia (PPAS-1), and Greece (PPAS-4). In the same countries, antibiotic prescribing also exceeded the acceptable range of 0–20% for acute or chronic sinusitis. For pneumonia in adults, prescribing is acceptable in 90–100% of the cases, and this is lower in many countries. However, the number of patients in each country with pneumonia was relatively low (between 1 and 26). Prescribing for tonsillitis in the over-one-year age group exceeded the acceptable range of 0–20% for all countries and was 69% and 75% for PPAS-1 and PPAS-4, respectively .An increase in prescribing for adult patients with acute bronchitis was observed between PPAS-1 and -4 while antibiotic prescribing for patients with acute upper RTI, cold, or sinusitis in both groups (over one year of age and adults) fell. For acute bronchitis in adults, this increase was mainly due to an increase in Georgia, Romania, the UK, and to a lesser extent the Netherlands, while Germany, Denmark, Croatia, and Ireland showed a decrease. The decrease in prescribing for acute upper RTI, cold, or sinusitis was mainly due to decreases in Croatia, Romania, Denmark, and Spain. The UK showed increases in the over-one-year and adult age groups for acute upper RTI, cold, or sinusitis. Quinolone prescribing should not exceed 5% as the antibiotic of choice for bronchitis. Only in Greece (PPAS-1 and -4) and Romania (PPAS-1) was this exceeded. For two consultations (Ireland and Romania), quinolones were prescribed for acute upper RTI in PPAS-1 and for five consultations  in PPAS-4. Quinolones were occasionally prescribed for sinusitis  and tonsillitis (Romania). For pneumonia, quinolones were prescribed in Spain (3), Greece (4), and the Netherlands (1) in PPAS-1, while in PPAS-4, one quinolone prescription was issued during a Greek and a Polish consultation.PPAS offers general practices in countries and a unified protocol to record RTI consultations, which allows comparisons of participating general practices between and within countries. The percentage of consultations with suspected bacterial aetiology dropped and so did the percentage of antibiotics prescribing. If there was prescribing, nearly half (45%) of the prescriptions were for a penicillin, but macrolide, amoxicillin-clavulanic acid, and quinolones remain popular choices. QI in relation to bronchitis and tonsillitis are generally not met, but overall better results were observed for acute upper RTI, sinusitis, and pneumonia.There do seem to be differences between participating general practice countries in the type of patients consulting with up to 50% of patients with comorbidities in some countries. The differences in the management of patients as well as antibiotic prescribing may be explained by differences in patient consulting behaviour between countries . PatientMore consultations were considered of bacterial aetiology in PPAS-1 (26%) compared to PPAS-4 (12%), also reflected in the proportion of antibiotic prescriptions (30% v 16%). Symptoms recorded during PPAS-1 and PPAS-4 were broadly similar within participating general practices in countries. Whether patients and GPs were more accepting of a viral diagnosis (and thus of not prescribing antibiotics) since the COVID-19 pandemic cannot be concluded from the results but may be a positive unintended consequence of the pandemic. A decrease in antibiotic prescribing since the pandemic has previously been described but did not persist . ResultsIn general, when the decision to prescribe an antibiotics is made, penicillin is recommended, in a particular narrow spectrum (J01CE). In many countries GPs still prescribe antibiotics, which are not recommended, such as macrolides and amoxicillin-clavulanic acid. This is generally due to non-adherence to guidelines and, in some countries, also due to availability of (narrow-spectrum) penicillin . Education on the use of narrow-spectrum antibiotics could be considered for campaigns to improve the choice of antibiotic. Macrolides remain commonly prescribed for the treatment of RTIs, but the development of widespread macrolide resistance has limited their use . In addiWhen considering opportunities for antibiotic stewardship in general practice, targeted actions would have the most impact on antibiotic prescribing for tonsillitis. Around 70% of tonsillitis consultations result in an antibiotic prescription, when the acceptable range is between 0–20%. Much improvement can be made. Similarly, most countries could also improve the quality of antibiotic prescribing for bronchitis, with antibiotics prescribed during half of the consultations where the acceptable range is 0–30%. In particular, Ireland shows an excessive prescribing of antibiotics for upper RTI and sinusitis, and additional interventions should aim to reduce prescribing for these conditions, which is possible considering that other countries do not exceed the acceptable range. Differences between PPAS-1 and -4, overall as well as within participating general practices in countries, show that the ESAC QI are sensitive enough to pick up changes. Future PPASs together with national and international antibiotic strategies (ABS) will show if and where campaigns are working and may also provide evidence of what works, if countries use different styles of interventions and awareness campaigns. Interventions targeted at GP have shown successes and updates or adjustments to focus these campaigns in the light of our findings may be timely ,28,29. AThe main strength was the existence of the PPAS infrastructure and yearly monitoring of RTI in general practice with a pre-defined (standardised) set of questions. Most participating practices have multiple GPs contributing to the diversity in diagnosis and prescribing. This allows for prospective data collection and direct comparisons between participating general practices in countries, in particular when assessing country-specific guidelines. The recording of both antibiotic prescribing as well as its indication allows direct comparisons of the quality of prescribing between and within countries. The main limitation also lies in the existing infrastructure, which consisted of 2 to 10 general practices in each country, and even though multiple GPs may have contributed, the participating practices may not represent all general practices, nor is a comparison with other practices within each country possible. Participating practices may already have an interest in antibiotic prescribing and/or RTIs, which could result in better prescribing than could be expected with a larger sample of practices. However, as we can see changes over time within countries, the ESAC QI are sensitive enough to pick up small changes. When looking at individual countries and further breaking it down into the different QIs, the number of consultations decrease, and small changes or occasional prescribing seem to have a large effect. As PPAS is repeated yearly, timely publications of its results may encourage more countries, general practices, and GPs to participate and add to the generalisability of its results.In conclusion, ESAC QI provide a high-level snapshot, which, when applied to PPAS outcomes, benchmark participating general practices in countries against each other. Even though differences remain, the similarities in poor outcomes (for tonsillitis and bronchitis) identified clear targets for antibiotic stewardship.A prospective PPAS of consultation and management characteristics of patients with RTIs in 19 European countries was conducted using a pre-defined set of questions . GPs anoParticipating general practices in countries involved in the repeated PPAS and from which a full dataset was available for PPAS-1 and -4 were Belgium, Croatia, Denmark, Georgia, Germany, Greece, Ireland, Moldova, the Netherlands, Poland, Romania, Spain, and the United Kingdom (UK) . ArmeniaAs only consultation details were recorded and no personally identifiable information was collected, informed consent was not necessary. Each country obtained ethical approval or received a waiver for full ethical submission for the PPAS.In PPAS-1 and -4, GPs were asked to sequentially register consultations of patients of all ages with either sore throat (symptom duration < 14 days) and/or cough (symptom duration < 28 days) and to exclude consultations of patients with only nasal or ear symptoms . PPAS-4 Free responses for working diagnosis were analysed and coded according to the ESAC QI. The indicators are applied to consultations with patients within certain age ranges and with specific diagnoses and provide an acceptable percentage range of patients who are prescribed an antibiotic . The ESAoDue to the focus on respiratory symptoms and the exclusion of those with solely ear symptoms, for ESAC Quality Indicators 3 (focusing on urinary tract infections) and 6 (focusing on otitis media) values could not be calculated.oESAC QI for upper RTI and sinusitis were combined with the working diagnosis “cold,” as this is how it was presented on the PPAS-4 survey form . For theoThe PPASs were designed for a broader application than to evaluate the ESAC quality indicators and the following adjustments were made:IBM SPSS (Version 27) and R (version 4.1.0) were used to conduct the analysis and generate graphs.


Sulfate attack is one of the main factors affecting the durability of concrete structures. In recent years, multi-walled carbon nanotubes (MWCNTs) have attracted the attention of scholars for their excellent mechanical properties and durability performance. In this paper, the influence of sulfate attack and dry–wet cycles on the performance of multi-walled carbon nanotube–lithium slag concrete (MWCNT-LSC) with varied MWCNT content  and varied water–cement ratios  were investigated. In addition, scanning electron microscopy (SEM) and X-ray computed tomography (CT) tests were conducted to analyze the microstructure and pore structure of the concrete. The results showed that concrete incorporated with MWCNTs could effectively mitigate sulfate attack. The resistance to sulfate attack of concrete was negatively related to the water–cement ratio when the dry–wet cycle was fixed. The MWCNT-LSC showed the best compressive strength at the water–cement ratio of 0.35 and 0.10 wt.% MWCNTs. The SEM test results showed that the MWCNTs filled the pores and cracks within the specimen and formed bridges between the cracks, enhancing the resistance to sulfate attack. The CT test results also showed that the addition of MWCNTs could reduce the porosity of concrete, refine the pore size and inhibit the generation and development of cracks, thus optimizing the internal structure of concrete and improving its resistance to sulfate attack. Aggressive salts in the environment are a significant cause of the deterioration of concrete properties. In particular, sulfate attack is one of the main factors affecting the durability of concrete ,3,4,5,6.operties ,9,10,11.Nanoparticles of appropriate size can fill the cementitious pores of cement hydration products and reduce the amount of cement-based materials . This coResearch on carbon nanotube–cement matrix composites is still exploratory ,30. SchoStudies on the effect of sulfate attack on MWCNTs concrete were still minimal. This paper investigated the effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties and microstructure of lithium slag concrete (LSC) during sulfate attack and drying–wetting cycles. The deterioration pattern of lithium slag concrete under sulfate attack was investigated by studying the changes in morphology, compressive strength, and mass loss of multi-walled carbon nanotube–lithium slag concrete. The microstructure of multi-walled carbon nanotube–lithium slag concrete (MWCNT-LSC) was analyzed by scanning electron microscopy (SEM). The internal porosity, pore size distribution, sphericity, and compactness were examined using X-ray computed tomography (CT) images.3 and a specific surface area of 417 m2/kg. The main chemical composition of cementitious material is shown in 3 and a fineness modulus of 2.8. The coarse aggregate was continuously graded gravel with a 5–20 mm particle size and an apparent density of 2687 kg/m3. The water-reducing agent was a high-performance polycarboxylic acid water-reducing agent. The test water was taken from municipal tap water. The multi-walled carbon nanotubes chosen for this experiment were prepared by Chengdu Jiacai Technology Co., Ltd. , following the CVD process. The physical parameters are shown in The cementitious material used in this study was a composite of P⋅O 42.5 ordinary Portland cement (OPC) and lithium slag (LS), which was taken from the Urumqi lithium salt plant, dried and ground, and put into the experiment with a density of 2.48 g/cmIn total, 12 groups of MWCNT-LSC with different specimens were prepared, where the water–cement ratio (W/C) was varied as 0.35, 0.40, and 0.45, and the content of MWCNTs was 0 wt.%, 0.05 wt.%, 0.10 wt.%, and 0.15 wt.% of the cement mass; the mix proportions are shown in According to GB/T 50082-2009 , the conP (N) is the peak load and A (mm2) is the pressure area of the specimen.W (%) is the mass loss rate of concrete after erosion, G0 (g) is the initial mass of concrete before erosion, and iG (g) is the i-th measured mass of concrete after erosion.The specimens were tested for compressive strength and quality at the end of every 30 dry–wet cycles. According to standard GB/T 50081-2019 , the comAn SU8010 scanning electron microscope from Hitachi, Tokyo, Japan, was used to observe the microstructure of MWCNT-LSC at different numbers of dry–wet cycles. The specimen size of the concrete test was about 8 mm, and the non-observed surface was polished and glued to the conductive glue of the disc, followed by gold spraying.The pore structures of the MWCNT-LSC specimens were investigated using X-ray computed tomography technology (CT). The concrete utilized in this CT test was scanned using Y.CT COMPACT equipment  and (4). The results are shown in The compactness and sphericity were used to measure the regularity of the pores. The closer the two values were to 1, the greater the resemblance of the pore with a regular circle. According to This study studied the mechanical and durability properties of multi-walled carbon nanotube–lithium slag concrete (MWCNT-LSC) after sulfate dry–wet cycles. Microstructure and pore structure were analyzed based on SEM and CT test results. The main conclusions are summarized as follows:(1) MWCNTs significantly increased the compressive strength of LSC. The compressive strength increased and then decreased with the increase in MWCNT content. The LSC compressive strength reached the maximum value of 71.3 MPa when the water–cement ratio was 0.35 and the MWCNT content was 0.10 wt.%. Compared with the specimens without MWCNTs, the compressive strength increased by 4.7%.(2) A moderate amount of MWCNTs enhanced LSC resistance to sulfate attack after sulfate dry–wet cycles. After 150 sulfate dry–wet cycles, most of the MWCNT-LSC specimens showed no significant changes in appearance. The compressive strength tended to increase and decrease as the number of sulfate dry–wet cycles increased, but the mass loss rate tended to decrease and then increase.(3) An SEM test showed that MWCNTs improved the resistance of concrete to sulfate attack by filling pores and forming bridges in cracks within the concrete, hindering crack expansion.(4) A CT test showed that the addition of MWCNTs could effectively reduce the porosity of the samples. In addition, MWCNTs could optimize the pores and improve the sphericity and compactness.(5) The above conclusions provide references for further research on MWCNT-LSC and its potential applications in construction. In addition, it should be noted that more in-depth and refined studies on MWCNT-LSC exposed to different aggressive environments are required in the future.


The Brix% of ‘TY Chika’ was highest on average (9.5%) and had a large difference from 6.2 to 14.2% among the samples. Data distribution of cherry tomato groups such as ‘TY Chika’ and M&S cherry tomatoes was closer, indicating a roughly linear correlation between fresh weight and Brix%.The use of non-destructive commercial near-infrared (NIR) spectroscopy to estimate Brix% was verified using all samples of cherry tomato ‘TY Chika’, currant tomato ‘Microbeads’, and the M&S or market-purchased and supplemental local source tomatoes. Additionally, the relationship between fresh weight and Brix% of all samples was examined. These tomatoes had a diversity of cultivars, growing methods, harvest timing, and production locations and varied widely from 4.0% to 14.2% for Brix% and 1.25 g to 95.84 g for fresh weight. Regardless of the diversity of all samples, it was revealed that the refractometer-based Brix% (y) was practically estimated from the NIR-derived Brix% value (x) using a relationship of y = x (RMSE = 0.747 Brix%) after only a one-time calibration for the NIR spectrometer offset. An inverse relationship between fresh weight and Brix% could be modeled using a hyperbolic curve fit, and the model showed an R The sugar content of tomato fruits varies depending on cultivars, growing methods, and harvest timing ,2,3. FruSome varieties of cherry tomatoes have very high sugar concentrations . AdditioIn this paper, therefore, the relationship between Brix% values and NIR values was examined for cherry and currant tomatoes in addition to medium tomatoes with larger sizes; the tomatoes had different cultivars, growing methods, harvest timing, production locations, and sizes. Additionally, the relationship between fresh weight and Brix% was modeled.Solanum lycopersicum L. cv. TY Chika, which produces red-colored fruits and currant tomato plants, Solanum pimpinellifolium L. cv. Microbeads, which also produce red-colored fruits, were tested in this study. Plants were grown hydroponically in a greenhouse. Cherry tomato ‘TY Chika’ and currant tomato ‘Microbeads’ were planted on 11 November 2021 and 2 November 2022, respectively. Ripe fruits were harvested from plants. Harvests were made from 10 plants for ‘TY Chika’, and 8 plants from ‘Microbeads’. Additionally, tomatoes from markets and supplemental local sources  were also measured. Production area and growing methods vary for market-purchased tomatoes. The M&S tomatoes were also separated into two categories: (1) cherry tomatoes and others or (2) non-cherry tomatoes. We noted that growing methods were unknown for market-purchased tomatoes, and production locations were not identified for some commercial products. All M&S tomatoes were red in color.Cherry tomato plants, −1. Tomato plants were grown on high-wire systems. Hydroponic solution was provided through arrow drippers to rockwool blocks. Further specifications of the smart greenhouse can be found in Omasa et al. (2022)  sIn this study, the nondestructive commercial near-infrared (NIR) spectroscopy to estimate Brix% was verified using all samples of cherry tomato ‘TY Chika’, currant tomato ‘Microbeads’, and M&S tomatoes. Additionally, the relationship between fresh weight and Brix% of all samples was examined. These tomatoes had a diversity of cultivars, growing methods, harvest timing, and production locations and varied widely from 4.0% to 14.2% for Brix%. Regardless of the diversity of samples, it was revealed that the refractometer-based Brix% (y) was practically estimated from the NIR-derived Brix% value (x) using a relationship of y = x (RMSE =0.747Brix%) after only a one-time calibration for the NIR spectrometer offset.2 of 0.809 except for ‘Microbeads’. Cherry tomato ‘TY Chika’ fruits showed the highest Brix%. The Brix% of ‘TY Chika’ was 9.5% on average and had a large difference from 6.2 to 14.2% among the samples. Data distribution of cherry tomato groups such as ‘TY Chika’ and M&S cherry tomatoes was closer, indicating a roughly linear correlation between fresh weight and Brix%. For currant tomato ‘Microbeads’, the fresh weight and Brix% did not change much compared with ‘TY Chika’ and formed a cluster. Other types of tomatoes in the M&S showed a long tail on the right-hand side of the figure, showing similar Brix% at different fresh weights. Overall, a hyperbolic curve fit determined in this study explained the relationship between fresh weight and Brix% well, except for currant tomato ‘Microbeads’.An inverse relationship between fresh weight and Brix% can be modeled using a hyperbolic curve fit, and the model showed an R


Here, we present a protocol for the construction of a hierarchical host-guest supramolecular self-assembly system in water. We describe steps for determining the binding levels and capturing the morphologies of hierarchical self-assembly. We detail procedures for using UV-vis spectra, nuclear magnetic resonance spectra, scanning electron microscopy, and transmission electron microscopy for the assembly. This protocol is useful for analyzing the detailed chemical structure and morphological variation of hierarchical host-guest supramolecular self-assembly systems.For complete details on the use and execution of this protocol, please refer to Chen et al. (2022).  •Detailed protocol for determining the binding levels of hierarchical self-assemblies•Detailed protocol for molecular binding structures of hierarchical self-assembly by NMR•Detailed protocol for capturing the morphologies of hierarchical self-assemblies Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. Here, we present a protocol for the construction of a hierarchical host-guest supramolecular self-assembly system in water. We describe steps for determining the binding levels and capturing the morphologies of hierarchical self-assembly. We detail procedures for using UV-vis spectra, nuclear magnetic resonance spectra, scanning electron microscopy, and transmission electron microscopy for the assembly. This protocol is useful for analyzing the detailed chemical structure and morphological variation of hierarchical host-guest supramolecular self-assembly systems. This protocol describes the detailed steps for identifying a hierarchical host-guest supramolecular self-assembly system in water via UV-vis spectra, NMR spectra, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) according to the publication from Chen et al.Timing: 1.5–2 h1.a.1 M HCl solution is prepared by diluting concentrated HCl solution (12 M) with filtered deionized water.b.1 M NaOH solution is prepared by dissolving required amount of NaOH solid with filtered deionized water.c.The deionized water is regulated to the required pH value.Preparation of deionized water in different pH that is regulated by diluted aqueous HCl and NaOH as test required.Note: If the pH value of water does not affect the test result, please just start test from step 2. For NMR tests, deuterated reagents such as D2O, DCl, NaOD are used for the preparation.2.a.The powder of the guest molecule is added into vessel, and further dissolved or dispersed with water prepared from step 1.b.The vessel with aqueous solution of the guest molecule is treated by ultrasound about 1 or 1.5 h to guarantee the complete dissolution of the guest molecule.Preparation of aqueous solution of the guest molecule.Note: 1. If the guest molecule is poorly water-soluble, tiny amount of organic solvent can be used to help the dissolution of guest molecule in water. But the addition of organic solvent is suggested not exceeding 1% (v/v). 2. All vessels should be washed carefully by filtered deionized water and dried in a constant temperature .Timing: 1–3 h3.a.In a vessel, the host molecule is dissolved by deionized water that prepared from step 3.b.The vessel with aqueous solution of the host molecule is treated by ultrasound about 1 or 1.5 h to guarantee that the host molecule dissolves well.Preparation of aqueous solution of the host molecule.Note: if the host molecule is not well water-soluble, please see step 4.4.a.In a vessel, the guest molecule  and host molecule are dispersed with water prepared from step 3.b.The vessel with the above-mentioned aqueous dispersion is put into ultrasound equipment about 2 or 2.5 h to make sure the sufficient dispersion of the host and guest molecules.Preparation of the host molecule aqueous dispersion with trace amount of guest molecule.Note: 1. If there is still insoluble solid in the sample, increase the temperature and prolong the ultrasonic time. 2. The host molecule aqueous solution or dispersion prepared in this step should be used as soon as possible to avoid the influence of precipitation on the experimental results.CRITICAL: Hydrochloric acid is highly irritating and corrosive to eyes, skins, and the respiratory system. Handle it under a chemical fume hood, wear gloves, eye goggles and appropriate personal protective equipments.CRITICAL: NaOH solid and NaOH aqueous solution is highly irritating and corrosive to eyes, skins, and the respiratory system. Handle it under a chemical hood wearing gloves and protective eye goggles.Timing: 2–4 h1.Dilute guest molecule aqueous solution according to the experimental requirements.Note: The recommended concentration of guest molecule in water is at least 4 × 10–5M.2.Setting parameters of the UVProbe software are as follows:This section describes the variation of the UV-vis spectra of guest molecule by gradually adding host molecule, which can reveal changing of the assembly state in different binding levels. A UV-vis spectrophotometer system is required in this section A.1.DilutMeasuring mode is absorbance;Slit width is 2.0 nm;Scan wavelengths range from 250 nm to 800 nm;Scan speed is fast;Optional: Control the test temperature at a constant temperature  according to experimental requirements  and rotating-frame Overhauser effect spectroscopy (ROESY).  All vessels should be washed with filtered deionized water. (2) The concentration of hierarchical host-guest supramolecular self-assemblies in water should be higher than the critical aggregate concentration  for about one night.19.Fix the wafer on the metal sample stage by double-sided conductive adhesive B.20.Put the sample stage into specimen storehouse following with vacuuming.Note: The SEM instrument is very expensive. Please make sure you are qualified to operate it.21.Find the self-assemblies from the sample in low magnification with original voltage carefully and patiently.Note: In this step, patience is very important.22.Once you find the self-assemblies in proper morphology, please increase the magnification, turn down voltage , focus on the self-assemblies, and take photos as soon as possible.Note: Don't stay at the same place for a long time to avoid destroying the sample by electron beam  Attention again: All vessels should be washed with filtered deionized water. (2) For TEM test, the concentration of sample should be no higher than 8 × 10–4M.25.The solution of hierarchical host-guest supramolecular self-assemblies should be left standing for more than 1 h before being dropped into gilder TEM grids, see Note: 1. Put a filter paper under the gilder TEM grids to keep the sample on the grids clean. 2. Normally, a drop (5–10 μL) of solution is enough for one gilder TEM grid. 3. Don’t mistake the front and back of the gilder TEM grid, that is, the side of gilder TEM grid with carbon film should be put face to you.CRITICAL: When handling the grid, be careful of the pipette tips and the tweezers to avoid damaging the grid surface.26.Set the gilder TEM grids with sample in the dark at a constant temperature  for about one night.27.The grid should be put into a standard TEM holder, followed by placing the TEM holder into specimen storehouse.Note: The TEM instrument . However, NMR spectra requires higher concentration (at least 1 × 10–3 M) in D2O for clear peaks. The intermolecular structure and interactions between host and guest molecules can only be obtained from NMR results, which is the foundation to demonstrate the formation of hierarchical host-guest supramolecular self-assemblies.This protocol is broadly applicable to most samples of hierarchical host-guest supramolecular self-assembly system in the case of well-soluble samples. You may obtain beautiful research results from UV-vis spectra, TEM, SEM, and these tests can be operated in a relatively low concentration (∼10a) of host-guest supramolecular system. Low bonding constant leads to weak binding capability resulting in irregular morphology of assembly. The cucurbit[7]uril (CB[7]) is also used in Chen et al.,Another limitation is binding constant All sample solutions of titration should be prepared again for UV-vis spectra test instead of only replacing the invalid sample.1H-NMR section).The NMR peaks of sample are too weak to split clearly, while the concentration of sample cannot be increased because of the limit of solubility. .It is hard to distinguish the shifts of NMR peaks of guest molecules after adding host molecules For both SEM and TEM tests, the unidentified pieces may come from: (1) unavoidable impurities from water and silicon wafer; (2) overhigh concentration or excess volume of sample solution dropped on the wafer. Thus, the steps in SEM or TEM parts should be carried out carefully to avoid artificial interference. Specially for SEM test, silicon wafer should be washed more than three times with ethanol or acetone carefully and dried under a constant temperature , but there is no need of wash step for TEM grid. It is hard to confirm morphology features of each hierarchical self-assembly state in SEM or TEM test. (Step 21 in SEM section and Step 28 in TEM section)Do the tests as much as you can. Because the non-covalent property of supramolecular self-assembly, the incomplete self-assemblies may happen in some samples occasionally. Find a morphology that appears most frequently which highly meets the expected assembling mechanism . Moreovequanli3273@gmail.com ).Further information and requests for resources and reagents should be directed to and will be fulfilled by the lead contact, Quan Li (This study did not generate new unique materials.


This paper reports on a combined experimental and numerical modeling investigation of cracking of concrete slabs with GFRP reinforcement. At this stage of the project, attention is given to early-age cracking driven by plastic shrinkage, preceding longer term considerations of cracking resistance over the service life of field applications. Of interest is the effectiveness of GFRP reinforcement in restricting plastic shrinkage cracking. Nine small-scale slab specimens were subjected to controlled evaporation rates. Images of crack development were acquired periodically, from which crack width estimations were made. Comparisons were made between slabs reinforced with conventional steel and those reinforced with GFRP, along with control specimens lacking reinforcement. During the period of plastic shrinkage, the time of crack initiation and subsequent crack openings do not appear to be influenced by the presence of the reinforcing bars. To understand this behavior, six early-age bond tests were conducted for both types of the bars after 1, 2, and 3 h exposure to the controlled evaporation rate. In addition, concrete strength development and time of settings were measured using penetration resistance tests on a representative mortar. The numerical modeling component of this research is based on a Voronoi cell lattice model; in this approach, the relative humidity, temperature, and displacement fields are discretized in three-dimensions, allowing for a comprehensive investigation of material behavior within the controlled environment. Based on the measured bond properties, our simulations confirm that the reinforcing bars restrict crack development, though they do not prevent it entirely. Corrosion of the reinforcing steel is a primary factor affecting the durability of structural concrete, especially during exposure to severe environments. The potential for corrosion-induced durability problems can be reduced by controlling crack formation in the concrete, particularly at early ages when the concrete is susceptible to cracking. Alternatively, non-corroding materials can be used as concrete reinforcement.Plastic cracking is one of the earliest faults in concrete elements and, if not addressed, can reduce the durability and service life of the structure. Cracks act as pathways for detrimental chemicals and other species that can foster corrosion of embedded steel reinforcement ,2. Many The present research involves the use of glass fiber-reinforced polymer (GFRP) bars to reinforce concrete exposed to severe conditions such as those presented by marine environments. GFRP rebars are employed to avoid the risk of corrosion in concrete structures exposed to harsh marine environments or de-icing salts. The durability of internal reinforcement is critical to the service life of these structures . DevelopDespite the fact that FRP bars have been successfully used for structural reinforcement in concrete members in building and bridge projects for the past 30 years, there has only recently been interest in using FRP bars and meshes as secondary reinforcement in place of conventional temperature and shrinkage steel reinforcement for non-structural concrete members such as plain concrete footings, concrete slabs-on-ground, and plain concrete walls . Of inteHerein, the performance of GFRP bars relative to that of conventional steel reinforcement is investigated through a combination of physical experimentation and numerical modeling. The bases for the experiments and modeling exercises are first described, after which the results are presented. In laboratory tests, the type of reinforcement does not significantly influence the time of cracking and crack opening driven by plastic shrinkage. The modeling exercises indicate a dependence of crack opening on the type of reinforcement, and otherwise produce similar results.Various concrete mixture designs were evaluated to increase the probability of inducing plastic shrinkage cracking. The concrete was designed according to the provisions of the ACI 211.1-91 . This cooperties . Both coThree different types of slabs were considered. Along with plain concrete slabs that served as control specimens, the slabs were reinforced with either conventional steel or GFRP bars, both having a 9.5 mm (0.375 in) nominal diameter. The steel bars used in this study were conventional steel reinforcement bars with a modulus of elasticity of 200 GPa (29.0 Msi). The physical and mechanical characteristics of the GFRP bars are presented in Potential for plastic shrinkage cracking was assessed using a modified form of the setup described in ASTM C1579-21 . The setThe main challenge in this testing approach is to consistently ensure the occurrence of cracking in the early stages. Therefore, an environmental chamber was designed and built to provide the critical rate of evaporation for plastic shrinkage cracking. The environmental conditions were controlled for the first 6 h. On the average, for the entire set of slab specimens, the following conditions were maintained: a wind velocity of 7.8 m/s, a relative humidity of 37%, and an ambient temperature of 32.2 The early-age bond behavior between the reinforcement and concrete was evaluated using ASTM D7913-14 . Controlnificant . The samThe ASTM C403-16  StandardAlong with the time of crack onset, A control specimen of plain concrete was cast and allowed to cure for 18 h in a laboratory environment. This specimen did not show any signs of cracking see d, which In  305R-20 . This ob 305R-20 .t = 2 h (the approximate time of crack onset) is only about 0.14 MPa. For comparison, the ASTM D7957-22 [To understand the ineffectiveness of the reinforcement in controlling plastic shrinkage cracking, as observed in plastic shrinkage testing, early-age bond tests were conducted to evaluate the bond strength of reinforcement with fresh concrete. It was found that the bond strength at D7957-22  requiresVoronoi cell–lattice models (VCLM) are used to simulate the early-age thermal and hygral fields acting in the concrete as well as the mechanical response to those actions. Such discrete modeling approaches are particularly effective in simulating cracking and other forms of displacement discontinuity ,34 whileCementitious materials hydration is based on the model proposed by Riding et al. . The degaterials .v is wind speed over the concrete surface. The heat of hydration is calculated at the lattice nodes and used as a source term in the thermal analyses.The temperature field within the model domain is simulated using a lattice composed of conduit elements. A convective boundary layer models the heat transfer between the exposed surface of the specimen and the environment. The convective heat exchange  follows :(3)ΛT=5The humidity field is simulated using a parallel set of conduit elements based on the same set of nodal points and element connectivities. After the concrete sets, moisture transport is assumed to be governed by a diffusion process . A convective boundary layer accounts for moisture transfer between the drying surface of the concrete and the environment. The modeling of this layer is analogous to that of the temperature field expressed by Equation , althougThe solution process involves a time-stepping scheme in which the temperature and humidity fields are solved for each time step using the Crank–Nicholson method in conjunction with a fixed-point algorithm to achieve convergence.The simulated thermal and hygral fields produce thermal and hygral strains, respectively, within the mechanical component of the analysis framework, which is based on the rigid body–spring concept . These sConcrete property development, including strength and stiffness, depends on the degree of cementitious materials hydration. In particular, solidification theory is used to simulate creep processes and stiffness development ,54. The  modeled .At a given stage of strength development, concrete fracture is simulated using an energy-conserving crack band model ,57. The Each reinforcing bar is represented by series of frame elements, which connect to the concrete nodes via special link elements . The linA VCLM discretization of the test specimens and plywood formwork is shown in The above model was modified to approximate behavior of concrete in the plastic state. In particular, the modeling of plastic shrinkage was based on the simulations of Ghourchian et al. , as presHerein, the volumetric strain is introduced into the lattice model from the time of horizontal strain commencement, while the preceding accumulation of vertical strain is neglected. This volumetric strain continues until the end of the plastic stage, after which drying shrinkage is assumed to be caused by moisture diffusion, as described above. The rate and duration of this form of volumetric strain are model parameters. The stress-based fracture criterion, as expressed by Equation , is retaV is wind velocity (km/h), r is the relative humidity of the environment. The evaporation rate is modified to account for maturation of the concrete according tot is the maturation time (h) and a is a time constant set to 3.75 h for concrete [The model was further extended to include the effects of evaporation on concrete temperature. Heat flux due to evaporative cooling is determined byqe=−Echlconcrete .As a first step, the degrees of hydration at the initial and final setting points as determined through the aforementioned penetration tests were further calibrated. For this purpose, the 150 mm × 150 mm × 150 mm samples were modeled using the VCLM while accounting for the environmental boundary conditions. The coarse aggregate fraction of the mixture composition  was remonce data , the degt pastes . The degFor the simulations of temperature development in the slab specimens, the coefficient of convective heat transfer (Equation ) was mulTo simulate the cracking behavior of the slab specimens, the preceding thermal analyses were coupled with hygral and mechanical analysis modules . The cont = 6 h were much smaller than those observed in the experiments. Furthermore, significant distributed microcracking occurred over the drying surface, and the resulting macrocrack  propagated from the upper surface downward. In contrast, by introducing plastic shrinkage as a volumetric strain, the central device acts as a stress (or strain) riser such that cracking initiates at the device tip and propagates upward. Ghourchian et al. [Prior to simulating plastic shrinkage in terms of volumetric strain, as shown in n et al.  observedThe range of simulations covered one representative case for each reinforcement configuration, including simulations of P-SC-1, S-SC-1, and G-SC-1. For concrete in the fresh state, finite amounts of stiffness and strength are needed to operate the mechanical model and represent the cohesive behavior of the concrete mixture. In the absence of such data, the initial stiffness and tensile strength were set at t = 130 min at the tip of the central restraining device. The crack propagates upward and becomes visible on the drying surface at t = 170 min. The time of travel of the crack from the device tip to the concrete surface is in general agreement with radiographic image-based observations [For the case of P-SC-1, which served as a control specimen without reinforcement, cracking in the model is initiated at rvations . Rapid crvations .t = 6 h) as that observed in the experimental program. Beyond the time of concrete setting, drying shrinkage contributes to additional crack opening. From about t = 8 h onward, cooling of the concrete causes contraction and additional crack opening. Over this short time span, however, the contributions of drying shrinkage and thermal contraction to crack opening are relatively small.Crack opening profiles are presented in For all of the slab simulations, the initial driver of crack formation and development  was introduced as a prescribed function of time independent of concrete maturity and the environmental boundary conditions. Furthermore, the influences of plastic settlement were not included in this modeling effort. Lack of cracking observed along the reinforcing bar suggests that plastic settlement is not a primary factor in initiating cracking, though further investigation is needed. In Pan et al. , the VCLt = 2 h, the approximate time of plastic shrinkage crack initiation. More specifically, bonding between the reinforcement and concrete was modeled using piecewise linear fittings of the t = 2 h test results presented in As noted in t = 6 h for specimens S-SC-1 and G-SC-1, which contained steel bar and GFRP bar reinforcement, respectively. For comparison, the opening profile for specimen P-SC-1 is presented along with the average crack opening measured for all specimens within the experimental program. The presence of bar reinforcement does not prevent crack formation, though the simulated crack openings are locally restricted to the bar position. Considering the low bond strength for the GFRP bar at t = 2 h, its ability to restrict crack opening might be surprising. However, the concrete material is relatively compliant over the same time period, such that even small bond strength enables significant load transfer between the reinforcement and concrete. Short distributed fibers, which supply a much larger bonded surface area, are a common means of avoiding this form of plastic shrinkage cracking.In this research, physical testing and numerical modeling have been used to study the performance of GFRP bars in restraining early-age cracking in concrete slabs. The period of interest begins with the concrete in a fresh state and extends up to several hours after setting. For comparison, concrete slabs reinforced with steel bars were examined, as well as control specimens without reinforcement. Several conclusions can be made.Consistent cracking behavior of the control specimens was obtained by optimizing the concrete mixture design, controlling the environmental boundary conditions, and raising the initial temperature of the concrete, which increased the evaporation rate from the drying surface. The initial temperature was raised by heating the mixing water before its addition to the dry materials. Cracking initiated with the concrete in a plastic state prior to setting.For the test specimens considered herein, crack opening does not appear to be restricted in the vicinity of a bar; rather, openings are fairly uniform over the specimen width. In other words, the presence of reinforcing bars of either type, i.e., GFRP or steel, does not have an appreciable effect on time of plastic shrinkage crack initiation and ensuing crack opening.t = 2 h was only 0.14 MPa and 2.08 MPa for GFRP and steel bars, respectively). Such low bond strength might be responsible for the ineffectiveness of the reinforcement in restraining plastic shrinkage cracking.Bond strength between both types of reinforcement and the early-age concrete was measured and found to be small (e.g., the maximum bond strength at It was observed that the plastic shrinkage cracking can occur for evaporation rates that are even below the commonly accepted critical value of 1.0 kg/mThe proposed numerical analyses elucidate the roles of the various thermo-hygro-mechanical processes that affect early-age cracking of the specimens. In particular, by modeling plastic shrinkage as a bulk material phenomenon in the form of volumetric strain, the central device acts as a stress riser. The simulated cracking initiates from the device tip and propagates upward, as seen in other studies using images based on X-Ray radiography.Concrete temperatures, and as such the properties of the concrete, are influenced by the thermal properties of the formwork and related boundary conditions. The modeling of evaporative cooling was found to be essential in simulating the concrete temperatures, particularly early on in the testing period, where measured temperature tended to decrease with time.Our numerical analyses support the notion that discrete bar reinforcement does not prevent the formation of plastic shrinkage cracks. In contrast to the experimental observations, however, the presence of the bar reinforcement does restrict crack opening. Higher bond strength leads to smaller crack openings local to the bar. The differences between the measured and simulated opening profiles are grounds for further study.Although the modeling exercises provide insight into the use of GFRP bars to reduce plastic shrinkage cracking, a number of simplifying assumptions have been made. In particular, volumetric strain due to plastic settlement/shrinkage was introduced as a prescribed function of time, patterned after experimental observations in previous studies. The use of a strength-based fracture model required additional assumptions the regarding baseline values of strength and stiffness representing the cohesive behavior of the fresh concrete. Further development of the model with respect to these points is needed.For practical situations in which plastic shrinkage cracking is a concern, the results presented herein indicate that routinely-spaced GFRP bar reinforcement is not effective in preventing crack formation and development. Due to their larger specific surface area, well-distributed short fibers are a proven means of addressing the problem of plastic shrinkage cracking.


The internal temperature of the mass concrete is not constant. In the actual project, the internal temperature of the concrete will experience a process of rapid warming to reach the peak temperature and then slow down. In this study, volume measurement method is used to simulate the internal volume deformation of mass concrete under actual engineering conditions. The embedded strain gauge was embedded in concrete with a water–cement ratio of 0.32 for 28 days, and the development of total volume deformation and autogenous volume deformation of concrete under variable temperature conditions was studied by external heating of concrete. The results show that the finer the cement, the earlier the concrete starts to shrink, and the greater the total shrinkage of the concrete. The high temperature will promote the hydration of cement with different fineness and will reduce the total porosity of their paste, but the proportion of harmful pores in the paste with finer cement particles is lower. With the rapid development of the economy and technology, mass concrete is more and more widely used in modernizing industrial societies because of its outstanding structural strength and durability. In the world, many high-rise buildings, railways, highways, bridges, urban road, subways, dam power stations, airports, shopping malls, and other infrastructure projects that require mass concrete have emerged ,2,3.There are currently no uniform quantitative regulations for mass concrete in scientific institutions around the world. American Concrete Institute (ACI) regulations: regardless of the concrete poured in any site, due to the size of the concrete volume being too large, the heat of hydration generated by the concrete must be strictly controlled to reduce the volume of deformation problems due to heat of hydration to minimize the concrete cracking situation, which is called mass concrete. The Ministry of Housing and Urban-Rural Development of China stipulates that two rules can classify mass concrete. One is bulk concrete with a minimum geometry of concrete structural entities of not less than 1 m. The second is expected to produce harmful cracks due to temperature changes and shrinkage caused by the hydration of the cementitious materials in the concrete. The Japanese Institute of Architects (JIA) defines mass concrete as concrete whose structural length in the section is longer than 800 mm and where the exothermic hydration of the cement results in a temperature difference between the inside and outside of the concrete of more than 25 °C. Although there is no quantitative uniformity in academia regarding mass concrete, there is some common understanding of the characteristics of mass concrete. For example, the total volume of concrete poured is large, the internal heat of hydration does not easily escape, leading to increased internal temperatures, the total shrinkage is considerable, and early cracks are likely to occur.Cracks in concrete have different causes when concrete is at different ages. At later ages, external forces are exerted on the concrete structure in excess of what it can carry, while concrete cracks at earlier ages mainly because of problems with the concrete itself. The early cracking of concrete is because mass concrete will use a low water–cement ratio to ensure its workability. A low water–cement ratio will allow for more cement to participate in the hydration reaction, causing more significant total shrinkage and ultimately causing concrete cracking ,5,6,7,8.Thus, both the cement’s hydration reaction and the concrete’s temperature affect the concrete’s volume shrinkage deformation. Volume shrinkage can be filled by increasing the concrete before the initial setting. As hydration continues and a strength structure is formed in the concrete, volume shrinkage will be inhibited, and stresses will be generated. The tensile stresses generated internally will then increase with the increase in modulus of elasticity. When the tensile stresses exceed the tensile strength of the concrete, penetration cracks will be generated within the concrete ,18,19,20We have learned that the early age cracking of mass concrete is the main reason for the volume shrinkage of the concrete, which is caused mainly by the autogenous shrinkage of the concrete. As with the definition of mass concrete, the current academic definition of autogenous shrinkage is also relatively vague. Lynam  was prob3S, C3A, C2S, C4AF, and their hydration reaction equations are [However, the current view of Sun , who disions are .2C3S + Due to the compound’s density difference before and after the hydration reaction, the chemical shrinkage is expressed macroscopically as a reduction in absolute volume after participation in the hydration reaction. Powers quantified the chemical shrinkage of different cement clinker phases, which was 6–7 mL/(100 g) for 100% complete hydration of silicate cement and up to 20 mL/(100 g) for the incorporation of silica fume . The totHowever, the above definition of concrete autogenous shrinkage still has some limitations. Because the temperature generated inside the concrete does not conduct quickly in large volumes, there is a process of temperature change inside the concrete that rises rapidly and then falls slowly, and both autogenous shrinkage and thermal expansion are significantly correlated with temperature change ,34,35,36In this experiment, four different fineness grades of cement were cast into concrete specimens and placed in a variable temperature curing chamber, which was externally heated to simulate the temperature change from rapid warming to slow cooling of the concrete inside the mass concrete. The influence of cement fineness on volume deformation of mass concrete under actual project conditions was obtained. These data can provide reference for construction and subsequent maintenance of actual engineering.In this study, the compressive strength and autogenous shrinkage of concrete with different fineness were tested under the condition of variable temperature. The pore size and hydration degree were associated with the results of the above two tests through the paste microstructure and MIP results. The detailed flow chart is shown in 30, C40, C50, and C60. The specific surface areas were measured by using Burr’s specific surface area tester  as 300, 327, 373, and 377 m2/kg, and the fineness of the four types of cement was measured by using a negative pressure sieve analyzer as 12.21 μm, 7.62 μm, 4.18 μm, and 3.44 μm, respectively. The manufacturer is yarn screening factory . The fineness of the four types of cement was 12.21 μm, 7.62 μm, 4.18 μm, and 3.44 μm, and the four cement numbers were C30, C40, C50, and C60. The experimental S95 mineral powder and secondary fly ash were sourced from Nanjing Pudi . The experimental high-performance polycarboxylic acid water reducing agent was sourced from Nanjing Sobute . The chemical composition of cement, mineral powder, and fly ash is shown in The experimental P-grade silicate cement was homemade, using Jiyuan clinker  and gypsum from Nanjing Zhonglian . The four types of cement produced by ball milling for 30, 40, 50, and 60 min, respectively, are CThe water–cement ratio directly determines whether or not self-desiccation shrinkage will occur, with H.E. Davis stating that for concrete with a water–cement ratio of 0.6–0.94, the size of self-desiccation shrinkage is between 1/5 and 1/10 of the total long-term shrinkage of these concretes . Tazawa’The temperature rise profile inside the concrete is simulated for actual situations, and the concrete specimens are maintained in a variable temperature curing chamber. The heating rate of the curing chamber is controlled in real time by the internal temperature of the specimen fed back from the strain gauge to match the temperature profile of the specimen as closely as possible to the actual project. The temperature data curve in the actual project is shown in Compressive strength is one of the essential properties of concrete, and the value of early compressive strength is used to evaluate the degree of hydration of cement particles in concrete. The test method followed the Standard for Mechanical Test Methods of General Concrete GB/T50081-2002, using cubic compressive strength as the strength characteristic value of concrete. The concrete was sealed with PVC film as soon as it was poured into the mold to ensure it was in a simulated moisture-proof condition. We put the concrete into the curing box to simulate the internal temperature change of the concrete for 24 h and then demoulded it. After demoulding, we continued to put it into the curing box at variable temperatures. The concrete compressive strength tester (a) and the compressive strength specimen (b) are shown in 30, C40, C50, and C60 in batches, and then pour the concrete into the shrinkage test device, with the device numbers C30, C40, C50, and C60 in sequence. The concrete was poured to a height of 400 mm. During that time the strain gage was placed in the middle of the concrete to ensure that the gage takes uniform stress data, and 20 mm of liquid paraffin was poured into the upper part of the concrete after the concrete had set to insulate the upper part. This was covered with the same sealing lid as the bottom and the mold was used for measuring the autogenous shrinkage into the variable temperature maintenance box. The initial setting time of concrete was used as the starting point for measuring the autogenous shrinkage strain. The data collection device (a) and curing box (b) are shown in The testing device for concrete autogenous shrinkage was composed of a PVC hollow pipe with a height of 500 mm and a radius of 160 mm with a VWS-15 vibrating string strainer made by Ge Nan Industrial Company  and a GDA16 full-function data acquisition instrument. The effective length of the specimen poured into the tube is 400 mm. A sealing cap with an inner diameter of 160 mm is coated with special PVC glue to seal the hollow tube’s end as the mold’s bottom. Mix four kinds of cement numbered CMercury piezometer is one of the main instruments for measuring the pore structure of cement paste. Before pore structure testing, samples were dried under a vacuum at 105 °C for 4 to 5 h to remove capillary water and alcohol from the specimens. Under certain pressure, the mercury was pressed into the open hole in the cement paste. The stress and the volume of mercury pushed into the hole were continuously recorded during the test, ranging from 300 μm to 7 nm. The orifice diameter corresponding to each pressure can be calculated from Washburn’s  equationP—the pressure required to press the mercury into the hole;d—the pore diameter of the hole the mercury is pressed into;γ—the surface energy of the cement;θ—contact angle of mercury with the wall of the hole.The strength of the cement paste and the pore structure are closely related. PoreMaster GT-60 automatic mercury compression meter was used to test the pore structure of four types of net cement pastes, the equipment is made by Quantachrome company . Cement paste pore size (d) is divided into four classes: less than 20 nm for harmless pores; 20~50 nm for less harmful pores; 50~200 nm for harmful pores; more than 200 nm for more harmful pores. The actual control of hardened cement slurry strength, permeability, and volume changes is the pore size distribution rather than the porosity. The water–cement ratio and the degree of hydration mainly govern the pore gradation. Pores larger than 50 nm mainly harm the strength and permeability of the cement paste; pores smaller than 50 nm primarily affect the drying shrinkage and creep of the cement paste.The effects of silicate cement with different fineness on the compressive strength of silicate concrete are shown in As can be seen from 30, C40, C50, and C60 is 68.5%, 73.47%, 81.17%, and 78.21%, respectively. At 3 days, the compressive strength of C60, the finest particle, reached 57.4 MPa, compared with 56.5 MPa for C50, 51.8 MPa for C40, and 48.7 MPa for C30. At 60 days, the compressive strengths reached 69.9 MPa, 66.3 MPa, 59 MPa, and 57.1 MPa, respectively. The compressive strength is negatively correlated with the fineness of cement particles, and the different concrete strength values at intermediate ages follow the above rule. The compressive strength of concrete under a variable temperature curing environment is shown in 60 is 85.29% of the 60-day compressive strength of concrete, the 3-day compressive strength of concrete for C50 is 87.80% of the 60-day compressive strength of concrete, the 3-day compressive strength of concrete for C40 is 85.22% of the 60-day compressive strength of concrete, and the 3-day compressive strength of concrete for C30 is 82.12% of the 60-day compressive strength of concrete. The finer the particle size of the cement, the higher the proportion of the 3-day compressive strength to the 60-day strength. As the age increases, the value of strength increases per unit of time decreases. The average compressive strength increase from 3 to 7 days was 2.75 MPa, with an average increase of 0.69 MPa per day. The average compressive strength increase from 7 to 28 days was 4.225 MPa, with an average increase of 0.22 MPa per day. The average compressive strength increase from 28 to 60 days was 3.1 MPa, with an average increase of 0.097 MPa per day.The 3-day compressive strength of concrete for CThere are two possible reasons for the above results. On the one hand, the finer the particles of silicate cement, the higher the hydration activity, and the easier it is to hydrate quickly in the early stage, generating more hydration products dense the structure of the concrete, and the strength grows fast . With thThe effect of different fineness of silicate cement on the total volume deformation of silicate concrete is shown in εt—the total volume deformation of silicate concrete;−6/F;k—the measurement sensitivity of the strain gauge in 10t—the measured value of the strain gauge strain at moment t in F;F0—the reference value of the strain gauge for concrete deformation in F;Ft—the measured value of the temperature of the strain gauge at the moment t, in °C;T0—the temperature reference value of the concrete deformation in °C;F−6/°C for this experiment.b—the coefficient of thermal expansion of the strain gauge, provided by the manufacturer, 13 × 1030, C40, C50, and C60, corresponding to −92 με, −193 με, −273 με, and −274 με at 14 days, respectively, the line 0 in After the peak temperature, as the temperature decreases, the degree of influence of temperature on the total strain gradually decreases, and the effect of the contraction of the cement itself on the overall volume deformation gradually increases. The total strain data for the four concrete became negative at 200 h, 133 h, 93 h, and 89 h, respectively. Eventually, the different cement fineness caused different times of starting shrinkage and total shrinkage of the concrete. The total shrinkage strain for different fineness of cement under variable temperature conditions was from small to large for CThe effect of different fineness of silicate cement on the total volume deformation of silicate concrete is shown in t—the autogenous shrinkage deformation of silicate concrete;ε−6/F;k—measurement sensitivity of the strain gauge in 10t—the measured value of the strain gauge at the moment t, in F;F0—the reference value of the strain gauge for concrete deformation in F;Ft—the measured value of the temperature of the strain gauge at the moment t, in °C;T0—the temperature reference value of the concrete deformation in °C;F−6/°C for this experiment;b—the coefficient of thermal expansion of the strain gauge, provided by the manufacturer, 13 × 10−6/°C.α—the coefficient of thermal expansion of silicate concrete, the concrete is mainly composed of basalt and natural sand, α is taken as 7 × 1060 microstrain was −80 με. The microstrains of concrete in groups C30, C40, and C50 are 72 με, −19 με, and −74 με, respectively, the line 0 in 60 by 152 με, 61 με, and 6 με, respectively. It can be seen from 60 and C50 with the finest particles are close. This trend is maintained during the age period of 7 days–28 days. This indicates that there are other factors besides the fineness of the cement that affect the size of the autogenous shrinkage of the concrete after 7 days of age. After 14 days, the autogenous shrinking microstrain of the concrete in the three groups was unchanged, and the hydration reaction was finished.The greater the fineness of the silicate cement at 28 days of age, the earlier the concrete starts to self-shrink. Because the finer the particles in the early stage, the more contact area between cement and water, the faster hydration reaction rate can be obtained, and the greater the number of hydration products C-S-H gel generated per unit of time. At 7 days, the finest-grained group of concrete CThe pore structure of cement slurries with different fineness was determined by mercury intrusion porosimetry (MIP). The results of the tests are shown in However, the smaller the value of cement fineness, the more significant the proportion of total pores occupied by harmless pores. The compressive strength of concrete of this fineness is positively correlated with the proportion of harmless pores to total pores. The larger the proportion of harmless pores, the smaller the proportion of multi-harmful pores. The higher the corresponding compressive strength of the concrete at the same age. This is because in the early hydration process, the finer the cement, the smaller and denser the hydration products can be generated per unit of time. These hydration products can fill the cavities inside the concrete faster, enhance the denseness of the concrete, reduce the overall size of the holes, and effectively reduce the percentage of multi-harmful holes. The skeleton and filler work together to improve the compressive strength of the concrete.30, C40, C50, and C60 in a, b, c, and d of The study characterized the internal structure of cement paste with different fineness using SEM analysis. The SEM images of cement paste numbered CThe comparison of SEM images showed that as the fineness of cement particles gradually increased, the more completely the cement particles hydrated, the more flocculent hydration products were formed, and the overall texture became dense. In addition, the internal structure of the cement paste was improved in terms of pore size, microcrack formation, and filling. On the other hand, it can be observed in Autogenous shrinkage in cement paste is determined by chemical shrinkage, self-desiccation shrinkage with pores, and cracks after hardening. From (1)Under variable temperature conditions, the finer the cement particles, the faster the compressive strength of concrete grows. When the test age increases, the less the compressive strength of concrete increases per unit of time.(2)The finer the cement particles are, the greater the total volume deformation and self-shrinkage of the concrete, and the earlier the shrinkage begins during the 28-day temperature change course.(3)Throughout the variable temperature phase, temperature is not the only dominant factor affecting the total volume deformation of concrete. In 1–7 days, the self-shrinkage produced by cement hydration becomes the main factor affecting the total volume, so the study of the total volume deformation of concrete under variable temperature conditions should be divided into three stages.(4)The high-temperature environment at an early age promotes the hydration reaction of cement and reduces the difference of porosity of net cement paste with different fineness, but the smaller the fineness of cement, the greater the proportion of harmless pores in cement paste and the smaller the proportion of multi-harmful pores. The compressive strength of concrete at the same age is mild with this phenomenon.The most significant conclusions of this study are summarized as follows: