An Experimental Study of Effects of Superplasticizer on Fresh and Hardened Properties of Concrete
This paper presents the results of an experimental research on the workability and compressive strength of ordinary and standard concrete. Superplasticizers are commonly known as High Range Water Reducers (HRWRs) because it permits low water cement ratio as well as the workability also affected. In this paper the properties of concrete mixtures with three different dosages of superplasticizers SNF have been investigated. In this experimental programme superplasticizer Sikament®170(SWP) of basically modified naphthalene/melamine formaldehyde sulphonate dispersion and having brown liquid confirming to IS: 91031999 & IS: 2645, ASTM C 494/C494M, Type F has been used. The properties investigated are workability on the fresh state and compressive strength on the hardened state of concrete by using three mixes with three superplasticizer dosages (0.2%, 0.4% and 0.6%) is used. Various concrete mixes (M-20, M-30 and M-40) are design by IS 10262:2009, Concrete Mix Proportioning Guidelines. Compressive strength at 7 and 28 days was also determined. The graphs between different percentage of superplasticizers with W/C ratio and compressive strength are plotted. Overall 72 specimens (concrete cube) with the dimension of 150 mm x 150 mm x 150 mm were fabricated at laboratory.
Experimental Investigation on Strength Characteristics of Self- Compacting Concrete Using Superplasticizer
This paper deals with the results of an experimental research on Self-Compacting Concrete (SCC) with superplasticizer. Superplasticizers are commonly known as High Range Water Reducers because it permits low water cement ratio as well as the workability also affected. In this study, the local materials and Sika Viscocrete-10 are used and their properties are determined. All tests are performed according to ASTM standard. The mix proportions and testing methods for flow characteristics of self-compacting concrete are different from conventional vibrated concrete. Various trial mixes with different superplasticizer of 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4% and 1.5% are conducted to satisfy the workable properties of SCC. The fresh properties of SCC such as slump flow test, slump flow T500mm test, V-funnel test, Vfunnel T5minutes test and L-box test are carried out and checked according to ACI 237R-07 guideline. Harden properties of compressive strength of SCC is determined at the age of 3 days, 7 days and 28 days. Mix design is calculated for the target strength M34.2 (4959psi). The results of the present investigation indicate that the performance and compressive strength of SCC with admixture 0.8% was observed to be much better than other four successful mixes. KeywordsCompressive Strength, Self-Compacting Concrete (SCC), Superplasticizer, Workability
High strength self-compacting concrete Original solutions associating organic and inorganic admixtures
Abstract Self-compacting concrete (SCC) is today a pretty well-known technology. It has been established by several authors, on the basis of numerous engineering achievements, that the main benefit that can be expected from this kind of material is the high speed of casting. Furthermore, the concrete’s transportation and placing down are greatly facilitated by the use of pumps; the extreme fluidity allows the realization of complex pieces and enables the access to difficult casting zones, which leads to an improvement of the structure’s durability. However, the concrete’s formulation remains difficult and sensitive; still too often, in their first approach, some formulators simply increase the water-to-cement ratio or only adjust the dosage of superplasticizer, which generates some poor-quality concrete. In this paper, we present a new method based on the use of two admixtures : a nanometric, amorphous, silica SiO2 (for its reactivity with the cement paste), combined with a specific polysaccharide (for its suspending ability), both of them used under a liquid form. We show that one can formulate, at a reasonable cost, a highly fluid concrete, without bleeding or segregation. The setting kinetic is improved, which allows the reduction of the demoulding time; the surface of the hardened concrete is smooth and homogeneous; and the final strengths values achieved are in line with those attained with high strength concrete.