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.
Concrete mix proportioning as per IS 10262:2009 - Comparison with IS 10262:1982 and ACI 211.1-91
The Bureau of Indian Standards (BIS) has released the final code on concrete mix proportioning in December 2009. Before this, the draft code was circulated among practitioners. Significant changes have been made in the new code adapting from international codes on concrete mix design. The new code can now be used for designing a variety of concrete mixes using both mineral and chemical admixtures. With this code RMC having high degree of workability facilitating pumping can also be designed. In this paper an effort has been made to examine the major differences between BIS and the American Concrete Institute (ACI) methods of concrete mix design. Using both these methods, step-by-step procedure for calculating the ingredients is given. The difference between the old BIS (IS 10262:1982) and new BIS (IS 10262:2009) is also highlighted.
The properties of cementitious materials superplasticized with two superplasticizers based on aminosulfonate–phenol–formaldehyde
Abstract Two kinds of aminosulfonate–phenol–formaldehyde condensate superplasticizers AS based on sodium p -aminobenzenesulfonate and SDMAS based on sodium p - N , N -dimethylaminobenzenesulfonate were synthesized. The properties of cementitious materials superplasticized with the synthesized superplasticizers such as the hydration heat and viscosity of cement pastes, compressive strength and flexural strength of cement mortars was assessed. The results showed that the SDMAS has the stronger ability of inhibiting cement hydration than AS, the initial viscosity of paste with AS is lower than that with SDMAS, the mechanical strength of superplasticized mortars are higher than those of plain mortars at 7 and 28 days, and the mechanical strength of mortars with SDMAS are higher than with AS at 28 days and lower than with AS at 7 days.