ABSTRACT
Most of the applications of high strength concrete have been used in high raised buildings, long span bridges and in some special structures. However, more stringent quality control, use of better quality materials and proper care in the proportioning of concrete and choosing better admixtures are important factors to be considered while designing a concrete mix.
In the present investigation, the study has been carried out for two high grades of concrete viz.
M50 and M60 with replacement of cement by fly ash from 0% to 50% by adding superplactisizer
(CONPLAST — SP 430 of FOSROC chemicals). For the two grades of concrete 108 cubes,
18 prisms and 36 cylinders have been cast. The strength characteristics such as Compressive
strength for 7 days, 28 days and 56 days curing period, flexural strength, spilt tensile strength
and modulus of elasticity of concrete for 56 days curing period were tested and compared the
results of high strength high volume fly ash concrete with conventional concrete. Based on test
results, the use of high volume fly ash concrete resulted in lower compressive and flexural
strengths at early ages (before 28 days) and higher mechanical properties after 28 days up to
replacement of fly ash was 30% as compared with conventional concrete and thus encouraging
the results.
Keywords: High strength concrete, Admixtures, Replacement, Fly ash, Strength characteristics, Conventional concrete, Mechanical properties.
