A Review Paper on the Strength Characteristics of the Concrete Mix with Flyash

The utilisation of flyash in various non-structural applications is appreciable. There is an advantage of high calcium content in flyash that it behaves more cementitious than pozzolanic compared to class F ash. At the same time, as there are certainly variations in the properties of NLC flyash, variational composition of the chemical compounds should be found out, thorough research studies is essential for establishing the utilisation of high volume of high calcium flyash in structural concrete. The present work is aimed on the bulk utilisation of class C flyash for structural concrete applications. Conventional concrete grade of M30 is designed by Indian method of mix design and based on the seventh day strength of trial mixes; an optimum trial mix proportion is arrived and validated for its workability characteristics and twenty eighth day compressive strength. Partial replacement of cement with class C flyash is aimed upto 90%. Concrete mixes having 50%, 60%, 70%, 80% and 90% cement replacement by weight of flyash are considered. Including the reference concrete without flyash and in parallel, with and without plasticizers totally, twelve types of concrete mixes are tried initially for experimental study. As the compressive strength results of 70%, 80% and 90% cement replacement with flyash are not encouraging, only the 50% and 60% cement replacement levels with flyash are considered for further study. In addition flyash replacement by silica fume is also planned by 10% and 20% respectively for both the replacement levels and without and with plasticizers. Therefore from the adequately decided total mix of twenty, only fourteen different concretes are considered for further thorough studies.