PERFORMANCE CHARACTERISTICS OF HIGH-VOLUME GRADE-I FLY ASH CONCRETE

Abstract

The challenges involved in the near future for the civil engineering community will be to meet the huge demand for infrastructure in a sustainable manner. Concrete is the most widely used construction material worldwide. However, the production of Portland cement releases large amounts of green house gases. increasing global warming of the planet. Again the disposal and dumping of fly ash as a waste material may cause severe environmental problems/hazards. High-volume fly ash ,concrete which consumes high amount of fly is the holistic solution to meet those problems in sustainable manner. The aim of this present work is to study the variation of compressive strength, split tensile strength, flexural strength, modulus of elasticity of three mixes where Portland cement were replaced by 40%, 45%, 50% of grade-I fly ash with respect to control mix (0% fly ash) and to judge the suitability of the use of high volume fly ash concrete in Indian environment. Four concrete mixes were made, a control mix without fly ash and other concrete mixes were made by replacing cement with 40%, 45% and 50% of grade-I fly ash by mass. More than 180 specimens were cast. Water-to-cernentitious material ratio was kept same to investigate the effects of replacing cement with high volumes of grade-I fly ash. The tests conducted were Compressive strength, Split tensile strength,. Flexural strength, Modulus of elasticity at the age of 7 days,28 days, 90 days on the concretes. Results shows that the replacement of cement with 40%, 45%, 50% of fly ash content reduces the compressive strength, split tensile strength, flexural strength at the age of 7 days, 28 days with respect to control mix (0% fly ash). Cement replaced by 40% was giving compressive strength 28.09 MPa at 28 days. So it is concluded that sufficient strength of plain concrete (i.e. without fly ash) can be produced with less cement content. It is also observed that there is continuous increase of compressive strength, split tensile strength and flexural strength of SM2, SM3 and SM4 with age.