EFFECT OF CLASS-C FLY ASH ON COMPRESSIVE STRENGTH OF RAC MADE WITH RECYCLED AGGREGATES FROM DIFFERENT STRUCTURAL MEMBERS

Abstract

In this research study laboratory investigation to check the effect of fly ash in recycled aggregate concrete made with recycled aggregates from different structural members is presented. Conventional aggregates are replaced with recycled aggregates from demolished waste in the dosage of 35%. Demolished waste was used from five structural members. In each group of recycled aggregates, class C-Fly ash was used from 0 to 15% in the increment of 2.5%. In each batch 15 cylinders of standard size were used. For preparation of all specimens 1:2:4 mix with 0.5 water cement ratio was used. Out of 540 cylinders equal number was cured for 7-, 28-, and 90-days. From the compressive strength test results, it was observed that addition of fly ash improves the strength characteristics of recycled aggregate concrete but up to 10%. Among recycled aggregates from different structural members, recycled aggregates from column concrete performs better than others. 28-day cured samples showed better results than 7-, and 90-day cured samples with maximum increase in strength equal to 17.07%. Effect of mixed aggregates on compressive strength revealed better performance of elongated curing.