THE STRUCTURAL PERFORMANCE OF CONCRETE CONTAININGCRUSHED ROCK DUST AND FLY ASH WITH THE ADDITION OFCOIR FIBREAmit Kumar and Pushpendra Kumar Sharma
The present research work has been carried out by using crushed rock dust and fly ash as cement replacementin combined proportion of 20% CRD and 0% fly ash mix together with the gradual increase of 2.5% fly ashand simultaneously gradual decrease of 2.5 % of CRD with the addition of 0.5% coir fibre by weight ofcement. Last proportion taken was 10% CRD and 10% fly ash. Use of this material in concrete not onlyimproves the strength of concrete but also leads to the proper disposal of these materials, reducing theimpact of these materials on environment. In this research the compressive and flexural strength of concretewith replacement of ordinary Portland cement by crushed rock dust (CRD) and fly ash with the additionof 0.5% coirfiber are studied. Eleven concrete mixes are prepared and compared with the nominal mix(with 0% CRD, fly ash and fiber). Test results for compressive and flexural strength show higher gain instrength for mixes using CRD, fly ash and fiber as compare to nominal mix. It was observed that cementreplace with 12.5% CRD and 7.5% fly ash with 0.5% coir fiber gave the highest strength value. Propertyworkability also studied for different concrete mixes. The addition of coir fiber gives slight more variationin the workability as compare to concrete made by using CRD and fly ash. The fiber into fresh concrete canincrease the ductility of the concrete and also acts as a crack arrester.