Investigation on mechanical parameters of concrete having sustainable materials

Abstract

Conventional concrete utilizes cement, sand (fine aggregate), coarse aggregate (CA) and water. To achieve sustainability cement, sand and CA can be replaced with different waste materials. The objective of research includes the development of mixture design of sustainable concrete and assessing fresh state concrete properties and hardened concrete properties of developed sustainable concrete. Generally, CA covers 65% to 75% of the concrete. The source of CA is limited on earth, so an alternative of CA is required. At the same time, there is an ample amount of construction and demolition (C&D) waste-producing in India annually. Dumping and utilization of the C&D waste is another challenge. Sustainable concrete contains waste materials such as GGBS, fly ash (FA) and other SCMs in substitution of cement, recycled coarse aggregate (RCA) in place of CA, and manufactured sand (m-sand) in place of fine aggregate. Different SCM materials such as FA, GGBS, Silica Fume and Lime as a replacement of cement and RCA as replacement of CA along with m-sand as a replacement of fine aggregate were incorporated in concrete in this research, and thus the mechanical performance of the concrete was determined. In present study, different concrete mixes of M25 grade are produced using cement, lime, fly ash, silica fume and GGBS along with 100 % m-sand, 50% RCA, and 50% CA. cement is replaced with different SCMs in different percentages. Workability using slump test, density, and compressive strength at 7 days and 28 days of developed concrete mix were determined. It was observed that workability of developed concrete was reducing by replacing cement with sustainable materials and aggregate with RCA and m-sand. The results indicate that the compressive strength of the developed concrete mix reduces with replacement of sustainable materials. Sustainable mix having 15% cement, 50% GGBS, 15% lime, 15% FA and 5% SF gives maximum compressive strength among other mixtures. In this study almost 95% of cement is replaced by different combination of SCMs, 50% CA are replaced by RCA and 100% fine aggregate is replaced by m-sand.