Properties of fiber incorporated concrete blocks manufactured using recycled aggregates

Abstract

The construction and demolition industry generates a significant quantity of concrete waste, presenting an environmental challenge. The concrete waste generated can be processed to produce Recycled Aggregates (RA) of various sizes. Utilization of Recycled Aggregates (RA) as a substitute to conventional aggregates in concrete has captured considerable attention in the past few years, owing to its promising environmental and economic advantages. However, the combined utilization of recycled fine and coarse aggregate in the production of concrete for low-strength application has not been adequately explored. In this article, an attempt is made to investigate the characteristics of concrete blocks made with RA and polypropylene fiber (PF) are investigated for different cement content. Cement and PF content varied from 8 to 12% and 0% to 2% respectively in production of concrete blocks using Recycled Fine Aggregates (RFA) and Recycled Coarse Aggregates (RCA) at different replacement intervals. Water absorption of blocks manufactured across all replacement intervals of RA was less than 10%. Blocks containing 75% RFA and 25% RCA resulted in improved compressive strength of the order more than 3.8 MPa. Rate of improvement in compressive strength of block was 11% to 20% and 6.5% to 8.2% when the fiber dosage was increased from 0.5% to 1% and 1% to 2% respectively. The optimal fiber dosage was found to be 1%, beyond which no notable improvement in mechanical properties of blocks was observed. Use of RA in concrete blocks reduced embodied energy by 19% to 24% for varying cement content from 8 – 12%. Cost of blocks was found to be reduced by 10 – 15% when made with PF dosage of 0 to 2% with 8% cement content.