Protecting the environment and natural resources using green Roller Compacted Concrete (RCC) containing fine and coarse recycled copper slag aggregates

Abstract

As the environmental policies and protection guidelines of natural resources are among the great challenges in the concrete production/construction industry, they can be properly addressed if effort is made to produce green, nature-friendly concretes by different waste materials. To this end, the current study has replaced natural fine and coarse aggregates of the roller compacted concrete (RCC) with 0 %, 10 %, 20 %, 30 %, 40 %, 50 % and 60 % copper slag (CS) aggregates, which are largely-produced waste materials. Numerous tests were done to evaluate the mechanical properties and durability of different-age CS concretes and determine their environmental and economic benefits. According to the results, the compressive strength of the 91-day specimens increased up to 40%, and their tensile and flexural strengths increased up to 60 % compared to the control specimen. Scanning electron microscope (SEM) images revealed that using low CS volumes strengthened the concrete microstructure and filled the voids. In CS concretes, the surface water absorption was less than 7 %, and at 60 % CS, the capillary water absorption, water penetration depth, and ultrasonic wave penetration reduced by, respectively, 47.32 %, 2.76 %, and 12.22 % compared to the CS-free concrete. In general, the green CS-RCC involves many environmental benefits and reduces the production costs by about 7.70–46.18 %.