Title:
Mechanical Properties of Concrete Made with Chemically-Produced Recycled Concrete Aggregate (RCA)
Author(s):
Paul Horst Seiler
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/23/2022
Abstract:
According to the NRMCA returned concrete represents 2% - 10% of production and producers indicate that this number is growing. This represents an operational, financial, and environmental problem for concrete producers—and one that is not easily solved. Currently producers address this problem by fabricating concrete blocks, crushing hardened concrete, or land filling returned concrete. Being able to take returned concrete still on its plastic state, and transform it into a revenue stream without adversely affecting the environment by quickly transforming it into a usable raw material that can be sold independently and/or incorporated into future concrete production is a preferable solution The process to treat returned concrete is very simple. The steps are: 1) estimate the volume of the returned concrete, 2) add the returned concrete admixture treatment, 3) mix for about two minutes, 4) discharge the granulated material on the ground in piles that are about 12 inches (300 mm) in height, 5) flatten the piles sometime during the day of discharge, and 6) turn the flattened piles the next day and move the recycled concrete aggregates (RCA)h to the desired storage location to be sold and/or used in concrete production. This paper will discuss the process of fabricating the aggregates, optimal mix design proportioning to obtain good mechanical and durability properties as well as a brief economic analysis utilizing tools being developed by the NRMCA – National Ready Mix Concrete Association. (1) John Luciano is a Senior Scientist at Master Builders Solutions with over 40 years of experience in concrete and admixtures. (2) Steve Schaef is a Group Manager for the Engineering group at Master Builders Solutions with over 15 years of experience in concrete and admixtures (3) Paul H Seiler is the Technology Director at Master Builders Solutions with over 20 years of experience in concrete and admixtures.