Effect of Crushed Concrete on Some Properties of Modified Reactive Powder Concrete Reinforced with Micro Steel Fibers

Abstract

The disposal of concrete debris is in high demand due to the rising amount generated by demolition activities and the breaking up of concrete goods during transportation and production. Moreover, it is imperative to preserve natural resources. In recent times, there has been a growing inclination to utilize these waste materials as a partial replacement for aggregate. This paper presents the results of a study that examined the utilization of crushed concrete as aggregates. The crushed concrete was sourced from inspected cube samples of a road project in Baghdad and subsequently reduced in size till they reached a maximum dimension of 10 mm. The original reactive powder concrete was used to make crushed concrete (25% and 100% by volume of the concrete), micro-steel fibers (1% by volume of the concrete), and fine sand (no more than 1% by volume of the concrete). Study of the properties of reactive and regular powder concrete, including their compressive and flexural strengths, as well as their density. When 25% crushed concrete was added to modified reactive powder concrete, its compressive strength increased by 16.86% and its flexural strength increased by 10.57%. After seven days and twenty-eight days of testing, respectively, these enhancements were noted. A 12.04% decrease in compressive strength at seven days and an 18.2% decrease at 28 days occurred when sand was replaced with 100% broken concrete in the mixture. In a similar vein, flexural strength dropped by 23.5% after seven days and 20.6% after twenty-eight days.