Use of recycled concrete and rice husk ash for concrete: A review

Abstract

The rapid development of populations and the demand for concrete consumption are generating the need to produce greater quantities of cement, which has negative effects on the environment. Approximately 0.87 kg of CO2 are produced per cement production; in addition, the use of aggregates is generating great concern in the construction industry, due to the cost and restriction of aggregates. Similarly, the accumulation of recycled concrete aggregate (RCA) and rice husk ash (RHA) contributes to pollution. Therefore, the objective of this manuscript is to review the literature of recent years on the use of RCA and RHA and the effect it generates on the various properties of concrete. For this purpose, indexed articles were used, between the years 2017-2021, with a total of 80 indexed articles evaluated. The literary analysis shows the most outstanding results including these materials that, when 8% RHA is added, the concrete reaches a compressive strength of up to 70 MPa; as well as the flexural strength by adding a combination 50% RCA + 1.50% basalt microfibers where it increases up to 29.44%. On the other hand, when 15% RHA is added, a compressive strength of 48.8 MPa is achieved; in turn, the flexural strength with 10% seashell for the fine aggregate and 20% RHA for the cement, reaches a strength of up to 65 MPa. In conclusion, the behavior of concrete undoubtedly depends on the proportions of RCA or RHA; however, the percentages should not exceed 8% and 15%, respectively.