Effects of pre-wetting aggregate on the properties of mortars made with recycled concrete and lightweight aggregates

Lidiane Fernanda Jochem,Marilda Barra Bizinotto,Diego Aponte,Janaíde Cavalcante Rocha

doi:10.1590/s1517-707620190002.0677

Lidiane Fernanda Jochem, Marilda Barra Bizinotto + Show 2 more

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https://doi.org/10.1590/s1517-707620190002.0677

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Abstract

ABSTRACT This paper examines the suitability of partially replacing natural aggregate, sand, (NA) with recycled concrete aggregate (RCA) or lightweight aggregate (LWA) in mortars, under the hypothesis that pre-wetting aggregates would produce improvement in mortar properties. Fresh mortar properties such as density, entrained air content, consistency and heat of hydration, as well as hardened mortar properties such as dry density, compressive and flexural strength, and dimensional instability at 0% and 100% saturation were determined. The results show that mortars made with natural aggregate (75%) and recycled concrete aggregate (25%) have similar properties to mortars made with only natural aggregate (100%) and that pre-wetting the aggregates does not influence the properties of mortars significantly. Therefore, partial replacement with recycled concrete aggregate is a viable alternative for producing mortar.

Highlights

Sustainability issues such as the environment, solid waste disposal areas, and natural resource depletion are major concerns, pointing to a growing need for further research
This paper examines the suitability of partially replacing natural aggregate, sand, (NA) with recycled concrete aggregate (RCA) or lightweight aggregate (LWA) in mortars, under the hypothesis that pre-wetting aggregates would produce improvement in mortar properties
The results show that mortars made with natural aggregate (75%) and recycled concrete aggregate (25%) have similar properties to mortars made with only natural aggregate (100%) and that pre-wetting the aggregates does not influence the properties of mortars significantly

Summary

Introduction

Sustainability issues such as the environment, solid waste disposal areas, and natural resource depletion are major concerns, pointing to a growing need for further research. The use of fine recycled aggregate is of great interest since, according to ANGULO et al [1], recycling plants generate a large amount of fine aggregate (less than 4.8 mm), representing nearly 50% of the weight of the crushed recycled aggregate used. It was believed that fine fractions of recycled aggregate had low quality properties, so they were discarded [2]. Recent studies have shown that the properties of fine recycled concrete aggregate do not differ significantly from those of coarse fractions and that the use of the former can bring benefits to the final material and the environment [3,4,5,6,7,8]

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