Mechanical properties of concrete produced with recycled coarse aggregates – Influence of the use of superplasticizers

• Influence of the aggregates’ crushing process on the concrete’s (RAC) performance.
• Influence on concrete mechanical properties of coarse aggregates from concrete waste.
• Influence of two types of superplasticizer (average and high water-reducing capacity).
• Relative efficiency of superplasticizers in RAC compared with conventional concrete.

Waste management has become vitally important since the demand for natural resources and the amount of construction and demolition waste have greatly increased, putting huge pressure on the environment. The main goal of this study is to evaluate the effects of the introduction of superplasticizers on some mechanical properties of concrete with recycled concrete aggregates and compare them with the corresponding properties of conventional concrete made with natural aggregates. The experimental program is described and the results of workability, specific density, compressive strength, splitting tensile strength and abrasion resistance tests carried out on concrete are presented. Two different crushing processes and their effects on aggregate properties were tested. By varying the replacement percentage of natural by recycled aggregates, with or without the addition of superplasticizers, it was possible to identify some weaknesses and strengths of the recycled aggregates concrete which can contribute to developing the more widespread use of this material.