Recycled Aggregates from Construction and Demolition Waste in the Manufacture of Urban Pavements

Abstract

Construction and Demolition Waste (CDW) is among the largest waste streams in the world. Therefore, within the Circular Economy concept, there is a growing interest in its reuse. The purpose of this work was to study the use of recycled aggregates (RAs) obtained by a specific separation method from CDW, replacing natural aggregates (NAs) in the manufacture of precast concrete elements, such as kerbstones and paver blocks. The physical and technological properties of precast products formulated with RAs were analysed in accordance with current regulations, comparing them with those of commercial products manufactured with NAs. The results indicated that partial or total substitution of NAs by RAs increased the water absorption and apparent porosity values of the precast elements while reducing the bulk density and compressive strength. However, all units manufactured with RAs showed breaking load values higher than the minimum required by EN 1338 and, in some cases, slightly higher average tensile strength values than the reference material. In addition, some of the compositions including RAs gave rise to pieces that, according to their flexural strength, were classified as class 1 and marked S in accordance with EN 1340. According to abrasion resistance, in most cases, the precast elements are classified as Class 4 and I (≤20 mm). Finally, precast concrete produced from RAs satisfies the tolerance requirements for classification as class 3 (≤1.5 kg m−2). Therefore, it could be suitable for use in high pedestrian or traffic areas.

Assessing the Feasibility, Usability, and Durability of Recycled Construction and Demolition Waste in Road Construction in Morocco

“…This result confirms what was observed in the literature review [34,36,65]. Generally, recycled CDWs almost have higher water absorption values than natural aggregates that have water absorption (WA) values between 0.5% and 1.5% [35,66,67]. However, these higher WA values of the recycled CDWs aggregates could be attributed to their lower density and therefore higher porosity compared to natural aggregates [64].…”

“…However, these values are acceptable and are in accordance with the requirements of the EN 13242 standard [48]. It was reported that the recycled aggregates has a significantly higher LA and MDE coefficients than the natural ones [66,67]. This can be probably due to the presence of old cement paste surrounding natural aggregates and ceramic materials, etc.…”

Recycled Fine Aggregates from Mortar Debris and Red Clay Brick to Fabricate Masonry Mortars: Mechanical Analysis

“…In recent years, the sustainable engineering of construction development has increased; therefore, several researchers have doubled their efforts toward projects where the mean objective is to analyze the feasibility of recycling construction and demolition waste (CDW) as new building materials, focusing on mechanical behavior, durability, and environmental impact [ 1 , 2 , 3 , 4 , 5 , 6 ]. One way these residues can be used is as partial substitutes for natural aggregates (NAs) in concrete and mortar mixes, such as recycled coarse aggregates (RCAs) and recycled fine aggregates (RFAs) [ 7 ].…”

Influence of recycled aggregate on the compressive strength and absorption percentage of Lima 2020 pedestrian pavers

“…[4] One of the strategic lines of the European Union policies aims to ensure the "Circular Economy" through the efficient use of raw materials and residues and the generation of clean energy. For that, policies on waste management must be directed in respect of the hierarchy of 4Rs established by the normative: reduction, reuse, recycle, and recovery [5].…”