A sustainable and developing building industry requires large quantities of raw materials such as aggregates and crushed rocks. However, sourcing natural aggregates is becoming more problematic due to environmental impacts. Hence, the use of secondary materials, such as recycled aggregate can reduce the amount of natural aggregates required. Lightweight concrete is frequently used by the building industry, and it is commonly produced with natural lightweight aggregates such as scoria, which results in high production costs. Preliminary tests on recycled aggregates showed that recycled masonry has a similar specific gravity as scoria and relatively good strength. Hence, crushed masonry can be used to replace natural lightweight aggregates. This paper discusses the use of partial or total replacement of normal-weight aggregates with recycled lightweight aggregates, and its effects on the strength and elastic properties of concrete. It is shown that concrete mixes with recycled aggregates generate comparable results to mixes with scoria, but at lower production costs.
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