Suitability Investigation of Recycled Concrete Aggregates for Concrete Production: An Experimental Case Study

Abstract

In developing countries, construction and demolition waste (CDW) is disposed to landfill, causing social, environmental, and economic crises. In these nations, CDW exponentially increase due to their rapid economic growth, industrialization, and urbanization. This paper aims to examine the possibility of recycling concrete waste for production of new concrete in Ethiopia. Physical and mechanical characteristics of recycled concrete aggregate (RCA) acquired from concrete waste are thoroughly examined. Though the RCA exhibited relatively lesser performance compared with the natural coarse aggregate (NCA), it reveals the same properties as of normal-weight aggregates in several instances. The performance of concrete specimens which employ RCA up to 20% is evaluated from workability, strength, and permeability aspects. The utilization of RCA slightly affects the workability and the water permeability properties of the concretes. Replacement of 10% of the NCA by the RCA enhances the compressive strength of the hardened concrete by 8%. The difference between the splitting tensile strength of the concretes which employ RCA and conventional aggregates is trivial. Generally, this work demonstrates the practicability of concrete waste recycling to produce new concrete or construction materials in Ethiopian context.

Comparative Investigation of the Effect of Recycled Fine Aggregate from New and Old Construction Wastes in C-25 Concrete in Ethiopia

“…The cleaning procedure enhanced the recycled aggregate quality, and this improved the properties of the concrete with recycled aggregate at fresh and hardened states. The fine particles attached on the surface of the recycled concrete aggregate increased the water absorption capacity of recycled fine aggregate and also had a lower density than natural aggregate [4,5,9]. Thus, the compressive strength was less than the conventional concrete due to the high water absorption capacity of the recycled fine aggregate.…”

“…Ethiopia is one of the developing countries in which the concept of recycling construction and demolition waste has not yet been implemented [4]. In Ethiopia, the solid waste management proclamation No.…”

“…This indicates that Ethiopia is behind on the recycling of construction and demolition wastes. However, for the last seven years, some research [4,11] was undertaken on the recycling of construction and demolition wastes. Woubishet [4] assessed the suitability of recycled aggregate in concrete and the effect of recycled concrete aggregate on concrete properties.…”

“…The waste generated from the construction industry in developing countries is enormous due to poor management practices. Additionally, the rate of construction is high due to quick urbanization, industrialization, and economic development [4]. The major problem in the construction industry is the disposal of construction wastes.…”

“…These wastes are found collectively in a site with different sizes and different amounts and are disposed to the disposal site as landfill. The recycling of concrete structures as concrete aggregate in Ethiopia was investigated, and promising results were found [4]. The physical properties of recycled concrete aggregate are within the range of normal weight aggregate.…”