Sustainable Utilization of Recycled Aggregates from Demolition Waste for Non-Load Bearing Hollow Blocks

Sustainable design and construction have become essential in recent decades. The use of construction materials, particularly aggregates from recycled construction and demolition waste, has contributed to addressing challenges such as the scarcity of natural resources, the high cost of landfilling, and the increased demand for aggregates. This paper examines the production of non-load bearing hollow blocks using Recycled Concrete Aggregates (RCA) and Recycled Masonry Aggregates (RMA) derived from demolition waste following the Beirut Port blast. Five different mixtures were prepared by varying the replacement rates of Natural Aggregates (NA) with recycled aggregates (RCA or RMA): Mix 0 (reference mix with NA only), Mix 1 (30% RCA), Mix 2 (60% RCA), Mix 3 (10% RMA), and Mix 4 (20% RMA). Mechanical tests were conducted along with thermal testing using a customized Simple Hot Box with the Heat Flow Meter method. The results showed that Mix 2 (60% RCA) and Mix 3 (10% RMA) achieved the required compressive strength, while Mix 1 (30% RCA) and Mix 4 (20% RMA) required an additional 10% cement to meet the strength requirements. The thermal properties of hollow blocks containing varying proportions of RCA and RMA demonstrated improved thermal resistance.