Investigation some properties of recycled lightweight concrete blocks as a fine aggregate in mortar under elevated temperature

Abstract

The main objective of this study is to assess the effect of utilizing waste material (lightweight concrete blocks) as partial replacing of fine aggregate. To do so, seven mix designs were utilized to prepare 168 mortar specimens (84 cubes and 84 prism) with the replacement ratios of 10% and 20% waste material fine aggregate instead of traditional sand at different temperatures of 24 ᵒC, 200 ᵒC, 400 ᵒC, and 600 ᵒC. The combination of two type waste material together in one mixture (waste lightweight concrete blocks with waste clay bricks or waste lightweight concrete blocks with waste glass) was tested with and without fiber (1% polypropylene fiber by volume). The physico-mechanical properties of mortar specimens involving flow rate, fresh density, weight loss, compressive strength, flexural strength and water absorption were determined. The hardened tests were implemented at age of 28 days. The results demonstrated fresh density experienced a decrease when utilizing recycled materials especially waste lightweight concrete block at 20%. Compressive strength showed improving with replacing normal sand by waste materials and that enhancing was clear at high temperatures. The specimens that utilized waste lightweight concrete block with waste glass aggregate illustrated clearly reduction in water absorption comparing with control mix at different temperatures.