Effect of recycled gypsum board as partial fine aggregate replacement on compressive strength and water absorption of mortar

Abstract

This paper presents the effects of partial fine aggregate replacement by recycled gypsum board on density, compressive strength, and water absorption of mortar with cement paste and fine aggregate to mortar volumetric ratio of 50% and water to cement ratio of 0.40, 0.45, 0.50, 0.55 and 0.60 by weight. The results showed that density of mortar reduced with the increase of recycled gypsum board due to its light weight. Mortar with W/C of 0.60 possessed the highest density according to sufficient water to obtain perfect compaction which was conformed to water absorption results that these mortars possessed the lowest water absorption, comparing to others. The lowest water absorptions were in the range of 2.3-6.7%. Compressive strength of mortar reduced approximately 30-50% by replacing recycled gypsum board of 0.2 by mortar volume. Failure type of mortar with the replacement of recycled gypsum board of 0.2 or higher was ductile material with large deformation at failure point. The suitable mortar mixtures for building bricks type A with respect to TIS standard 77-2545 shall be consisted of recycled gypsum board replacement of 0.1 by mortar volume with W/C of 0.45 or 0.60, so the compressive strengths were 24.6 MPa and 25.5 MPa with water absorption of 14.1% and 3.2%, respectively.