Effect of powdered mixed recycled aggregates on bedding mortar properties

Abstract

This study analyses the physical–mechanical effect in cement-based bedding mortar containing fine recycled construction–demolition waste (CDW) aggregate. For this, the ultra-fine fraction of a natural sand (<.125 mm) was replaced with fine recycled CDW aggregate and two types of mortars were manufactured: a low-strength mortar made with a volume ratio cement-to-aggregate of 1:7 and a high-strength mortar made with a volume ratio cement-to-aggregate of 1:4. A CEM II/BL 32.5N cement was used in both types of mortars. In the mixtures, .1 cm³ of a plasticiser was incorporated and the amount of water was experimentally adjusted to achieve a consistency of 175 ± 10 mm. The incorporation of ground recycled aggregate improved most physical–mechanical properties of the mortars tested, except for workability and shrinkage which were only slightly jeopardised. In the long term the compressive strengths increased significantly in both types of mortars.

Keywords:

• mortar
• waste treatment
• recycled aggregate
• filler
•  construction and demolition waste