Influence of two ceramic substrates on water absorption and modulus of elasticity of rendering mortars

Influência de dois substratos cerâmicos na absorção de água e no módulo de elasticidade de argamassas de revestimento

Abstract

The characteristics of masonry substrates affect rendering mortar performance. This study compares three mortar types (dry-mix, ready-mix, and mortar produced in the laboratory) applied to two types of ceramic blocks differing in Initial Rate of Absorption (IRA) and cast in metal/PVC molds. Mortars were characterized in the fresh and hardened states, and their IRA and dynamic modulus of elasticity were determined after application onto the blocks. While the ready-mix mortar had the highest variation on IRA results depending on the substrate, for the mortar produced in the laboratory, using structural or non-structural blocks did not make a difference. Mortar and substrate types influenced the modulus of elasticity, with values rising from the ready-mix mortar to the dry-mix and that produced in the laboratory. Mortars on ceramic blocks had higher modulus than those in metal molds. Further studies are recommended on porosity, non-absorbent substrates, lateral waterproofing, and potential wave transmission through the substrate.

Keywords
Rendering mortar; Ceramic block; Substrate influence; Initial rate of absorption; Dynamic modulus of elasticity