Strength and hygric properties of ETICS applied at various temperature, using adhesives with different cellulose ethers

Abstract

The ETICS comprises a prefabricated insulation product bonded to the wall or a combination of adhesive and mechanical fixings. The insulation is faced with a rendering consisted of one or more layers (site applied), one of which contains a reinforcement. Adhesives used for bonding the insulation to the wall and base coat include cellulose ethers. These chemical compounds are used in building materials as thickeners, binders, film formers, and water-retention agents. Cellulose ethers influence on the physico-mechanical characteristics of a mortar. Temperature application and then conditioning of adhesives strongly affect the water retention. This paper presents a study on the impact of different temperatures on the setting and hardening adhesives with three types of cellulose ethers (HEC, HPMC and HEMC). The tests included water retention in freshly – mixed mortars and bond strength between the adhesive and substrate in mortars. Water transport in freshly-mixed mortars containing cellulose ethers were examined with classical and new methods Time Domain Reflectometry. During the laying and curing time the ambient temperature was hold on to 5±2 °C (reduced), 23±2°C (standard), 30±2°C(increased) in the relative humidity 50±5% or 80±5%. Adhesives were cured for 4 weeks. The pull-off test was performed on the following samples: without supplementary conditioning (dry condition) and after immersion of the adhesive in water for 2 days and 2 h drying at laboratory conditions. The tests were performed on the substrates: a smooth concrete slabs and the expand polystyrene insulation boards. The hygric properties were measured in the sample thickness 12 mm and 9 mm during the first 24 hours.