ADHESION BETWEEN FRESH POLYMETHYL METHACRYLATE MORTAR AND FRESH CEMENT MORTAR OR CONCRETE

摘要

In this paper, the adhesion between fresh polymethyl methacrylate (PMMA) mortar and fresh cement mortar or concrete is examined considering the production of precast cement concrete products with thin polymer mortar surface layers. To prepare the specimens for adhesion test, fresh PMMA mortar is placed with thicknesses of 0, 5, 10 and 15 mm in molds 50Xl00X200mm, and then fresh cement mortar or concrete is placed on the fresh PMMA mortar at time intervals of 0, 5, 10, 15, 20 and 30 min after fresh PMMA mortar placing. The specimens are subjected to different curing conditions, i.e., steam cure and water cure. After curing, the specimens are tested for adhesion in tension. The effects of thickness of fresh PMMA mortar, time interval after fresh PMMA mortar placing and curing conditions on the adhesion in tension between the fresh PMMA mortar and fresh cement mortar or concrete are examined. From the test results, the placing of the fresh cement mortar or concrete at a suitable time interval on the PMMA mortar with an appropriate thickness produces a good adhesion between the fresh PMMA mortar and fresh cement mortar or concrete in water cure, showing almost cohesive failure in the cement mortar or concrete substrates. A significant improvement in the adhesion in tension of the fresh PMMA mortar to the fresh cement mortar or concrete is achieved in water cure at time intervals of 10 to 15 min after fresh PMMA mortar placing with thicknesses of 10 to 15 mm. As a result, the production of precast cement concrete products with PMMA mortar surface layers is found to be possible.