Effect of polymer and conventional molds on the aesthetical surface quality of concretes

Abstract

Abstract This paper investigates the surface quality of concrete specimens made with molds of different polymers and conventional concrete mold. Five kinds of polymers of various polarity, wettability, surface roughness and thickness were chosen and conventional molds (wooden plate with epoxy coating) were used with and without release agent. Specimens were prepared by pouring concrete into the molds and demolded after one day. The surface roughness, porosity and reflection ability of the specimens were tested with surface roughness tester or observed on 1d, 7d and 28d. Results show smoother molds can produce smoother specimens no matter the polarity, wettability and thickness of the polymers. However, mold made from a blend of polymers can produce very rough specimen although the mold itself is smooth. Molds of low friction and mixed polymers will increase surface porosity and deteriorate reflection ability. Implications of these results on improving concrete surface quality by choosing suitable polymers and techniques are discussed.