Recycling Waste Latex Paint in Concrete with Added Value

Abstract

With increasingly more stringent environmental regulations and the development of municipal waste collection programs, waste latex paint (WLP) has developed into the largest liquid waste material (by volume) being collected in North America. Thus, its disposal has become a major concern for environmental and economical reasons. At the same time, the concrete industry is gradually shifting toward green materials and practices with special focus on sustainable development. Because latex can improve some key properties of concrete, it may be possible to recycle WLP in concrete manufacturing with added value. In this study, fresh, mechanical, and durability properties of concrete incorporating various proportions of WLP were investigated. Moreover, leaching tests on aged concrete specimens incorporating WLP were carried out, along with a full-scale field test for constructing a stamped WLP concrete deck and sidewalk. The initial setting time of concrete was not reduced due to WLP addition, whereas the final setting was slightly reduced, which is perceived as an advantage. Concrete incorporating WLP was less vulnerable to the curing regime than conventional concrete. Compressive strength decreased with WLP addition, but adequate strength results for structural applications could be obtained with up to 20% WLP partial replacement for mixing water. The flexural strength of concrete increased with the addition of WLP. The durability of concrete was also significantly enhanced due to WLP addition, and no significant emission of toxic substances was detected in leaching tests of WLP concrete specimens subjected to 300 freezing-and-thawing cycles. A full-scale test for the construction of a stamped concrete deck and sidewalk indicated additional field applicability advantages for WLP concrete.