Effects of recycled paperboard mill wastes on the properties of non-load-bearing concrete

Abstract

Population growth and increasing demand for industrial enterprises such as pulp and paper production lead to environmental problems such as over-exploitation of resources and pollution of soil, air and water. Thus, for the importance of reducing the negative effects of incineration and landfilling of wastes for the protection of environment, two kinds of recycled paperboard mill wastes were used as partial replacement of sand (volume percentage), to produce non-load-bearing lightweight concrete. Waste type 1 consists of paperboard chips mixed with small amount of sand, and waste type 2 consists of paperboard chips mixed with expanded polystyrene and nylon. This study was carried out in laboratory scale to achieve acceptable strength and minimum density by using maximum amount of waste, in accordance with ASTM-C129 for non-load-bearing lightweight concrete construction. Therefore, three types of concrete, including concrete containing waste type 1 (replacing 0, 60, 70 and 80 % of waste and sand), concrete containing waste type 2 (replacing 0, 55, 75 and 95 % of waste and sand) and concrete containing both waste types, were constructed. Different tests on the fresh and hardened concrete, including slump, pH, oven-dry density, compressive and tensile strengths, flexural strength, flexural toughness and water absorption, were carried out. The results indicate that the use of waste type 1 is more reliable than waste type 2 in terms of concrete specifications and standard-conforming viewpoints. Results revealed that use of these wastes in concrete can save the paperboard industry disposal costs and produce ‘greener concrete’ for construction.