Design and Assessment of a Lightweight Polymer Concrete Utility Manhole

Abstract

Polymer concrete is a composite using polymer instead of portland cement as a binder. It allows optimizing the tensile and cracking strength and the chemical resistance of a concrete structure. In this study, different formulations were assessed in order to optimize a polymer concrete underground utility manhole with minimum weight. Formulations were based on an epoxy-amine system mixed with fine regular-weight aggregates and ultralightweight aggregates. The objective was to design and assess an underground utility structure with the epoxy chemical resistance, strength, and lightweight and to study whether the replacement of regular-weight aggregates by ultralightweight aggregates would contribute to improve the strength and reduce the structure weight. Two polymer concrete systems were designed from its formulation, and their mechanical performance was evaluated experimentally. A numerical model was developed for a polymer concrete underground utility structure made from the different formulations. It was simplified as a box subjected to typical soil loads. The size of the box is a standard one. Its minimum wall thickness is specified for sustaining the in-use service pressures obtained from numerical simulation. The model predicted that the epoxy/regular-weight aggregate formulation could be used with a wall thickness significantly smaller than the formulation with ultralightweight aggregates. In addition, the underground utility structure made with this formulation would weigh six times less than the same box made with a traditional portland cement concrete.