Optimization of the formulation of micro-polymer concretes

This research investigates the optimization of micro-polymer concretes (MPC) formulations in order to produce a construction material that has excellent physical and mechanical properties, such as minimum void content, high Young's modulus and excellent strength properties. An epoxy resin reinforced with a graded mixture of coarse and fine sands is used as a binder to design the micro-polymer concretes. Effects of curing time and binder contents were evaluated through ultrasonic wave propagation method and flexural, compressive, direct and tensile tests, performed at room temperature. The porosity of different MPC formulations as well as the distribution of the voids size is investigated as a function of curing time using mercury intrusion porosimeter (MIP). Results show that with increasing the binder content, the total pore volume and the maximum pore size are reduced significantly. The kinetics and the mechanisms of diffusion of water in MPC depend strongly on the mass fraction of resin. All the mechanical properties of MPC stabilize after 3 days curing at ambient temperatures. The micro-polymer concrete designed with a polymer content of 9% shows the highest physical and mechanical characteristics such as strengths, rigidity, the lower voids content and thus the best durability. The experimental results reveal that the mechanical behavior of MPC is time dependent. Scanning Electronic Microscopy (SEM) was applied to observe the microstructure and the porosity and to understand the failure mechanism of MPC. (C) 2010 Elsevier Ltd. All rights reserved.