Analysis and modeling of uniaxial compressive creep of MMA-modified unsaturated polyester polymer concrete

Abstract

Creep and shrinkage are the major time-dependent phenomena occurring in concrete. Because they significantly affect the long-term dimensional changes and relaxation of restrained stresses in concrete, it is of great importance to accurately consider these characteristics in the structural analysis and design process. In this study, laboratory experiments were conducted to examine the creep under uniaxial compression and linear setting shrinkage of unsaturated polyester (UP) polymer concrete modified with three different levels of methyl methacrylic (MMA) monomer (i.e., 10, 20, and 30 wt.%). The creep of UP-MMA polymer concrete was measured as per ASTM C512 under a sustained compressive stress of 20% of the compressive strength for 90 days, while the linear setting shrinkage was monitored based on the JSCE method for 7 days. Results indicated that as the MMA content increased, the 90-day creep increased although the differences were non-significant. On the contrary, the linear setting shrinkage tended to decrease with an increase in MMA content. The compressive strength was found to decrease by 7.2% as the MMA content increased from 10 wt.% to 30 wt.%. Additionally, the present study compared the measured creep coefficients with those estimated by ACI 209 and CEB-FIP Model Code 1990. It was revealed that the current creep models for Portland cement concrete are inappropriate in predicting the creep of UP-MMA concrete. A new predictive model for creep applicable to the UP-MMA concrete is proposed.