Preparation and Properties of Silicon-Modified Epoxy Grouting Material for Repairing Microcracks

Abstract

To improve the performance of epoxy grouting materials and achieve better repair of microcracks in cast-in-place concrete bridge deck pavements, polydimethylsiloxane (PDMS) and diluent were used to modify epoxy resin. The mechanical properties of silicon-modified epoxy grouting materials produced using different preparation processes were analyzed, and the best preparation process was optimized. The working performance of silicon-modified epoxy grouting material was determined, and the environmental adaptability before and after composite modification was explored. The results showed that the suitable reaction temperature, time, and PDMS content are 100°C, 3 min, and 8%, respectively. The higher the temperature, the better was the groutability and the shorter was the curing time. Therefore, the construction temperature should be at least 35°C. The impact resistance and strength of the grouting materials were improved significantly after the addition of PDMS. In addition, the strength essentially was formed after 5 days. This indicates that the curing age is 5 days. Silicon-based modified epoxy grouting materials have good environmental adaptability. After thermal shock, 30-day temperature variation treatment, and 30 freeze–thaw cycles, the flexibility and bonding properties of the materials were excellent, and were much higher than those of the unmodified materials. Although the tensile strength was slightly lower than that of the unmodified materials, it still remained at about 60 MPa.