Properties of Low-Exothermic polymer grouting materials and its application on highway

Abstract

Frost heaving and thawing settlement are the main problems in highways in permafrost regions. Non-aqueous reacting polymer is a relatively effective and environmentally friendly material to repair highways. However, its expansion and heat release influence on different strata in perma-frost areas remains unclear. Thus, a low-exothermic polymer was used to conduct grouting tests in different strata of frozen soil. The heat release characteristics and thermal conductivity of low exothermic polymers during the reaction were studied by laboratory experiments. Then it was applied to the protection of freeze-heave and thaw subsidence of highway in frozen soil area. Sensors were arranged to dynamically monitor the influence of polymer grouting, diffusion, expansion, and exothermic processes on different layers of frozen soil. The results showed that the thermal conductivity of low exothermic polymerwas affected by density, the higher the density, the higher the thermal conductivity. The maximum temperature, maximum displacement, and maximum pressure of polymer grouting on each layer were less than 36 °C, 1.4 mm, and 280 kPa, respectively, and the soil of each layer recovered to its initial state 60 min after grouting was completed. Polymer grouting had significant effects on the artificial road bases with a depth of more than 80 cm, and the affected depth of semi-rigid bases was less than 40 cm. Because of serious damage in the driving direction, the grout preferentially diffused to the driving side. Therefore, repairing roadbed diseased in the permafrost region using a low-exothermic polymer is feasible.