Experimental study on the mix proportion of self-heating grouting materials in alpine regions

Abstract

The frost heave disease of cement-based grouting materials occurred in the pre-stressed pipeline in alpine regions. This paper proposes a self-heating grouting material and verifies its feasibility by a series of mechanical properties and working properties experiments. Firstly, the water-cement ratio and the dosage of admixture are determined by an orthogonal test at room temperature at 5 °C, and relevant experiments determine the dosage of silica fume to improve its fluidity. Secondly, experiments carried out at −5 °C are used to analyze the influence of calcium oxide and nano-silica on the temperature of the grouting material system. Thirdly, through adiabatic temperature rise test, the exothermic contribution of calcium oxide and nano-silica heating materials in cement-based grouting material is tested, respectively, and the working performance and mechanical properties of grouting material are tested under different negative curing temperatures. Finally, the feasibility of the self-heating grouting material proposed is verified by the confirmatory test of wrapped concrete. The test results show that the self-heating grouting material under the hostile temperature can be stabilized above five degrees, and its expansion stress does not exceed the specification requirements, which can meet the construction requirements in the hostile temperature environment in the Qinghai Tibet Plateau and other Alpine regions.