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

The frost heave disease of cement-based grouting materials occurred in the pre-stressed pipeline in alpine re-gions. 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 degrees C, and relevant experiments determine the dosage of silica fume to improve its fluidity. Secondly, experiments carried out at-5 degrees 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 re-quirements in the hostile temperature environment in the Qinghai Tibet Plateau and other Alpine regions.