Preparation and performance of multifunctional pumping wet shotcrete with the inclusion of microencapsulated phase change material

To realize the triple functions of “roadway support, thermal insulation and heat regulation” of pumping wet shotcrete (PWS), the microencapsulated phase change material (MPCM) with poly (lauryl methacrylate) as shell and paraffin wax as core was synthetized by interfacial polymerization. The surface morphology, particle size distributions, core-shell compositions, the performances of the thermal stability and phase change of the MPCM were analyzed. The results show that the synthetized MPCM has excellent performances and can be applied in PWS. To obtain the optimal mixed proportions of the key materials (i.e., ceramsite, sand and MPCM) in PWS, the key performance indices were employed in the orthogonal experimental design to test the multiple performances of the PWS containing MPCMs. The results show that these performances are influenced by the dosages of the key materials and the recommended dosages were: 112.5 kg/m3 of ceramsite, 1250 kg/m3 of sand and 100 kg/m3 of MPCM. This study shows that the application of the MPCMs cannot only further reduce the thermal conductivity of PWS but also endow PWS with the function of heat regulation. A broad prospect of the application of MPCMs in underground cooling engineering can be expected.