Stratified damage characteristics of high-water quick-setting material exposed to sulfate under dry-wet cycles

摘要

The stability of the grouting material under the coupling effect of sulfate attack and dry-wet cycles is essential to engineering safety. As a novel grouting material, the stability research of high-water quick-setting material (HWQSM) under different corrosive environments is in the initial stage. Moreover, the stratified damage characteristics (SDC) of HWQSM under sulfate attack were not fully explored. To this end, the strength degradation and SDC of HWQSM exposed to three kinds of sulfate solutions (i.e., 10% MgSO4 solution, 10% Na2SO4 solution, and hybrid solution of 5% Na2SO4 and 5% MgSO4) and dry-wet cycles were analyzed by using ETM-C mechanical testing machine, scanning electron microscopy (SEM), XRD, and AFM. The results show that the strength reduction rate, the thickness of the corrosion layer, and roughness between the corrosion layer and the transition layer of HWQSM are all positively correlated with the concentration of Mg2+ in the erosion solution for the increase in dry-wet cycles. Under the combined action of ion erosion and carbonization, the pores and cracks of the corrosion layer expand, which would reduce the permeability resistance but increase the erosion damage rate. This research furnishes new views into the SDC of HWQSM under sulfate attack and dry-wet cycles, which would deeper our understanding to this special material undoubtedly; the research results are expected to furnish theoretical guidance of HWQSM resistance to different sulfate solutions.