气泡结构调控组分对引气砂浆流动度及抗压强度的影响

Effect of Bubble Structure Modifying Agent on Fluidity and Compressive Strength of AirEntrained Mortar

摘要:

选取两种代表性气泡结构调控组分，分析不同类型气泡结构调控组分对引气砂浆流动度及抗压强度的影响规律，通过对硬化砂浆孔结构特征参数和液体表面张力的测试分析，揭示气泡结构调控组分对引气砂浆流动度及抗压强度的作用机理.结果表明，增稠型调控组分环糊精通过提高砂浆液相黏度来延缓引气过程，使砂浆中的气泡（孔）细化，提高10~200 μm孔径的孔隙率，从而增大砂浆的流动度，提高其抗压强度；抑泡类调控组分聚醚硅氧烷共聚物取代液膜表面引气剂分子，降低液膜局部表面张力，低掺量下使大气泡细化成为小气泡，高掺量下气液界面膜强度降低，气泡不能稳定存在，此时总孔隙率降低，导致砂浆流动度先增后减，抗压强度不断提高.

Abstract:

Two representative kinds of bubble structure modifying agents were selected to study the effect of different types of bubble structure modifying agent on the fluidity and compressive strength of the airentrained mortar. The mechanism of the bubble structure modifying agent on the fluidity and compressive strength of the airentrained mortar was researched by testing pore structure parameters of the hardened airentrained mortar with bubble structure modifying agent and the surface tension of the liquid. The results show that the viscosity modifying agent, cyclodextrin (βCD), can delay the airentraining process by increasing the liquidphase viscosity of the mortar, so that the bubbles (pores) in the mortar can be refined, the porosity of air void size ranging from 10 μm to 20 μm can be raised, and the fluidity and compressive strength of the mortar can be increased. The antifoaming agent, siloxane polyether copolymer (PSPEO), can replace the airentraining agent molecules on the surface of the bubbles film and reduce the local surface tension. The big bubbles are refined into small bubbles with lowdosage PSPEO, while the strength of the gasliquid interface film is reduced, bubbles cannot exist stably with highdosage PSPEO and the total porosity is lowered. Therefore, the fluidity of the mortar first increases and then decreases, and the compressive strength continuously increases.