钛石膏-矿渣对砖混再生粗集料负压强化效果评价

Effect Evaluation of Negative Pressure Strengthening of Titanium Gypsum Slag on Brick Concrete Recycled Coarse Aggregate

为了解决建筑固废资源化利用的技术难题,研究了钛石膏-矿渣浆体(T-S浆体)强化砖混再生粗集料(BCRCA)的作用机理,比较了负压强化与传统搅拌裹附强化效果的优劣,分析了T-S浆体强化水泥稳定碎石混合料无侧限抗压强度和劈裂强度的变化.结果表明:T-S浆体可以产生C-S-H凝胶和钙矾石微膨胀体,填充粗集料的孔隙;负压强化BCRCA的压碎值达到27.5%,吸水率降低至6.6%,表观密度提高至2.678 g/cm^(3),灌入饱和度相较于传统搅拌裹附强化提高了63.7%;负压强化水泥稳定碎石混合料的无侧限抗压强度为3.8 MPa,劈裂强度为0.40 MPa,较未强化时分别提高38.5%、36.7%,抗疲劳性与抗冲刷性均提升了15%以上,强化效果明显.

To solve the technical difficulty in the utilization of construction waste resources,the mechanism of strengthening of the brick concrete recycled coarse aggregate(BCRCA)by titanium gypsum slag paste(T-S paste)was studied.Both of the advantages and disadvantages of negative pressure strengthening and traditional strengthening were discussed.At the same time,the variation rules of unconfined compressive strength and splitting strength used for the cement stabilized macadam mixture were analyzed.The results show that the T-S paste can produce C-S-H gel and ettringite micro expansion body to fill the coarse aggregate pores.After negative pressure strengthening,the crushed stone value of BCRCA reaches 27.5%,the water absorption ratio decreases to 6.6%,and the apparent density increases to 2.678 g/cm^(3).The water saturation after negative pressure strengthening is 63.7%higher than that after stirring.After negative pressure strengthening,the unconfined compressive strength and the splitting strength of cement stabilized macadam mixture are 3.8 MPa and 0.40 MPa respectively,increasing by 38.5%and 36.7%compared with those unstrengthened.Both fatigue performance and anti-scouring performance increase by more than 15%.The strengthening effect of T-S paste is obvious in the negative pressure strengthening mode.