磷矿渣改性水泥基充填料的渗透性能及其微观结构

    Permeability and Microstructure of Phosphate Slag Modified Cement-Based Filling Material

    • 摘要: 这是一篇陶瓷及复合材料领域的论文。采用碱激发混合法制备了4种不同磷矿渣掺量的水泥基充填料,对养护过程中的改性充填料开展渗透率、核磁共振(NMR)与电子显微镜扫描(SEM)实验。结果表明:随磷矿渣掺量增加,水泥基充填料试件的抗压强度呈现先增后减的变化趋势,渗透率呈现先减后增的非线性变化趋势,且两者均在4%时达到极值;经过养护1~28 d的充填料试件弛豫时间(T2)分布曲线均为双峰分布,代表小孔隙的峰占比超过80%,代表大孔隙的峰占比随养护时间增加而逐渐降低;根据SEM图像可以看出一定掺量的磷矿渣能够促进水化反应的发生,使得材料的孔隙显著减少;磷矿渣为4%时,水泥基充填料的密实度较好,抗渗性能和强度达到较佳,据此可以确定磷矿渣改性水泥基充填料的较佳掺量是4%。

       

      Abstract: This is an article in the field of ceramics and composites. In order to improve the impermeability and microstructure of the impermeable wall materials, four kinds of calcium-based bentonite modified and filling material with different dosages were prepared under the action of alkali excitation reaction. The modified and filling material samples in the curing process were tested by flexible wall penetration (FWPT), nuclear magnetic resonance (NMR) scanning and electron microscope scanning (SEM). The results show that the permeability coefficient of filling material samples decreases first and then increases with the increase of bentonite content, and reaches a minimum value when the content of bentonite is 4%. The relaxation time (T2) distribution curves of the filled material specimens after curing from 1 to 28 d were all bimodal, with more than 80% of the peaks representing small pores, and the percentage of the peaks representing large pores decreasing with the increase of curing time. According to SEM images, it can be seen that a certain amount of calcium bentonite can promote the occurrence of hydration reaction, and the porosity of the material is significantly reduced. At 4% phosphate slag, the cementitious filler has the best compactness and better impermeability and strength. Accordingly, it can be determined that the better dosage of phosphate slag modified cementitious filler is 4%.

       

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