Department of Civil and Environmental Engineering, Yonsei University, Seoul 120-749, Republic of Korea.
Department of Civil and Environmental Engineering, Western University, London, ON, Canada N6A 5B9.
J Hazard Mater. 2014 Jul 15;276:323-31. doi: 10.1016/j.jhazmat.2014.04.060. Epub 2014 May 22.
This paper studies the changes in thermal conductivity, temperature, and unconfined compressive strength of gold tailings and fly ash mixtures during the curing period of 5 days. The microfabric of the cured mixtures was investigated with mercury intrusion porosimetry (MIP). The mixture samples were prepared at their maximum dry unit weight and optimum moisture content. Effect of adding fly ash to gold tailings (i.e., 0, 20, and 40% of the dry weight of tailings) was examined, and a comparison was made on samples prepared at the same fly ash content by replacing gold tailings with humic acid (i.e., gold tailings and humic acid ratios of 100:0, 90:10, and 80:20 by weight) or by varying pore fluid chemistry (i.e., water and salt solutions of 1M NaCl and CaCl2). The results show that the initial thermal conductivity of the samples is sensitive to the mixture proportion and a declination in the thermal conductivity is observed due to hydration of fly ash and evaporation. Inclusion of fly ash and salts into gold tailings improves the unconfined compressive strength but the presence of humic acid in samples leads to the decrease of the strength. MIP results reveal the pore structure changes associated with the packing states of the samples that reflect the influential factors considered.
本文研究了金尾矿和粉煤灰混合物在 5 天养护期内导热系数、温度和无侧限抗压强度的变化。采用压汞法（MIP）研究了固化混合物的微观结构。混合物样品按最大干单位重量和最佳含水量制备。考察了向金尾矿中添加粉煤灰（即尾矿干重的 0%、20%和 40%）的效果，并比较了用腐殖酸代替金尾矿（即尾矿与腐殖酸的重量比为 100:0、90:10 和 80:20）或通过改变孔隙流体化学性质（即 1M NaCl 和 CaCl2 盐溶液）在相同粉煤灰含量下制备的样品。结果表明，样品的初始导热系数对混合物比例敏感，由于粉煤灰的水化和蒸发，导热系数下降。粉煤灰和盐的掺入提高了金尾矿的无侧限抗压强度，但样品中腐殖酸的存在导致强度降低。MIP 结果揭示了与样品堆积状态相关的孔隙结构变化，反映了所考虑的影响因素。
