铜尾矿掺合料在预拌混凝土中应用研究

Research on application of copper tailings admixture in ready-mixed concrete

采用铜尾矿掺合料替代粉煤灰制备C30~C50预拌混凝土,研究铜尾矿掺合料对预拌混凝土工作性能、抗压强度及抗碳化性能的影响。结果表明,铜尾矿掺合料完全替代粉煤灰作为掺合料,混凝土的初始坍落度可达215~230 mm,初始扩展度可达570~600 mm,1 h坍落度损失0~15 mm,1 h扩展度损失5~20 mm,满足运输、泵送与施工要求;与对照组相比,早期强度提高较快,后期强度提高较慢,抗碳化性能得到提升。XRD与SEM分析表明,铜尾矿掺合料的掺入,在水化过程中无新的晶体生成,早期水化生成大量的氢氧化钙,后期则生成较多的钙矾石,使得浆体更加密实,且铜尾矿掺合料与矿粉复合效果优于铜尾矿掺合料与钢渣粉的复合。

Copper tailings powder was used as an admixture instead of fly ash to mix C30~C50 concrete,and the effects of copper tailings admixture on the work performance,compressive strength and anti-carbonation of premixed concrete were studied.The results show that if the fly ash is completely replaced by copper tailings powder as admixture,the initial slump of concrete can reach 215~230 mm,the initial expansion can reach 570~600 mm,the slump difference after 1 h is 0~15 mm,and the expansion difference is 5~20 mm,which satisfies the requirements of transportation,pumping and construction;compared with the control group,the early strength growth rate is faster,the later strength growth rate is slower,and the anti-carbonation performance is also improved.The test results of XRD and SEM show that the incorporation of copper tailings admixtures does not produce new crystals during the hydration process.A large amount of calcium hydroxide is generated during early hydration,and more ettringite is generated in the later period,which makes the slurry more dense,and the compounding effect of copper tailings powder and slag powder is better than that of copper tailings powder and steel slag.