C40预拌锂渣再生骨料混凝土试验性能研究

发布时间：2018-08-17 19:57

【摘要】：废弃混凝土作为建筑行业发展进程中不可避免的产物之一,通过再生骨料混凝土技术既可避免其在埋填、远郊堆弃时对生态环境的不利影响,也能促使行业的可持续循环发展。而锂渣粉是工业制碳酸锂时排出的废渣,直接排放也会污染环境,但将其作为掺合料掺入再生骨料混凝土,既降低了混凝土成本,也减轻了对环境的压力,还充分促进了工业“双废”的利用,对混凝土性能也有一定提升。本文试验将乌鲁木齐地区收集所得废弃混凝土处理成再生骨料,并将工业废渣锂渣粉烘干磨细作为掺合料,按照一定配合比配制成掺锂渣再生骨料混凝土,并选取水灰比、锂渣掺量、再生骨料掺量三因素进行全排列试验设计,进行变量变化对其和易性与基本力学性能相关影响的讨论,并在试验结果中选取较优配比,进行抗氯离子性能、抗冻融性能的验证性试验,得到最优配比。结果如下:(1)掺锂渣再生骨料预拌混凝土可以达到施工的泵送要求,相同条件下,由着再生骨料、锂渣掺量的增加,其和易性能持续下降,而骨料取代率在50%以内时,对和易性有一定程度的降低但影响不大,整体影响为随着再生骨料掺量的增加,和易性变差。(2)在相同水灰比下,早期强度锂渣掺量为10%,再生骨料取代率在50%的试块的立方体抗压强度最高,同试劈裂抗拉强度也最高,当龄期为28d时锂渣掺量为20%,再生骨料取代率为50%的混凝土立方体抗压强度、轴心抗压强度最高,劈裂抗拉强度也最高。(3)立方体抗压强度与轴心抗压强度比值的变化呈线性关系,其转换关系可按照本文推荐公式fc=1.0704fcu-11.9744进行计算,fcu和fts的转换关系可按本文推荐公式fts=0.1644fcu0.8044计算,但相应的适用性仍需要深入探究。(4)水灰比与掺锂渣再生骨料混凝土的耐久性能负相关。再生骨料取代率为30%、锂渣掺量为20%时,混凝土的抗氯离子性能、抗冻融性能最优,且再生骨料取代率为50%、锂渣掺量为20%时与其相差不大,均能达到普通混凝土耐久性的使用要求。
[Abstract]:Waste concrete is one of the inevitable products in the development of construction industry. The recycled aggregate concrete technology can not only avoid its adverse effects on the ecological environment when it is buried and abandoned, but also promote the sustainable development of the industry. Lithium slag powder is the waste residue discharged from the industrial production of lithium carbonate. Direct discharge will also pollute the environment. However, adding it to recycled aggregate concrete as an admixture not only reduces the cost of concrete, but also reduces the pressure on the environment. It also promotes the utilization of industrial double waste and improves the performance of concrete. In this paper, the waste concrete collected in Urumqi area is treated into recycled aggregate, and the industrial waste lithium slag powder is dried and ground as admixture. According to a certain mix ratio, the recycled aggregate concrete is prepared, and the water-cement ratio is selected. Three factors, lithium slag content and recycled aggregate content, were designed for full arrangement test, and the influence of variation of variables on the relationship between their easiness and basic mechanical properties was discussed. In the test results, the optimum ratio was selected to carry out the chloride ion resistance. The optimum ratio was obtained by the verification test of the freeze-thaw resistance. The results are as follows: (1) the pre-mixed concrete of recycled aggregate with lithium slag can meet the pumping requirements of construction. Under the same conditions, with the increase of the amount of recycled aggregate, the performance of recycled aggregate and its easy performance continue to decline, and the replacement rate of aggregate is less than 50%. The overall effect is that with the increase of recycled aggregate content, and the ease becomes worse. (2) under the same water-cement ratio, When the amount of lithium slag in the early stage is 10, the cube compressive strength of the test block with 50% replacement ratio of recycled aggregate is the highest, and the tensile strength of splitting is also the highest. When the age is 28 days, the cubic compressive strength of concrete with 20% lithium slag and 50% replacement ratio of recycled aggregate has the highest axial compressive strength and the highest splitting tensile strength. (3) the ratio of cube compressive strength to axial compressive strength is linearly related to the ratio of cubic compressive strength to axial compressive strength. The conversion relationship between FCU and fts can be calculated according to the recommended formula fc=1.0704fcu-11.9744 in this paper, but its applicability still needs to be further explored. (4) the water-cement ratio is negatively correlated with the durability of recycled aggregate concrete with lithium slag. When the ratio of replacement of recycled aggregate is 30 and the content of lithium slag is 20, the concrete has the best resistance to chloride ion and freezing and thawing, and the replacement ratio of recycled aggregate is 50%, and when the amount of lithium slag is 20, there is no difference between them. Can reach the ordinary concrete durability requirements.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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