冻融循环下掺合料对大坝混凝土性能影响

Effect of Admixtures on the Performance of Dam Concrete under Freeze-Thaw Cycle

为了解决高寒地区冻融作用对大坝混凝力学性质造成的劣化问题,以抗冻基本理论为基础,设定含有纳米材料的混凝土配合比,活性高、尺寸小的纳米材料优化了混凝土的结构,提高了混凝土的抗冻性。同时,开展了劈裂试验和抗压试验,研究冻融循环下纳米材料对混凝土力学性能的影响规律。结果表明,纳米材料的增加可减少混凝土中水和水泥的用量,其中每立方米水泥降低9kg,用水量减少7kg,可大大降低大坝工程的材料成本;纳米材料能有效提高混凝土的劈拉强度和抗压强度,对混凝土起到较好的改良效果,并且冻融循环并不会对这种提高效果造成影响,但纳米材料不能抑制冻融对混凝土的劈裂劣化程度。研究成果可为类似大坝工程建设提供参考与借鉴,具有一定的指导意义。

In this paper, in order to solve the problem of deterioration of concrete mechanical properties of dams caused by freezing and thawing in cold regions, concrete proportions containing nanomaterials were set based on the basic theory of anti-freezing, and nanomaterials with high activity and small size optimized the structure of concrete and improved the anti-freezing properties of concrete. Splitting tests and compressive tests were carried out to study the law of the effect of nanomaterials on the mechanical properties of concrete under freeze-thaw cycles. The results show that the increase of nanomaterials can reduce the amount of water and cement in concrete, in which the cement per cubic meter is reduced by 9 kg and the water consumption is reduced by 7 kg, which can greatly reduce the material cost of the dam project;nanomaterials can effectively improve the splitting strength and compressive strength of concrete, which has a better improvement effect on concrete, and the freeze-thaw cycle does not affect this improvement effect However, nanomaterials do not inhibit the degree of splitting deterioration of concrete by freeze-thaw. This study provides a valuable reference for the construction of dams in the region and has certain guiding significance.