生态型稻壳灰超高性能水泥基复合材料的制备及机理分析

发布时间：2018-07-12 21:31

  本文选题：超高性能水泥基复合材料 + 稻壳灰　； 参考：《东南大学》2015年硕士论文

【摘要】：生态型超高性能水泥基复合材料(ECO-UHPFRCC)采用矿物掺合料多元复合技术,充分发挥优势互补效应,有效降低了UHPFRCC的成本。本文在前人研究的基础上,研究采用稻壳灰替代硅灰以提高ECO-UHPFRCC性能的可行性。对制备得到的稻壳灰进行活性测试,并系统分析了稻壳灰对水泥基材料的流动性能、力学性能、微观结构以及水化的影响,揭示了稻壳灰对ECO-UHPFRCC性能影响的规律。对制备得到的稻壳灰性能测试,采用X射线衍射技术分析物相、扫面电镜分析稻壳灰结构、电导率以及热分析测试稻壳灰的反应活性。结果表明：稻壳灰650℃灼烧1h能够得到主要成分为无定形Si02的灰分。稻壳灰为片状、蜂窝状多孔结构,层片结构由几十到几百个纳米的Si02颗粒堆积而成。稻壳灰活性的源于无定形Si02的灰分以及其内部特有的多孔结构。稻壳灰早期活性指数大于硅灰,随着龄期延长火山灰反应,稻壳灰和硅灰28d活性指数接近。对不同稻壳灰掺量的低水胶比浆体进行流动度试验和流变学分析。结果表明：稻壳灰掺入后低水胶比浆体粘度以及屈服应力增加,而硅灰在不大于10%掺量能够降低浆体粘度和屈服应力；20%硅灰、稻壳灰复合掺量下,稻壳灰硅灰各10%掺量净浆屈服应力以及粘度值最低,从优势互补的角度应该选择稻壳灰和硅灰复掺。20%硅灰、稻壳灰复合掺量下,砂浆流动性随着砂胶比增大而下降；钢纤维掺量0%增加到2%,钢纤维对流动性的影响不大。当钢纤维掺量大于2.0%后,浆体流动度快速下降,钢纤维掺量基准体积掺量定为2%。对硅灰和稻壳灰复掺掺量、钢纤维体积率和砂胶比对UHPFRCC的抗折抗压强度的影响进行分析。综合试验结果,在85℃蒸汽养护条件下制得的最高抗压强度为199MPa,其配合比为0.165水胶比、30%掺量粉煤灰、10%掺量硅灰、10%稻壳灰、3%体积率钢纤维、1.0砂胶比。稻壳灰部分替代硅灰能够明显提高超高性能水泥基复合材料抗压强度。断裂韧性试验表明：10%掺量稻壳灰和10%掺量硅灰复掺提高了水泥基材料的断裂韧度、断裂能；20%固定复掺量下,R10SF10体系具有最低屈服应力和粘度值,屈服应力小有利于纤维的良性能取向而提升试件弯折性能。纤维体积掺量1%增大到2%,基体的断裂能增大超过100%,纤维体积掺量大于2%增强效应不明显。形貌以及孔结构分析结果表明：UHPFRCC的基体与集料及基体与钢纤维之间都没有明显界面过渡区；稻壳灰和硅灰复掺后,UHPFRCC小毛细孔减少、凝胶孔增多,超高性能水泥基材料基体有非常高的密实度。水泥水化热实验和基于XRD定量分析结果表明稻壳灰能够提高早期水泥水化程度,复掺稻壳灰、硅灰对水泥水化程度提高更明显。
[Abstract]:Ecotypic ultra-high performance cement matrix composites (ECO-UHPFRCC) adopt mineral admixture multicomponent composite technology to give full play to the advantage complementary effect and effectively reduce the cost of UHPFRCC. On the basis of previous studies, the feasibility of using rice husk fume instead of silica fume to improve the performance of ECO-UHPFRCC was studied. The effects of rice husk ash on the fluidity, mechanical properties, microstructure and hydration of cement-based materials were systematically analyzed, and the effects of rice husk ash on ECO-UHPFRCC properties were revealed. The phase of rice husk ash was analyzed by X-ray diffraction technique. The structure, conductivity and reaction activity of rice husk ash were analyzed by scanning electron microscope (SEM). The results showed that the main component of rice husk ash was amorphous Si02 when it was burnt at 650 鈩，

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