硅酸盐水泥水化动力学模型与试验方法研究进展

水泥水化过程决定水泥基材料强度、耐久性等诸多性能，深入理解水泥水化机理具有重要的科学意义和工程价值。本工作回顾了硅酸盐水泥水化动力学模型的最新研究进展，评述了GEMS热力学计算、HymoStruc3D和CEMHY3D等水化数值模拟方法及其局限性，总结了准弹性中子散射和核磁共振等先进测试手段在研究水泥水化过程中水态演变和孔结构发展中的具体应用，提出了该领域未来研究的趋势和挑战。     

聚丙烯酰胺对水泥砂浆塑性收缩开裂性能的影响

通过测试水分蒸发速率、塑性抗拉强度、塑性收缩应力、抗裂指数和塑性收缩开裂权重值,研究了不同掺量(质量分数,下同)聚丙烯酰胺(PAM)增稠剂对水泥砂浆塑性阶段收缩开裂性能的影响.结果表明:PAM对水泥砂浆塑性收缩开裂有较好的减裂效果,随着PAM掺量的增加,在大风速下水泥砂浆水分蒸发速率总体上呈现减小趋势,但当PAM掺量大于0.08%时,水泥砂浆水分蒸发速率有所回升;水泥砂浆塑性抗拉强度和塑性收缩应力均随着PAM掺量的增加而减小,当PAM掺量达到0.06%后不再减小;随着PAM掺量的增加,水泥砂浆抗裂指数呈增大趋势,塑性收缩开裂权重值呈明显减小趋势.     

Self-regulating Humidity Activated Carbon Material Prepared from Bamboo for the Room

A self-regulating humidity material with bamboo for the room was prepared. The activated carbons were prepared with the temperature rising rates of 5, 10, 15, 20 ℃/min and constant temperatures of 600, 700, 800, 900, 1 000, 1 100, 1 200, 1 300, 1 400, and 1 500 ℃ for 0.5, 1, 2, 3, and 6 h, respectively.And then their structures such as specific surface areas, volumes of pores from 3.7-7.1 nm and average pore diameters were tested. Various humidity conditions were simulated and their self-regulating humidity properties such as absorption/desorption contents, rates and stabilities were evaluated. The results show that the specific surface area, volume of pores from 3.7-7.1 nm and average pore diameter of activated carbon are closely nonlinearly related to the temperature rising rate, temperature and holding time. In general, the activated carbon prepared with the temperature rising rate of 5 ℃/min and kept at 1 100 ℃ for 2 h has the highest absorption/desorption content and rate, the lowest decay factor and then the best stability at all humidity for the fact that it is provided with proper average pore diameter, higher specific surface area and volume of pores from 3.7-7.1 nm. The activated carbons can be prepared with the temperature rising rate of 5 ℃/min and kept at 1000, 900,1 200, 1 300, 1 400, 1 500, 800, 700, and 600 ℃ respectively for 2 h. These resulted properties are attributed to their different average pore diameters and volumes of pores from 3.7-7.1 nm.     

氧化钾对硅酸二钙和无水硫铝酸钙矿物形成的影响

目的 为研究K2O对高硅贝利特硫铝酸盐水泥主要矿物C2S和C4A3S的影响，为含有钾的低品位矿物原料生产高硅贝利特硫铝酸盐水泥奠定了基础．方法 采用f-CaO分析、热分析方法．结果 少量的K2O，降低了f-CaO的质量分数，降低了CaCO3的分解温度及矿物的合成温度．结论 适量的K2O，有利于f-CaO的吸收，降低了C2S和C4A3S矿物及C2S和C4A3S复合矿物合成温度。加速了高硅贝利特硫铝酸盐水泥矿物的形成；除K2O的作用外。复合矿物的相互作用也对这两种矿物的生成尤其是C2S的生成起了一定的促进作用．     

Influence of sugar filter mud on formation of portland cement clinker

To explore the mechanisms of filter mud (FM) in the portland cement clinker formation, and to make effective use of FM in the cement production as lime-based raw materials, the influences of FM on the apparent activation energy of calcium carbonate decomposition, liquid phase amount, crystalline phase and tricalcium silicate polymorphism were investigated by TA, SEM and XRD. The experimental results show that FM can reduce apparent activation energy of calcium carbonate decomposition, and increase liquid phase amount. Appropriate FM replacement ratios are useful to promoting the C₃S formation and heightening the C₃S content. New phases of α-C₂S and C₂S·0.5Ca₃ (PO₄)₂ can be found in the clinkers while the ratios are above 15%. In addition, impurities in FM can induce the C₃S polymorph to transform.     

不同氧化铜掺量下硅酸三钙矿物的形成

通过非等温差示扫描量热分析和扫描电子显微镜,结合CuO-CaO系统相图,研究CuO在CaCO3和SiO2混合物中的掺量(质量分数)对硅酸三钙(C3S)矿物形成机理的影响.用X射线衍射分析了最终烧制试样的多晶型组成.结果表明:在C3S矿物形成的过程中,少量CuO的加入并没有显著地影响到CaCO3分解表观活化能.但是CuO的加入为C3S矿物的形成提供了液相,增加了液相量,液相的主要成分约80%为CuO.CuO的加入对C3S矿物的晶型产生了显著的影响.当试样中掺入0,1.0%,1.5%,2.0%CuO时,C3S多相体为T型;当试样中掺入0.5%CuO时,C3S多相体为R型;当试样中掺入3%CuO时,C3S多相体为M型.     

不同空隙率沥青混合料的形变及破坏

实验研究了不同空隙率沥青混合料的形变及破坏.结果表明:在所加载的压力范围内,空隙率为1.5%,2.5%,4.5%(体积分数,下同)时,沥青混合料的间接抗拉刚度模量与荷载成直线关系,沥青混合料呈弹性体;空隙率为8.0%,10.0%,12.0%时,沥青混合料的间接抗拉刚度模量与荷载呈非线性关系,并且在二者的关系曲线中出现一个拐点,沥青混合料会出现塑性变形.不同空隙率的沥青混合料具有不同的永久变形变化过程,其压实度对间接抗拉强度有显著影响.断面分析结果显示:空隙率为1.5%,2.5%,4.5%的沥青混合料破坏的同时将会有大骨料的断裂,而空隙率为8.0%,10.0%,12.0%的沥青混合料的破坏则表现为沥青砂(由小骨料、填充料及沥青等组成)的破坏.     

不同SO3掺量下C3S矿物的形成

通过化学分析,应用等温煅烧的方法对不同SO3掺量为(0%,1%,2%,3%,3.5%,5%)的C3S矿物形成过程从动力学角度进行了系统探讨.通过拟合得到了C3S矿物形成的动力学模型,并根据该动力学模型对不同SO3掺量下C3S矿物形成的速率常数进行了计算.结果表明:在1450℃,不同SO3掺量下,C3S矿物形成由三维球形对称扩散动力学模型f(a)=(1-3√(x+y)2控制;随着SO3加入量的增加,C3S矿物形成的速率常数呈非线性变化;从游离CaO的含量和反应速率常数的角度来说,SO3的加入有利于C3S的形成.并且SO3加入量的增加有利于C3S的多相体M1的稳定.     

MgO对C2S矿物形成的影响

通过化学分析和差热分析试验手段,分别测定了试样中f-CaO的含量(质量分数,下同)和试样在烧成过程中的热变化曲线,并以试样中f-CaO的含量作为反应进度的量度,研究了MgO对高C3S水泥熟料矿物———C2S的影响.化学分析和差热分析试验结果显示,MgO的加入降低了试样中f-CaO的含量,降低了CaCO3的分解峰温和C2S矿物形成的初始温度.热力学函数计算分析显示,MgO的加入增大了n(CaO)/n(SiO2)比值,从而增大了矿物形成的反应自由能数值.     

Property and Degradation Characteristics of Concrete Prepared with Aggregate Contained Montmorillonite

To evaluate the property and degradation characteristics of concrete prepared with aggregate contained montmorillonite, concretes were prepared with aggregates contained montmorillonite, and then concrete slump loss, compressive strength, electric flux, the resistance to carbonization, freezing-thawing and sulfate attack were evaluated. The results show that montmorillonite appearance alters concrete slump loss and compressive strength. But montmorillonite increases electric flux and compactness. The carbonization, freezingthawing and sulfate attack results indicate that montmorillonite enhances carbonization depth, increases mass loss after 300 cycle freezing-thawing, as well as mass loss after sulfate attack. Overall, it is adverse to the concrete resistance to the carbonization, freezing-thawing and sulfate attack.