CGA560增强助磨剂在水泥粉磨中的应用研究

研究了CGA560增强助磨剂在水泥粉磨中对台时产量和水泥质量的影响。试验结果表明:在磨机状况不改变的条件下,CGA560增强助磨剂的加入可提高磨机产量10%-30%;同时可有效减少过粉磨现象,优化水泥颗粒级配,提高了水泥粉磨细度及比表面积;因而使水泥强度等性能得到了明显改善和提高。     

复合硅酸盐水泥固化含氟污泥的试验研究

采用复合硅酸盐水泥对含氟污泥进行固化处理并制取了不同污泥掺量的水泥标准试块，考察了掺量对试块抗压强度、氟离子浸出量、物相转变和晶体形态的影响。结果表明，当含氟污泥掺量为10％时，试块强度高，氟离子浸出量低，是较为适宜的污泥掺加比例。10％掺量试块28天抗压强度达到22.2 MPa，满足一般垫层、基础、地坪及受力不大的结构强度要求；10％掺量试块在地下水和酸雨作用下的氟离子浸出量分别为0.16 mg/L和0.39 mg/L，远小于危险废物100 mg/L的标准限值，安全性较高；机理研究表明，氟化钙污泥的加入加快了水泥中C3A的水化速度，增加了早期AFt生成量，提高了试块早期强度。     

HG无机侑机复合土壤固结材料的应用研究

作为一种新型的复合材料,HG无机/有机复合土壤固结材料能提高水泥对地下淤泥质软土的加固作用.经过试验对比,结果表明:HG与水泥复配的最佳质量比例为1.5%;添加HG后水泥土试样的无侧限抗压强度、抗剪强度和抗渗透性与未添加时相比都有明显的提高,同时添加HG能明显降低水泥浆的粘度,增加了水泥浆的输送性能.     

混凝土受压构件的力学行为及设计计算

受压构件是混凝土结构课程的主要内容之一,包括轴心受压构件和偏心受压构件.通过轴心受压构件的学习,主要让学习者加深对钢筋与混凝土共同受力时的力学行为的认识;而偏心受压构件的受力状态较复杂,特别是小偏心受压学习起来有一定难度.而一般教材中对有些问题的认识存在偏颇,有些问题没有交代清楚.主要针对轴心受压构件的应力重分布、大小偏心受压的判别条件及其应用、小偏心受压的不同受力状态及其计算方法等问题作了一些较深入的探讨,以期与同行交流,同时希望对"混凝土结构"的学习有所帮助.     

Effect of grinding on chemical and physical properties of rice husk ash

The effect of grinding on the chemical and physical properties of rice husk ash was studied. Four rice husk ashes with different finenesses,i.e. coarse original rice husk ash (RHA0),RHA1,RHA2,and RHA3 were used for the study. Ordinary Portland cement (OPC) was partially replaced with rice husk ash at 20% by weight of binder. The water to binder ratio (W/B) of the mortar was maintained at 110%±5% with flow table test. Specific gravity,fineness,chemical properties,compressive strength,and porosity test of mor...     

Cemented backfill technology based on phosphorous gypsum

Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craftwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage (the mass ratio of cement to fly ash to gypsum) is 1:1:6–1:1:8 with mass fraction of solid materials 60%–63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7×10⁶ yuan (RMB), only 1/10 of that of traditional paste backfill system. Foundation item: Project (2006BAB02A03) supported by the National Key Technology Research and Development Program; Project (08MX16) supported by Mittal Scientific and Technological Innovation Projects of Central South University during 2008     

熟料粒度对骨粉/磷酸钙生物骨水泥结构与性能的影响

采用新方法首次将动物骨中的鱼骨引入到磷酸三钙和磷酸氢钙等原料体系中通过高温烧结制备磷酸钙基生物骨水泥（CPC）,以柠檬酸和柠檬酸钠的缓冲液为固化液、按一定的液固比制备固化试样,通过扫描电子显微分析（SEM）和力学性能测试等方法,研究了熟料粒度对其固化试样结构与抗压强度的影响.结果表明：制备过程中骨水泥粉末的粒度对其固化试样的微观结构及其抗压强度有着较为显著的影响,通过调整骨水泥粉末的粒度可达到优化其固化试样的微观结构和改善其力学性能的目的.     

鲍罗米公式在预测轻骨料混凝土28d强度方面的应用

研究结果表明,用鲍罗米公式推测轻骨料混凝土28 d抗压强度的误差较大.实测出不同配合比的轻骨料混凝土28 d抗压强度和相应的28 d胶砂试块抗压强度,运用多元线性回归分析的方法完善了鲍罗米公式,所得公式能较准确地预测轻骨料混凝土28 d抗压强度,具有现实指导意义.     

橡胶水泥土电阻率的变化规律

目的 研究不同因素对橡胶水泥土的电阻率的影响.方法 利用二相电极法在室内测试橡胶水泥土的电阻率.结果 随着水泥掺量的增加,橡胶水泥土的电阻率呈递增趋势;随着橡胶粉掺量的增加,橡胶水泥土的电阻率呈递减趋势.大粒径橡胶粉对橡胶水泥土电阻率的影响大于小粒径橡胶粉.结论 橡胶水泥土电阻率与橡胶水泥土无侧限抗压强度在适当的水泥掺量和橡胶掺量的情况下存在很好的相关性.可以通过对橡胶水泥土电阻率的测定来推算橡胶水泥土无侧限抗压强度的变化规律.     

基于粘聚力的沥青稳定碎石设计方法研究

针对沥青稳定碎石混合料对抗拉性能的要求,采用结合混合料抗压强度及抗拉强度的粘聚力法,确定沥青稳定碎石混合料的沥青用量,将结果与传统的马氏方法进行比较,并应用两种沥青膜厚度计算方法计算了有效沥青膜厚度,得出粘聚力法使混合料获得具有更好粘聚力的沥青膜厚,且沥青膜厚范围约为6.5μm~9.0μm。