A New Kind of Eco-Cement Made of Cement Kiln Dust and Granular Blast Furnace Slag

1 IntroductionThe kiln dust is the solid waste collected fromce-ment kilns .Its chemical composition is similar to that ofcement raw meal , but the potassuim,sodium, chlorineand sulfur content and the lime saturation coefficient aremuch higherthanthose of the cement rawmeal[1].Ontheother hand,the binding water of it is relatively lowandthere are some clinker minerals . Generally,cement kilndust can be classifiedintotwo categories .One isthe dustfromdry process rotary kilns (without preheater …     

集料级配对多孔混凝土透水基层材料性能的影响

研究了0—4.75 mm颗粒的比例,粗集料最大粒径以及9.5—4.75 mm颗粒在粗集料中的比例对多孔混凝土透水基层抗压强度的影响。研究表明:即使多孔混凝土透水基层的水泥用量仅150 kg/m3,当4.75 mm通过率控制为10%—15%的条件下,所配制的多孔混凝土透水基层不仅具有较高的强度,还具备了良好的透水性能;最大粒径增加,强度降低,透水性增加;粗集料的9.5 mm通过率控制在20%左右时,颗粒粒子之间基本没有干涉,配制的多孔混凝土透水基层强度最大。     

道路基层复合胶凝材料的性能调控

研究了熟料钢渣粉煤灰磷石膏系道路基层复合胶凝材料的凝结时间、胶砂强度和膨胀性能的调控,分析了其缓凝微膨胀机理.结果表明：磷石膏中的可溶性杂质会与Ca2+和OH-反应,生成难溶物覆盖在胶凝材料颗粒表面,显著延长凝结时间,磷石膏掺量每增加3%,即可延长凝结时间约65min;大掺量磷石膏可为浆体提供充足的SO2-4,保证钙矾石的大量稳定生成,使硬化浆体产生微膨胀;过量磷石膏亦会造成过大的膨胀,破坏硬化浆体结构,通过加入适量钢渣取代粉煤灰,可以促进复合胶凝材料的早期水化,优化孔结构,明显提高道路基层复合胶凝材料的性能.     

膨胀土固化剂的研究

以石灰为主要成分，通过掺入其它工业废渣类辅助胶凝材料，研制了一种高效膨胀土固化剂。对膨胀土固化剂的配比进行了优化，并对固化土的主要性质进行了研究。结果表明：经过配比优化后的固化剂固化膨胀土和普通的石灰固化土相比具有强度高，水稳性好，塑性和膨胀性低的特点，且固化效果良好。     

H_3 软土固化剂加固桥台基坑的研究

利用Ｈ３软土固化剂井桩法形成复合地基，对桥台基坑软土进行固化。室内试验及工程实例说明，Ｈ３软土固化剂固化土，各龄期强度均高于水泥土。推广使用Ｈ３固化剂具有一定的经济效益。     

土壤稳定专用水泥的研究

通过研究熟料率值、ＣａＣｌ２、ＳＯ３对水泥稳定土的无侧限抗压强度的影响，讨论粘土－水系统中水泥水化过程及稳定土强度形成机理，及土壤稳定水泥的合理组配。     

广西石灰岩机制砂混凝土材料设计研究

天然河砂是分布不均衡的地方性资源,岩溶地区天然砂资源十分匮乏。针对广西高速公路建设工程的实际情况,对C30～C50标号桥隧及路面机制砂混凝土进行配合比优化设计研究。结果表明,适量调整石粉限值对机制砂混凝土工作性能有明显的改善;粉煤灰的掺入有效缓解了机制砂混凝土的离析倾向,对工作性能的提高更为显著。     

粗集料嵌锁型高性能混凝土的研究

采用砂浆包覆粗集料的工艺制备出了一种粗集料能够充分接触并有效嵌锁的高性能混凝土,并与普通C60高性能混凝土作对比研究了其性能。研究表明:在此方法制备的混凝土中,粗集料的体积分数达到了59%以上,粗集料在混凝土中可充分发挥强度骨架作用,混凝土28d抗压强度达到了70～90MPa。另外,以此种方法制备的混凝土具有较高的弹性模量、较好的体积稳定性和抗氯离子渗透性能。     

The aggregate gradation for the porous concrete pervious road base material

The effects of the proportion of fine aggregate, the maximum size of the aggregate and the proportion of the 9.5 mm to 4.75 mm particle in the coarse aggregate on the properties of the porous concrete are investigated. Results indicate that the porous concrete with a cement dosage only 150 kg/m^3 has high strength and satisfying permeability when the aggregate has a passing percentage of 4.75 mm around 10% to 15%, with the increase of the maximum size of the aggregate, the strength of the porous concrete decreases and the permeability increases. When the proportion of the 9.5 mm to 4.75 mm particle in the coarse aggregate is about 20%, there are no interference among the particles by Weymouth theory, the strength of the pervious porous concrete reaches the peak value. The optimum continues gradation limit of the aggregate for porous concrete pervious road base material is recommended according to the theoretical calculation and experimental results.     

Magnesia Modification of Alkali-Activated Slag Fly Ash Cement

A new type of magnesia modification alkali-activated cement was prepared, the strength, setting time, shrinkage ratio and cracking behavior, as well as the composition and structure of the hydration product were investigated. The results indicate that the setting time of this cement is similar to that of the ordinary commercial cements; its strength reaches the standard of 42.5 degree cement, its cracking resistance has been remarkably improved because of the micro-aggregate effect of fly ash and shrinkage compensating of magnesia.