超细钢渣粉对硅酸盐水泥浆体流变性能的影响

为了研究超细钢渣粉对水泥浆体流变特性的影响,实验制备了中值粒径分别为5.0 μm和3.3 μm的超细钢渣粉,探究超细钢渣粉粒度和掺量对水泥浆体流变特性的影响规律.结果 表明,超细钢渣的掺入显著降低了超细钢渣-水泥复合体系的流动度,当掺入量为30％时其流动度基本丧失.超细钢渣-水泥复合浆体仍属于Bingham流体,且存在明显的剪切稀化现象,超细钢渣的粒径降低会导致屈服应力、塑性粘度升高,最大增幅分别为87.3％和276.7％.机械搅拌可明显降低浆体的表观粘度,40％的3.3 μm超细钢渣取代水泥的样品经过480 s的均速剪切,其表观粘度从4.291 67 Pa·s降至2.807 69 Pa·s,这预示着在实际应用中可以延长搅拌时间来缓解超细钢渣掺入后对工作特性带来的不利影响.     

再生微粉对海工混凝土抗氯离子侵蚀性能影响的研究

混凝土预拌厂废渣与其它废渣粉磨制备再生微粉,采用RCM法研究再生微粉对混凝土氯离子扩散系数的影响规律,同时制备相应水泥净浆,通过XRD、SEM、MIP、EDS等测试方法分析其作用机理。结果表明,再生微粉可显著减小海工混凝土氯离子扩散系数。再生微粉减少了水化产物中Ca(OH)_2含量,生成了低钙硅比的C-S-H凝胶,同时优化了孔结构,提高了海工混凝土的抗氯盐侵蚀性能。     

人工海水环境中浆状掺合料混凝土抗化学侵蚀性能

采用湿磨处理工艺制备一系列细度的混凝土浆状掺合料,研究浆状掺合料混凝土在人工海水环境中的抗化学侵蚀性能。结果表明,不同方式处理的粉煤灰及原状粉煤灰的掺入,一般均在一定程度上改善其混凝土抗化学侵蚀性能;不同方式处理的矿渣掺合料的加入,均在一定程度上恶化了混凝土的抗化学侵蚀性能;粉煤灰同矿渣的复合能明显改善矿渣混凝土抗化学侵蚀性能差的弱点。     

建筑防水企业信息化发展与探索

从信息化对于制造行业的普遍影响出发,聚焦于建筑防水企业,并根据不同规模和处于不同发展阶段的企业自身需求,探讨信息化建设的实践过程,并且从实际案例出发,推导出用于指导建筑防水企业进行信息化建设的可借鉴方法和经验。深度探讨了信息化对于企业发展的促进作用,也揭示了在信息化发展过程中需要解决和重视的问题。     

高性能混凝土中活性微细矿渣粉的制备

活性微细矿渣粉是高性能混凝土中一种重要的胶凝材料。本文利用动磨、点活化及晶种技术，研究了较优的方案，并制备出活性较高的微细矿渣粉。     

超细化粉煤灰的活性提升

粉煤灰具有潜在活性,可作为辅助胶凝材料用于建筑材料中,但粉煤灰活性较低,限制了其应用效率.采用对粉煤灰进行超细化(d50可降至2.51μm)处理的方法以提升其潜在活性.采用激光粒度及SEM分析了超细FA的粒度分布、均匀程度及形貌特征,采用活性指数表征了超细化对FA活性的提升,并采用XRD及FTIR探讨了超细化对FA物相组成、物质结构及活性提升的影响机理.结果表明,超细化处理显著提升了粉煤灰的颗粒均匀性及早期、后期活性指数,3 d、28 d活性指数分别提升14.45％和25.49％;经超细化过后FA的产物相中可见钙矾石晶体生成,Si-O振动峰向低频高活性迁移.     

Effect of silica fume on the thaumasite form of sulfate attack on cement-based materials

Thaumasite form of sulfate attack(TSA) can be observed in cement containing limestone under sulfate condition at low temperature. Mixing with suitable mineral admixture could be a good choice to improve the TSA resistance performance of cement-based materials. We investigated the durability performance of limestone-cement mortars reinforced with silica fume(SF) in 5% MgSO_4 solution at 5 ℃. The mortars, which were immersed in aggressive condition, were prepared with 2%, 4%, 6%, 8%, and 10% cement replacement by SF at a fixed water-to-binder ratio. Appearance, compressive strength, change of length and mass and corrosion products were investigated to evaluate the TSA resistance performance of SF based specimens. The results showed that specimens in the absence of SF almost disintegrated. Increasing SF dosage can reduce the degree of deterioration of SF mortars in TSA environment. Mortar mixtures with more than 6% SF merely show slight degeneration in relation to macroscopic and microscopic tests and characterizations.     

Physico-chemical Characteristics of Wet-milled Ultrafine-granulated Phosphorus Slag as a Supplementary Cementitious Material

The phosphorus slag(PS) can be used as a supplementary cementitious material due to its potential hydrating activity. However, its usage has been limited by its adverse effects, including prolonged setting and lowered early-stage strength. In this study, we achieved ultrafine granulation of PS using wetmilling(reducing d50 to as low as 2.02 μm) in order to increase its activity, and examined the physico-chemical properties of the resulting materials, including particle-size distribution, slurry pH, zeta potential, and activity index, as well as how their replacement level and granularity affect the setting time and mechanical performance of PS-cement mixture systems. The results suggested that as the granularity increases, there are significant boosts in the uniformity of particle sizes, slurry pH, and activity index, and the effects on cement paste, including setting times, and early-and late-stage strengths, are significantly mitigated. When d_(50)=2.02 μm, the slurry becomes strongly alkaline(pH=12.16) compared to the initial d_(50)=20.75 μm(pH=9.49), and the activity is increased by 73%; when used at 40% replacement, the PS-cement mixture system can reach a 28 d compressive strength of 93.2 MPa, 36% higher than that of the pure cement control group.     

合同能源管理在公共建筑节能领域的应用

介绍现行的4种合同能源管理经营模式,建筑节能改造中墙体、屋顶和外窗的改造技术,以及合同能源管理机制在公共建筑节能领域的应用特点;并通过办公楼节能改造项目节能效益的计算,证明合同能源管理体制在我国建筑节能领域具有广阔的应用前景。     

矿物掺合料细度及掺量对水泥石渗流微结构影响的分析

在运用渗流理论分析水泥石渗流微结构的基础上,探讨了有效发挥矿物掺合料效应的问题及其本质.分析表明,未水化粒子、水化产物等固相在水泥石空间内分布特性改变是影响矿物掺合料效应有效发挥的主要因素,是矿物掺合料掺入导致水泥石宏观力学性能下降的本质原因.要有效利用矿物掺合料的各种效应,需合理地控制未水化粒子、水化产物等固相在水泥石空间内分布特性,在化学反应活性一定的情况下,需对矿物掺合料粒径、掺量进行控制.