石灰石硅酸盐水泥的水化反应特性

为生产环境型水泥,用石灰石粉(简称LSP)置换部分水泥熟料的方法进行了实验。结果表明,C3S的初期水化反应率随LSP的置换率和粉末度的增加而增加,但龄期28 d的水化反应率与普通水泥(简称OPC)基本持平;C3A的初期水化反应率明显下降,但龄期3 d以后就显示出与OPC相同的反应率;碳酸钙主要在龄期7 d之内参与反应生成Monocarbonate,且与C3A水化反应有着密切的相关关系,此后几乎不参与反应。     

硅酸盐-硫铝酸盐水泥混合体系的试验研究

研究了不同比例的硅酸盐、硫铝酸盐水泥混合体系的凝结时间、水泥砂浆的强度性能,并对一定混合比例的OPC-SAC水泥进行了XRD、SEM和水化量热测试。结果表明,硅酸盐水泥与硫铝酸盐水泥混合,SAC中的C4A3-S矿物与OPC中的C3S矿物在共同水化过程中有相互促进的作用,会使混合水泥水化和凝结加速;混合水泥的强度性能与两种水泥的混合比例有关。本研究可对硅酸盐-硫铝酸盐水泥混合体系的应用提供借鉴。     

含钡硫铝酸盐水泥的研究

含钡硫铝酸盐水泥的主要矿物组成为含钡硫铝酸钙(简写3CA·BaSO_4)、硅酸二钙(β-C_2S)以及少量的铁相。本文详细地研究了这种水泥的烧成制度和各项物理力学性能;使用x射线分析和扫描电镜分析探讨了水泥水化产物及水泥石结构。     

纳米C—S—H/PCE对硅酸盐-硫铝酸盐复合水泥凝结硬化的影响

研究了纳米C-S—H/PCE对硅酸盐-硫铝酸盐复合水泥凝结时间、早期水化历程及抗压强度的影响,采用XRD、TG、pH计和SEM等分析测试手段对早龄期水化产物和液相碱度等进行表征,探讨了纳米C-S—H/PCE对硅酸盐-硫铝酸盐复合水泥的增强机理.结果表明:掺加纳米C—S—H/PCE能有效缩短硅酸盐-硫铝酸盐复合水泥浆体初...     

萤石对含钡硫铝酸盐水泥性能的影响

利用正交实验的方法在Ｃ２．７５Ｂ１．２５Ａ３Ｓ＾－生料中掺入不同量的ＣａＦ２，以不同的烧成温度，保温时间进行烧成，并对烧成矿物各水化龄期抗压强度进行了比较。通过正交试验，发现外掺１．４％ＣａＦ２，烧成温度为１３５０℃，保温２ｈ的条件下烧成的矿物各水化龄期强度最高。基于这一结果，利用含钡工业废渣为原料且掺入适量萤石烧制出了性能更为优异的含钡硫铝酸盐水泥，还庆用ＸＲＤ，ＳＥＭ等测试手段对其形成及水化进     

硫铝酸盐“S”型瞬凝水泥

研究了一种在９５０℃左右煅炼温度下烧成的硫铝酸盐“Ｓ“型瞬凝水泥方法，该水泥具有速凝，早期强度高，微膨胀等优点，此外，这种硫铝酸盐“Ｓ”型瞬凝水泥在应用中，具有堵漏成功率高，用量少，成本低和候凝时间短等优点。     

混合材对铁铝和硫铝酸盐复合强度及孔隙率的影响

研究了不同混合材在不同掺量条件下铁铝和硫铝酸盐复合的强度发展。结果表明，掺入粉煤灰、石灰石和煤矸石混合材后，强度性能下降比硅酸盐水泥明显，原因是水泥浆体孔溶液的ｐＨ值较低，反应的热力学驱动力小，在６０℃条件下干燥６ｈ可对比测定钙矾石系统的孔隙率。     

Effect of calcium aluminate cement variety on the hydration of portland cement in blended system

Two kinds of CACs with different monocalcium aluminate（CA） contents were used in the PC/CAC（PAC） mixtures. Effects of CA and CACs on the properties of PAC were analyzed by setting times and the compressive strength tests, and also by means of calorimetry, XRD, DTA-TG and ESEM. The experimental results show that the compressive strength of the PAC mortars decreases with increasing content of CAC while it declines sharply with a higher content of CA in CAC. Compared with neat PC paste, the content of calcium hydroxide in hydrates of PAC paste decreases significantly, and the hydration time of PC is prominently prolonged. Additionally, the higher the content of CA in CAC, the more obviously the hydration of PC is delayed, confi rming that the CA phase in CAC plays an important role in the delay of PC hydration.     

Performance of the Cement Matrix Composite Material With Rubber Powder

The effect of the deferent rubber content substituted for fine aggregate on the mortar performance was studied. The effects of the rubber coated with the coating materials on the mortar compressive strength, bending strength and impact work were discussed. The optimum rubber powder content and the suitable coating material were found. Throagh the electrical probe test-BEI, SEI and calcium ion distribution, and the slight crack and the interface between the rubber and cement matrix are analyzed. The results show that the rubber powder coated with the surface treatment materials A, B and C has the capability of absorbing a large amount of energy under the compressive and flexural load and the slight cracks of R-C were controlled and restrained.     

Hydration mechanism of sulphoaluminate cement

The feasibility of sulphoaluminate cement (SAC) utilization in support mortar was studied. Setting time and strength of as-received sulphoaluminate cement (SAC) paste were examined, hydration kinetics behavior was determined through Isothermal Calorimeter, and hydration mechanism was investigated by X-Ray diffraction analysis (XRD) and field emission scanning electron microscopy analysis(FSEM). Results showed that as-received SAC contained 61% of anhydrous calcium sulfate (3CA·CaSO4) and dicalcium silicate (C2S). The strength after 1 day or 3 days grew to 68.6% or 85.7% of that after 28 days respectively, while most of hydration heat was released within 1 day. The emergency of three exothermic peaks at acceleration stage was found and hydration kinetics model was established choosing the terminal time of the first exothermic peak at accelerating stage as the beginning of accelerating stage. XRD analysis suggested that large amount of ettringite (AFt) was produced at early age and FSEM observation revealed that ettringite (AFt) formed in sulphoaluminate cement (SAC) paste was characterized of different morphology which was proved to be caused by different ion concentrations.     

微波强化烧成铝酸盐水泥熟料的探讨

用微波技术对铝酸盐水泥熟料进行强化烧成,电炉将铝酸盐水泥生料加热至1000℃～1300℃,然后再用微波炉加热1′5″～4′。熟料的f-CaO测定、XRD图谱以及岩相照片表明,微波大大加快了熟料的烧结反应。Fe2O3对铝酸盐水泥微波强化烧结有促进作用,液相的出现使物料吸波能力有很大提高。     

Hydration mechanism of silica fume-sulphoaluminate cement

Setting time and strength of sulphoaluminate rapid hardening cement （SAC） incorporated in the presence and absence of silica fume （SF） were determined. Combined with the techniques of＂ isothermal calorimeter, XRD and FSEM, the hydration kinetics of the two systems and the effect mechanism of SF on SAC were investigated. The experimental results showed that SF was proved to be beneficial for SAC system, in terms of setting time and late strength gain. Evidence of accelerator effect of silica fume was found during the first 8 hours of hydration. The formation of AFt was accelerated and the microstructure of the hydration products grew denser with incorporation of SF. SF was proved to play the role of dispersion and setting control at early age and had a greater contribution to later strength due to the increment of crystal nucleation point and the pozzolanic activity. Therefore, SF can be used to not only control the hydration kinetics of SAC, but also develop the late strength and improve the microstructure.     

利用低品位石灰石生产低碱水泥的研究与实践

介绍了碱集料反应和国内外碱集料反应对混凝土的破坏情况,在试验基础上,突破传统的水泥配料模式,利用低品位石灰石、砂岩、矾士渣等生产出了高性能低碱水泥。     

Effect of Fine Steel Slag Powder on the Early Hydration Process of Portland Cement

1 IntroductionSteel slag is the waste residue of fluxing mineralsused in the process of steel producing. Its dischargeamount is about 10 % of the production of steel . Steelslag hasn’t been utilized widely and effectively in a longperiod of time[1]. Hundreds of million tons of steel slagare deposited,andthe amount is still increasing withtensof milliontons every year .The deposited steel slag occu-pies great amounts of farmlands and induces serious en-vironment problems . The main chemical c…     

Effect of Microwave Processing on Aiuminate Cement Clinkering

When raw materials we preheated to 1000-1300℃ by electricity and microwave was inputted for 1 min 5 s- 4 rains, then alunminate clinkers were obtained. The f-CaO contents, XRD patterns and lithofacies analysis shiny that the microwave processing accelerutes the clinkering reaction, and Fe2O3 is contributed to the aluminate cement clinkering. The nppeararwe of liquid phase in process of microwave heating increases the microwave absorbability of materials greatly.     

石灰石粉掺量对混凝性能的影响研究

利用石灰石粉外掺法研究不同掺量(0%、5%、10%、15%、20%)的石灰石粉对混凝土和易性以及强度的影响。结果表明,掺入石灰石粉后混凝土的塌落度比基准组变小,但粘聚性和保水性良好;混凝土抗压强度随石灰石粉掺量的增加,呈先增加后减小的趋势,石灰石粉掺量为10%时,其各龄期(7 d、14 d、28 d)抗压强度值最高。