铝酸盐矿物对氯氧镁水泥的影响

本讨论了铝酸盐矿物对氯氧镁水泥的水化产物、耐水性和强度的影响。通过ＸＲＤ相分析，证明了具有水化活性的铝酸盐矿物（如ＣＡ，Ｃ４ＡＦ等）对氯氧镁水泥的水化相有影响；而没有水化活性的铝酸盐矿物（如Ｃ２ＡＳ）对氯氧镁水泥的水化相没有影响。当氯氧镁水泥中ＭｇＯ／ＭｇＣｌ２摩尔比大于５时，含有ＣＡ或Ｃ４ＡＦ的净浆硬化体中主要水化相是３·１·８相，而不含ＣＡ或Ｃ４ＡＦ或含Ｃ２ＡＳ的净浆硬化体中主要水化相是５·     

高水速凝固化材料的性能及其水化硬化机理研究

本文研究了一种新型胶凝材料──以ＣＡＳ水泥熟料为基料的高水速凝固化材料的水化硬化机理和水化产物组成以及水化温度、石膏掺量对其凝结、强度性能的影响。同时还初步探讨了这种材料在土壤固化中的应用。研究结果表明，含Ｃ＿４Ａ＿３Ｓ的ＣＡＳ的水泥熟料浆体与另一种含有石膏、Ｃａ（ＯＨ）＿２、石灰石、悬浮剂和某种碱金属盐的浆体能在较短时间内发生化合作用并形成大量的钙矾石等水化产物，导致该材料在水固比高达２．０～３．０时迅速胶凝、硬化并产生一定的强度；这种材料的石膏掺量有一较佳范围，其性能在环境温度低于３０℃时发挥较佳；同时发现这种材料对含水率很高的泥浆固化效果明显优于Ａｕｇｈｔ—Ｓｅｔ固化剂。     

MgO对C4A3S↑—水化性能的影响

用ＸＲＤ，ＩＲ和化学分析法研究了ＭｇＯ对Ｃ４Ａ３Ｓ↑－晶体水化性能的影响。结果表明，ＭｇＯ的引入不影响Ｃ４Ａ３Ｓ↑－的晶体形态和晶格尺寸，Ｍｇ＾２＋以间隙方式固溶入Ｃ４Ａ３Ｓ↑－晶体的晶格空隙中。用微量热仪和浆体的线性膨胀率探讨了ＭｇＯ对Ｃ４Ａ３Ｓ↑水化性能的影响。结果表明，ＭｇＯ能延缓Ｃ４Ａ３Ｓ↑－的早期水化，降低其线性膨胀率，因而体积稳定性得到提高。     

NaOH和Ca（OH）2对C3A—CaSO4.2H2O—H2O系统早期水化影响的研究

用ＸＲＤ等测试手段，研究了Ｃａ（ＯＨ）２和ＮａＯＨ对Ｃ３Ａ－ＣａＳＯ４．２Ｈ２Ｏ－Ｈ２Ｏ的早期（５～１０ｍｉｎ）水化的影响，实验表明，Ｃ３Ａ和石膏在水中，在饱和及不饱和的Ｃａ（ＯＨ）２溶液，或在〈０．４ｍｏｌ／ＬＮａＯＨ溶液中水化，能迅速形成结晶良好的钙矾石，在这种条件下石膏对Ｃ３Ａ水化并有延缓作用。在有足够固体Ｃａ（ＯＨ）２或Ｃ３Ｓ存在的条件下，或在ＮａＯＨ≥０．４ｍｏｌ／Ｌ的溶液中，石膏和Ｃ３     

CeO2对CaO—MgO—Fe2O3—Al2O3—SiO2系玻璃晶化的影响

本文阐述了制备以ＣｅＯ２为晶核剂的ＣａＯ－ＭｇＯ－Ｆｅ２Ｏ３－Ａｌ２Ｏ３－ＳｉＯ２系微晶玻璃,采用ＳＥＭ,ＸＲＤ和ＤＴＡ等技术,研究了ＣｅＯ２对玻璃成核与晶化的影响,确定了析出的晶相,讨论了加入ＣｅＯ２后玻璃析晶活化能的变化,结果表明,ＣｅＯ２的加入能降低玻璃晶化活化能,促进玻璃相分离使制得的微晶玻璃强度增大,但析出的主晶相仍为钙铁辉石。     

含铬R2O—CaO—Al2O3—SiO2系统结晶质玻璃球状析晶机理的研究

采用顺磁共振（ＥＳＲ）、扫描电镜（ＳＥＭ）、能谱分析（ＥＤＡＸ）、Ｘ射线衍射（ＸＲＤ）等实验方法，研究了Ｃｒ２ＯＥ对Ｒ２Ｏ－ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２系统更上一层楼的晶行为的影响，并对 球状析晶机理进行了分析。球晶是由放射状的针形晶体所构成，尺寸约为几个毫米，且呈均匀分布，主晶相为β－ＣａＳｉＯ３。析晶机理是玻璃中的铬在热处理过程中首先以铬钙尖晶石固熔体「ＣａＣｒ２Ｏｒ」的形式析出，然后β－Ｃａ     

CaO-SiO_2-P_2O_5-H_2O体系中CBC材料的水化产物(二)水化产物的相分析

利用ＳＥＭ－ＥＤＳ和相分析技术对ＣａＯ－ＳｉＯ２－Ｐ２Ｏ５－Ｈ２Ｏ系统中ＣＢＣ材料的水化２８ｄ和３６５ｄ试样的抛光表面进行了观察分析，发现水化初期的物相分布以Ｃａ、Ｓｉ、Ｐ矿相为基体，占总相的６８．０５％；水化后期该相的量减少，Ｃａ、Ｐ相和Ｃａ、Ｓｉ相增多，并出现了纯Ｓｉ相，表明随水化进行，ＳｉＯ２和Ｐ２Ｏ５之间的相互固溶现象减少，最后详细分析了水化反应过程、强度机理以及水化后期体系出现较多ＳｉＯ２的原因     

CaO—Al2O3—SiO2系统玻璃晶化时首析晶相及TiO2的作用机理预测和…

通过ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２系统玻璃的结构分析预测玻璃晶化时首析晶相是钙长石。选取ＣａＯ－Ａｌ２Ｏ３－ＳｉＯ２三元相图成玻璃区内的某点作为基础玻璃的组成，在基础玻璃吕加入ＴｉＯ２。用ＤＴＡ，ＸＲＤ和ＳＥＭ方法的研究结果表明，不玻璃中加ＴｉＯ２与否，晶化时首先析出的晶相都是钙长石，且均为从表面向内部生长，驰预测相符。     

一种新形态钙矾石—管状钙矾石

用扫描电镜、Ｘ射线能谱仪观测和分析了硫铝酸盐水泥系列的水化产物钙矾石的一种特殊显微形貌－管状钙矾石。在水泥净浆试体中、界面上、不同石膏掺量的水泥浆试体、砂浆试体、水化的熟料颗粒中均可观测到管状钙矾石。它的形成可能与非平衡状态生产的熟料中Ｃ４Ａ３Ｓ矿相的某种晶体结构有关。     

TMS—GC法和^31P—NMR及^29Si—NMR法研究CaO—SiO2—P2O5—H2O系统材料的…

探索了ＣａＯ－ＳｉＯ２－Ｐ２Ｏ５－Ｈ２Ｏ系统中的化学结合材料的强度发展情况，其最在劈裂抗拉强度可达３８．２ＭＰａ。用ＴＭＳ－ＧＣ法和＾３１Ｐ－ＮＭＲ及＾２９Ｓｉ－ＮＭＲ法综合研究了这种新型凝材料的水化性能，并将其和β－Ｃ２Ｓ及Ｃ３Ｓ的测试结果进行了比较，发现这种ＣＢＣ材料水化后，出发Ｑ＾３．Ｑ＾４状态的「ＳｉＯ４」聚合体，说明其水化过程及水化机理可能与β－Ｃ２Ｓ及Ｃ３Ｓ的水化这 同，初步认为这是由     

钢渣矿渣基全固废胶凝材料的化学活化

为了促进钢铁冶金渣的高附加值应用,以钢渣、矿渣和脱硫石膏为原料制备胶凝材料,研究了不同掺量CaO或Na2SO4对胶凝材料的化学活化作用,并利用XRD、SEM对掺入激发剂胶凝材料的水化产物进行了分析.结果表明,掺入少量CaO或者 Na2SO4的胶凝材料净浆试块早期抗压强度会有一定的提高,后期强度变化不大;但当Na2SO4掺量超过2%时,净浆试块的抗压强度会降低.掺入激发剂对胶凝材料的水化产物种类不会造成影响,其水化产物主要包括钙矾石(AFt)、水化硅酸钙(C-S-H)凝胶和氢氧化钙(CH).     

氢氧化钙对硫铝酸盐水泥-粉煤灰复合胶凝材料的水化影响

通过凝结时间、抗压强度和电阻率等分析手段,研究了Ca(OH)2对硫铝酸盐水泥-粉煤灰复合胶凝材料水化过程的影响.结果表明,掺入Ca(OH)2明显缩短了硫铝酸盐水泥-粉煤灰复合胶凝材料的凝结时间;当Ca(OH)2掺量为0.5%时,初凝时间最短,1 d、28 d强度均明显提高;当Ca(OH)2的掺量为2%时,28 d强度相比空白样提高了61.9%;掺入Ca(OH)2后,硫铝酸盐水泥-粉煤灰复合胶凝材料的1 d电阻率减小,随着Ca(OH)2掺量增大,电阻率逐渐减小,电阻率变化率极大值提前,说明Ca(OH)2加快了该复合胶凝材料的早期水化进程.XRD分析表明,掺入Ca(OH)2后,水化1 d时钙矾石的生成量增多,消耗无水硫铝酸钙的量增多;水化28 d时钙矾石的生成量相对变化较小,但强度明显增大,粉煤灰对硫铝酸盐水泥强度的贡献较为明显.     

The hydration of 11CaO · 7Al2O3 · CaF2 AT 20°C

Hydration at 20°C of C₁₁A₇ · CaF₂ which exists in regulated set cement was investigated by means of conduction calorimetry, differential thermal analysis, scanning electromicroscopic observation, X-ray diffraction and chemical analysis. The process of hydration and rate of hydration were determined and influence of the various calcium sulfates, calcium hydroxide and carboxylic acid upon the hydration of C₁₁A₇ · CaF₂ was discussed. Mechanism of the strength development was also deduced in relation to the structure of hardened paste.     

磷渣对水泥浆体水化性能和孔结构的影响

通过对水泥浆体凝结性能、水化放热、力学性能和孔结构的测定,以及扫描电镜分析和差热-热重分析,研究了不同掺量磷渣对水泥浆体水化性能和微观结构的影响.结果表明:随着磷渣掺量的增加,浆体的凝结时间延长,水化热减少,早期抗压强度下降.但掺磷渣水泥浆体的后期抗压强度已接近或超过了纯水泥浆体的,磷渣掺量的增加对水泥浆体的后期抗压强度影响不显著.浆体中的Ca(OH)2量随龄期的延长而增加并随磷渣掺量的增加而降低.磷渣的活性效应和填充效应的发挥有效地改善了浆体水化后期的微观结构和孔结构,从而使浆体的力学性能有所提高.     

石膏对贝利特-硫铝酸钡钙水泥强度和硬化浆体结构的影响

研究了石膏对贝利特-硫铝酸钡钙水泥强度和硬化浆体结构的影响.结果表明:贝利特-硫铝酸钡钙水泥熟料的矿物组成主要有C3S、C2S、C,A、C4AF和C2.7B1.25A3S;当水泥中石膏掺量为10%时,贝利特-硫铝酸钡钙水泥的3d、7 d、28 d和90 d抗压强度分别达到了45.0、61.9、82.1和85.6 MPa;贝利特.硫铝酸钡钙水泥的水化产物主要有AFt、Ca(OH)2、C-S-H凝胶等,随石膏掺量的增加,AFt的数量逐渐增加,水化后期的Ca(OH)2数量逐渐减少.用XRD和SEM来分析硬化水泥浆体组成和结构.     

Studies of Early Stages of Paste Hydration of Cement Compounds, II

The paste hydration of mixtures of alite, C₃A, and C₄AF with and without gypsum and/or NaOH was studied by electron-optical and X-ray diffraction techniques. In the absence of both gypsum and NaOH, a foil-like reaction product and hexagonal calcium aluminate hydrates were formed first. Any CO₂, present formed calcium carboaluminate. With time the foils changed to splines of CSH, and hexagonal aluminate hydrates changed to cubic C₃AH₆. When no gypsum was present, NaOH solution retarded the formation of hexagonal aluminates at the very early stages of hydration; it did not have much effect on the later hydration processes. With gypsum but without alkali, a foil-like product and ettringite formed first. Later the foils changed to splines of CSH and ettringite to monosulfate. Alkali, in the presence of gypsum, hastened the formation of splines of CSH. The results suggest that the hydration of alite, even after 14 days, goes through the solution phase.     

Microstructure of cement paste subject to early carbonation curing

Microstructure of Ordinary Portland Cement paste subjected to early age carbonation curing was studied to examine the effect of early carbonation on performance of paste at different ages. The study was intended to understand the mechanism of concrete carbonation at early age through the microstructure development of its cement paste. Early carbonation was carried out after 18-hour initial controlled air curing. The microstructure characterized by XRD, TGA, ²⁹Si NMR and SEM was correlated to strength gain, CO₂ uptake and pH change. It was found that early carbonation could accelerate early strength while allowing subsequent hydration. The short term carbonation created a microstructure with more strength-contributing solids than conventional hydration. Calcium hydroxide was converted to calcium carbonates, and calcium–silicate–hydrate became intermingled with carbonates, generating an amorphous calcium–silicate–hydrocarbonate binding phase. Carbonation modified C–S–H retained its original gel structure. The re-hydration procedure applied after carbonation was essential in increasing late strength and durability.     

碱性和无碱液体速凝剂促凝早强作用机理对比研究

碱性和无碱速凝剂掺入水泥后的水化机理不同,导致应用性能存在明显差异。本文通过测试凝结时间和砂浆抗压强度等宏观性能对比了两种速凝剂的应用性能,并通过水化放热分析、XRD定量分析、热重分析和SEM微观形貌观察等微观方法综合分析了两者的早期水化历程。结果表明:碱性速凝剂加入水泥后,[Al(OH)₄]^-加快了水泥中石膏的消耗速度,水化初期生成大量钙矾石(AFt),促进了硅酸三钙(C₃S)矿物的水化,缩短了水泥浆体的凝结时间并提高了砂浆的早期抗压强度,但石膏的加速消耗也使得单硫型水化硫铝酸钙(AFm)和水化铝酸钙(C-A-H)等水化产物提前生成,影响了水泥基材料的后期抗压强度发展;无碱速凝剂加入水泥后,[Al(OH)₄]^-和SO^2-₄在液相中生成了大量AFt,促进了铝酸三钙(C₃A)和C₃S矿物的水化,影响了氢氧化钙(CH)的结晶析出。值得注意的是,SO^2-₄不仅促进了C₃A生成AFt的过程,也延缓了水泥中石膏的消耗及AFm和C-A-H等产物的生成,因此无碱速凝剂的加入除了明显提高早期抗压强度外,后期28 d抗压强度也不受影响。     

Compressive strength and hydration of wastepaper sludge ash-ground granulated blastfurnace slag blended pastes

Compressive strength and hydration characteristics of wastepaper sludge ash-ground granulated blastfurnace slag (WSA-GGBS) blended pastes were investigated at a water to binder (w/b) ratio of 0.5. The strength results are compared to those of normal Portland cement (PC) paste and relative strengths are reported. Early relative strengths (1 day) of WSA-GGBS pastes were very low but a marked gain in relative strength occurred between 1 and 7 days and this increased further after 28 and 90 days. For the 50% WSA-50% GGBS blended paste, the strength achieved at 90 days was nearly 50% of that of the PC control paste. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric (TG) analysis were carried out to identify the mineral components in the WSA and the hydration products of WSA and WSA-GGBS pastes. The principal crystalline components in the WSA are gehlenite, calcium oxide, bredigite and α′-C₂S (stabilised with Al and Mg) together with small amounts of anorthite and calcium carbonate and traces of calcium hydroxide and quartz. The α′-C₂S and bredigite, which phase separate from liquid phase that forms a glass on cooling, are difficult to distinguish by XRD. The hydration products identified in WSA paste are CH, C₄AH₁₃, C₃A.0.5CC?.0.5CH.H_11.5 and C-S-H gel plus possible evidence of small amounts of C₂ASH₈ and C₃A.3CS?.H₃₂. Based upon the findings, a hydration mechanism is presented, and a model is proposed to explain the observed strength development.     

Hydration and properties of calcium silicate pastes

Microstructures developed in hydrated tricalcium and β-dicalcium silicates paste are related to physical properties of strength, rigidity and shrinkage. Paste microstructure was altered by the use of admixtures and by temperature variations during hydration. Strength, both compressive and tensile, is essentially independent of changes in microstructure and depends primarily on porosity. However, the paste rigidity as estimated from the modulus of elasticity, measured by a new ultrasonic pulse velocity technique, is affected by changes in the CSH material promoted by some admixtures, e.g., calcium chloride. The size of calcium hydroxide crystals may influence total paste shrinkage, although other factors, such as pore size distribution, have not yet been fully assessed.