Effect of superplasticizers on the early age hydration of sulfoaluminate cement

The effects of two types of superplasticizers on the properties of CSA cement pastes during early hydration were studied. The influences of two types of superplasticizers on the properties of cement pastes, including the normal consistency, setting time, fl uidity, and compressive strength, were investigated by using various methods. The hydration products of the cement pastes cured for 1 day and 3 days were studied by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results show that the PCE type superplasticizer retards the early age hydration while the FDN type superplasticizer accelerates the early age hydration of the CSA cement. Both types of superplasticizers have no infl uence on the further hydration of CSA cement, confi rmed by the calorimeter tests as well. The ultrasonic pulse velocity measurements were used to probe the influence of two types of superplasticizers on the hydration of CSA cement pastes at a high water-cement ratio（0.45）. The results show that the PCE type superplasticizer retards the early age hydration of the CSA cement while the FDN type superplasticizer has little infl uence on the early age hydration of the CSA cement.     

煤矸石代黏土煅烧水泥熟料配方优化试验研究

为获得煤矸石代黏土配料应用于水泥生产的煅烧热工条件和合理配方,选取不同煤矸石和不同品位的石灰石等原料配制6种水泥生料,在实验室熟料煅烧试验台中进行不同温度下煅烧水泥熟料的试验研究,对试验所得的熟料样品分别进行了游离CaO质量分数的测定和矿物组成的X射线衍射（XRD）分析.试验结果表明：煤矸石代黏土与中钙石灰石和高中钙石灰石配料,都能烧制出合格的水泥熟料,烧成温度比黏土配料的烧成温度降低50 ℃以上;而煤矸石与高钙石灰石的配方则在烧成温度上没有明显优势,说明煤矸石与中钙石灰石或高中钙石灰石配料更能烧制出高质量的水泥熟料.     

水泥熟料配方及煅烧工艺探讨

选择易烧性较好的原燃料，适当提高水泥熟料中的n值，降低KH值，增加有效硅酸盐矿物成份（C3S＋C2S）的总量，从而提高了熟料的实物质量。     

利用波面水泥熟料冷却器回收能量

对波面水泥熟料冷却器的设计参数和经济指标进行了评价 ,论证了它用于能量回收的可行性 ,为水泥熟料冷却能量的回收提供了一条途径     

利用波面水泥熟料冷却器回收能量

对波面水泥熟料冷却器的设计参数和经济指标进行了评价,论证了它用于能量回收的可行性,为水泥熟料冷却能量的回收提供了一条途径。     

硅酸盐水泥熟料的光学显微结构特征的研究

利用反光显微镜观察了不同煅烧制度下硅酸盐水泥熟料的显微结构特征，讨论煅烧温度和时间对水泥熟料显微结构的影响，运用此方法可初步了解生产过程中出现的种种问题，为指导水泥熟料的生产和质量监控提供可靠依据。     

添加剂对水泥性能与水化过程的影响

研究了单组分添加剂及其复合添加剂对水泥物理性能和水化特性的影响,结果表明：单组分添加剂对水泥的细度、净浆流动性、胶砂强度均有一定提高,复合添加剂的助磨、减水、增强效果均有大幅度提高,水泥80μm筛余降低45.8%,勃氏比表面积增加了14.0%,粒径为3-30μm的颗粒明显增多.水泥粉体的SEM分析表明：添加复合添加剂能显著降低粗颗粒的比例;水泥净浆流动度由135 mm提高到了190 mm;3 d、28 d强度提高了3.2MPa和7.4MPa.水泥水化样XRD分析表明：掺入复合添加剂能提高水泥的水化速率,促进水化产物的生成.     

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…     

Prediction of free lime content in cement clinker based on RBF neural network

Considering the fact that free calcium oxide content is an important parameter to evaluate the quality of cement clinker, it is very significant to predict the change of free calcium oxide content through adjusting the parameters of processing technique. In fact, the making process of cement clinker is very complex. Therefore, it is very difficult to describe this relationship using the conventional mathematical methods. Using several models, i e, linear regression model, nonlinear regression model, Back Propagation neural network model, and Radial Basis Function (RBF) neural network model, we investigated the possibility to predict the free calcium oxide content according to selected parameters of the production process. The results indicate that RBF neural network model can predict the free lime content with the highest precision (1.3%) among all the models.     

金属尾矿代黏土配料煅烧水泥熟料试验研究

为获取金属尾矿代黏土配料用于水泥熟料生产的工艺参数以及分析金属尾矿对不同品位石灰石的适应性，选取6种金属尾矿，在实验室高温炉不同温度下进行尾矿代黏土配中、高钙石灰石煅烧水泥熟料的试验研究.对试验所得熟料样品分别进行了游离氧化钙质量分数的测定和矿物组成X射线衍射（XRD）分析.试验结果表明，金属尾矿代黏土与中钙、高钙石灰石配料均能烧制出合格熟料；熟料的烧成温度较黏土配料1 450 ℃的烧成温度降低了100～150 ℃；当金属尾矿配中钙石灰石时在1 300 ℃即可完成熟料烧成，与金属尾矿配高钙石灰石时1 350 ℃的煅烧温度相比，金属尾矿配中钙石灰石更适合水泥熟料烧成.     

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.     

掺矿粉水泥的水化机理研究

研究利用在硅酸盐水泥中掺加矿粉来提高水泥的抗折强度,降低脆性,并通过ＴＧ－ＤＴＡ、Ｘ－衍射及ＳＥＭ等微观分析方法对掺矿粉水泥的水化机理进行研究,结果表明,矿粉的掺入不权可以提高水泥的水化程度,增加水泥石的密实度,同时也可以降低水泥石的脆性。     

Quantitative XRD Analysis of Cement Clinker by the Multiphase Rietveld Method

1　IntroductionPhasesincementclinkerhavebeenquantifiedbyBouge ,microscopeorXRDmethods .TheBougemethodisareconstructionofthechemicalanalysis ,basedonanequilibriumsystem ,whilemicroscopecountingistediousandtime -consuming .Aldridgegaveasummaryofthestatusoftheaccuracyandprecisionofphasequantifica tioninPortlandcementbytheabovethreebasictech niques .HepointedouttheXRDmethodhasagreaterpo tentialforanindustriallaboratorythantheBougeormi croscopemethods[1] .However,theXRDmethoddidnotgivesatisfa…     

用电解锰渣制备高铁硫铝酸盐水泥熟料

以湘潭电化集团“两矿法”生产电解二氧化锰排放的电解锰渣（EMR）为原料,采用X射线荧光光谱分析（XRF）、扫描电子显微镜一能谱仪（SEM—EDS）、X射线衍射（XRD）、热重分析（TG）等检测手段对其化学组成、形貌特征、物相结构及物化性质进行了分析．结果表明,电解锰渣是一种富含Si、S、Fe、Ca、Al的材料,可以用作烧制高铁硫铝酸盐水泥（FAC）熟料的原材料．分别考察了煅烧温度、保温时间、电解锰渣掺量对高铁硫铝酸盐水泥抗压强度的影响,当煅烧温度1200℃、保温时间60min、电解锰渣掺量25％左右时为煅烧工艺的最优条件,3d抗压强度最高可达49．8MPa．研究结果可为电解锰渣的资源化利用提供新的途径和方向．     

混凝土中水泥水化反应放热模型及其应用

大体积混凝土结构水化热温度场分析的关键是混凝土中水泥水化反应放热模型的确定。基于化学反应动力学原理，提出了一种物理意义明确，考虑了温度和化学反应物浓度对化学反应速率影响的混凝土中水泥水化反应放热模型，并将其应用于有限元分析。算例分析表明，该模型能很好地拟合了混凝土绝热温升的实测数据，较精确地预测了在不同浇筑温度下混凝土绝热温升的变化规律。     

Influence of cellulose ethers on hydration products of portland cement

Cellulose ethers are widely used to mortar formulations,and it is significant to understand the interaction between cellulose ethers and cement pastes.FT-IR spectra,thermal analysis and SEM are used to investigate hydration products in the cement pastes modified by HEMC and HPMC in this article.The results show that the hydration products in modified cement pastes were finally identical with those in the unmodified cement paste,but the major hydration products,such as CH(calcium hydroxide),ettringite and C-...     

Composition Design for High C3S Cement Clinker and Its Mineral Formation

A new composition of Portland cement clinker was studied, in which KH, SM and IM was 0.98,2.4 and 2.4 respectively as well as its meal added 1%CuO （in mass）. Fired at 1 200℃,1 350℃,1 400℃ and 1 450℃ for 30 min, the resultant mineral phases component and mineral morphology were analyzed. The performances of the cement which was made of clinker burned at 1 450℃ and fly ash were determined. By means of QXRD, XRD and optical microscopy, it is shown that the clinker burnt at 1 450℃ has the larger size crystals and distinct crystal interface, in which the C3S content is 73.37% and the mineral phases is dominantly C3S, following by minor C2S, C3A and tetracalcium aluminoferrite. The results reveal that a new type of high C3S content clinker can completely be made by traditional temperature-time schedule. The performances of the cement produced from this clinker with addtion of 50% fly ash and 5% gupsum were in agreement with the 32.5 strength grade of Portland fly-ash cement. The results also show that the clinker has a significant effect of saving energy and utilizing waste slag.     

WHⅡ型超缓凝剂对硅酸盐水泥水化过程的影响

研究了WHⅡ型超缓凝剂对硅酸盐水泥水化、水化热、凝结时间、强度等的影响,运用XRD以及SEM对硅酸盐水泥的水化过程进行跟踪测试,结果表明适量使用WHⅡ型超缓凝剂可以得到合适的缓凝效果和增强作用。     

硅酸盐水泥水化动力学简化模型

为了更加清晰地阐明水灰比对硅酸盐水泥水化进程的影响,分析了硅酸盐水泥的水化动力学模型(Tomosawa模型,T模型),并将其简化为由传质过程、相界面反应和扩散过程所组成的简化T模型．结合化学结合水法测定水化程度,应用T模型及简化T模型对两种不同水灰比水泥浆体的水化动力学进行研究．结果表明:水泥水化动力学模型中的参数受水灰比的影响各异,其中与传质过程相关的参数几乎不受水灰比的影响;与相界面反应相关的参数受水灰比的影响较小;而与扩散系数相关的参数受水灰比影响显著．简化T模型可以较好地分段模拟水化速率随水化程度变化的总体趋势,且该趋势不受水灰比影响,但是相界面反应控制向扩散过程控制转变时的临界水化程度受到水灰比的影响,且随水灰比增加,临界水化程度增大．     

葡萄糖酸钠与高效减水剂复合使用对水泥水化历程的影响

用直接测温法及X射线衍射技术,系统研究了葡萄糖酸钠与萘系、氨基磺酸盐系及聚羧酸盐系3种高效减水剂复合使用对水泥水化热、水化温峰、温峰出现时间及不同水化龄期Ca(OH)2和钙矾石(AFt)生成量等方面的影响.结果表明:与糖钙和三聚磷酸钠相比,葡萄糖酸钠及其与高效减水剂复合对水泥水化历程的影响规律明显不同.单掺葡萄糖酸钠使水泥水化第2放热峰出现时间延迟,但温峰值及水化热与空白样基本持平,温峰时的Ca(OH)2生成量增大.复合使用葡萄糖酸钠与高效减水剂时,与不同品种高效减水剂复合使用对水泥水化历程的影响不同.