钢渣水泥性能与水化机理的研究

研究了钢渣水泥的抗硫酸盐侵蚀性，耐磨性，抗碳化性能以及抗干缩变形能力，各项性能指标均达到或超过纯硅酸盐水泥。采用ＸＲＤ，ＳＥＭ，ＤＴＡ，ＩＭＰ等测试手段研究了钢渣水泥的水化产物，孔结构，对其水化机理进行了分析讨论。     

未水化水泥颗粒后期水化对UHPC性能的影响

采用高温加速试验,并结合烧失量法、力学试验、测长法、电通量法、碳化等手段研究了不同养护温度和水胶比条件下未水化水泥颗粒后期水化对UHPC性能的影响。结果表明:60℃水养护能够有效加速UHPC中未水化水泥颗粒的后期水化,试块的结合水量在90d内趋于稳定。随养护龄期的增长,UHPC试块先收缩后膨胀,90d的抗折强度、抗氯离子渗透性和抗碳化性能均下降,抗压强度尚无明显损失。水胶比越低,UHPC试块90d的结合水量增长率越大,膨胀值越大,抗折强度损失率也越高。     

石膏及其种类对水泥水化过程的影响

综述了石膏对波特兰水泥水化过程影响的研究进展，指出了只有系统地研究不同形态的石膏与水泥中各相的相互作用。才有可能全面的揭示石膏在水泥中的作用。不同种类的石膏对水泥水化过程的影响程度不同；高温煅烧石膏能明显提高波特兰水泥的早期强度。     

低水胶比下粉煤灰对水泥早期水化的影响

提出可用等效结合水含量和水化影响因子来定性和定量分析粉煤灰对水泥早期水化作用的大小。若粉煤灰的水化影响因子 >1,则粉煤灰促进水泥水化 ,值越大 ,促进作用越显著 ;若粉煤灰的水化影响因子 <1,则粉煤灰延缓水泥水化 ,值越小 ,延缓作用越显著。同时研究和分析了低水胶比下粉煤灰不同品种和掺量对水泥早期水化的影响     

氯氧镁水泥水化条件对制品性能的影响

本文研究了在一定ＭｇＯ／ＭｇＣｌ２摩尔比条件下，不同拌合水量对氯氧镁水泥水化相的结晶形态及数量和制品性能的影响。     

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。     

中间相C3A对硅酸盐水泥水化的影响

在现有理论基础上,探讨了中间相Ｃ３Ａ对硅酸盐水泥水化反应历程的影响,认为Ｃ３Ａ矿物与硅酸盐矿物水化产物ＣＨ反应仅是中间过程,其反应前后未改革浆体中的ＣＨ浓度,提出了Ｃ３Ａ吸收高浓度处的ＣＨ,经反应将其输到ＣＨ浓度较低的Ｃ３Ａ水化产物周界中,通过在原质下的吸收放出的“囊泵”作用促进硅酸盐水泥水化,该作用是非显著的物理作用,而非化学作用。     

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-...     

Influence of Calcium Sulfate State and Fineness of Cement on Hydration of Portland Cements Using Electrical Measurement

1 IntroductionThe calcium sulfate state includes gypsum, hemi-hydrate and anhydrite .Inthe modern Portland cement in-dustry,the gypsumis used as a setting retarder for reac-tion with C3A[1]. With the presence of gypsumin theformof CaSO4·2H2O,the gypsum dissolves and reactsprimarily with C3A and C4AF to form ettringite . Thisettringite isinitiallyformed with a veryfine-needle crystalstructure ,whichforms a diffusion barrier onthe surface ofthe cement . This coating avoids the unwanted fl…     

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.     

Influence of ultra-fine fly ash on hydration shrinkage of cement paste

1INTRODUCTION Hydrationshrinkageisalsoknownaschemicalshrinkage[1].Thesolidvolumeincreasesafterce menthydrating,buttheabsolutevolumeofcementwatersystemreduces.Usuallythetotalamountofvolumeshrinkageofcementwatersystemis7%9%[1,2].Withthedevelopmentofthetechno logyofcementandconcrete,concretewithhighstrengthandhighperformanceisthedevelopingtendencynow.However,nowadays,comparedwithordinaryconcrete,thehydrationshrinkageofhighperformancecementconcreteincreasesobvi ouslybecauseoftheaccelerationof…     

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…     

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。     

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.     

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.     

Effects of citric acid on hydration process and mechanical properties of thermal decomposed magnesium oxychloride cement

In order to make full use of salt lake magnesium resources and improve the strength of the thermal decomposed magnesium oxychloride cement(TDMOC), the effects of citric acid on the hydration process and mechanical properties of TDMOC was studied. The hydration heat release at initial 24 h and strengths at 3, 7, and 28 days of TDMOC specimens were conducted. The hydration products and paste microstructure were analyzed by XRD, FT-IR and SEM, respectively. The results showed that citric acid can not only reduce the 24 h hydration heat release and delay the occurring time of second peak of TDMOC, but also produce more 5Mg(OH)2·MgCl 2·8H2O and less Mg(OH)2 in hydration process of TDMOC. More perfect and slender crystals were observed in the microstructure of the TDMOC pastes with citric acid. The results demonstrated that citric acid as an additive of TDMOC can decrease the hydration heat release and increase the compressive strength and flexural strength of TDMOC. The possible mechanism for the strength enhancement was discussed.     

NMR research on cement clinker and its structures in early age hydration

Clinker has long been regarded as a critical factor for cement hydration and solidification.α-C2S and β-C2S in 2CaO·SiO2(C2S) phase and C3S Monoclinic 1(C3S M1) and C3S Monoclinic 3 (C3S M3) in 3CaO·SiO2 (C3S) phase were clearly recorded in the 29Si MAS NMR spectra.The content of C3S phase in the clinker deduced from the fine peak analysis coincides with the phase quantification analysis calculated by the Taylor-Bogue method based on XRF,which also accords to the statistical data in industrial production.NM...