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磷石膏胶凝材料的生产 总被引:8,自引:0,他引:8
介绍多种生产磷石膏胶凝材料的工艺路线。提出我国磷石膏胶凝材料应以生产α半水石膏为宜。研究工作的重点应努力提高工艺的技术经济指标,以增强其与天然石膏的竞争力。 相似文献
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特种化纤可有效阻止磷石膏基胶凝材料(PGS)开裂,并通过不同龄期样品的抗冲击功、抗折强度、抗压强度、空隙率和受压样品外貌及断口形貌分析等表征增韧、补强和耐水的效果。结果表明:化纤可显著对PGS增韧补强和改善耐水性。在20℃(湿度大于90%)、化纤掺量为0.3%时,PGS固化体28 d的抗压强度、抗折强度和抗冲击功分别为45.1 MPa、8.9 MPa和1145 J/m2,软化系数和吸水率分别为0.81和9.1%;PGS固化体160 d总孔隙率(20.03%)较28 d的降低了5.1%,PGS固化体160 d密度(1.59 g/cm3)较28 d提高了0.6%;特种化纤穿插于硬化体内部,具有桥联搭接作用。 相似文献
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研究了外加剂对磷石膏基复合胶凝材料性能的影响.通过单因素实验考察了外加剂CaCl2 (CC)、Na2SO4(NS)、NaF(NF)和水玻璃(NSO)的不同掺量对复合胶凝材料性能的影响,通过正交试验得到了外加剂复配的最佳方案,即有CC为0.6%,NS为0.2%,NSO为0.6%,NF为0.3%.正交优化组的3d和28 d的抗压强度为35.96MPa、42.88 MPa,其强度分别提高了19.27%和20.89%.采用XRD和SEM等方法分析了复合胶凝材料的水化产物组成和微观形貌.分析结果表明外加剂不仅能加快磷石膏基复合胶凝材料的水化反应进程,还可以生成更多更致密的水化产物,使其结构更加紧密,提高了复合胶凝材料的力学性能. 相似文献
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磷石膏基胶凝材料在使用时,工作性能较差,需要加入减水剂来改善工作性。而磷石膏胶凝材料对现有的混凝土减水剂的存在适应性不良的问题。为了深入了解减水剂对磷石膏基胶凝材料的匹配性,本文探究了萘系、聚羧酸和脂肪族类三种减水剂及掺量对磷石膏基砂浆材料各项性能的影响规律。通过对砂浆浆体的流动度、硬化体的力学性能,以及28d吸水率和软化系数进行评价,获得最佳的减水剂种类和掺量。研究结果表明:萘系减水剂与磷石膏基砂浆的适应性较好,且掺量为0.4%时较合适;砂浆流动度为17.0 cm,砂浆硬化体的7 d、28 d和90 d抗压强度分别为18.1 MPa、33.1 MPa和37.6 MPa,28 d吸水率和软化系数分别为2.51%和0.91。 相似文献
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以未经处理的原状磷石膏制备磷石膏基复合胶凝材料,测试磷石膏基复合胶凝材料的力学性能,考察生石灰的掺量、水灰比以及成型压力对磷石膏基复合胶凝材料力学性能的影响。结果表明:当生石灰掺量为4%时,磷石膏-矿渣复合胶凝材料具有较好的力学性能,矿渣微粉对磷石膏-粉煤灰复合胶凝材料的力学性能有增强作用。对于磷石膏-矿渣-炉渣复合胶凝材料,当成型压力超过3 MPa时,制备的材料力学性能明显下降。同浇注成型试样相比较,在5 MPa成型压力下的压实成型试样,材料孔隙率提高,特别对于200 nm以上孔所占体积分数来说,其所占体积分数要远远高于浇注成型试样,导致了材料微观结构劣化,力学性能变差。 相似文献
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磷石膏基水硬性胶凝材料是近几年发展起来的一种以磷化工业副产物磷石膏为主要原料的新型建筑材料。与传统硅酸盐和矿渣水泥相比,磷石膏无活性不能直接作为胶凝材料,使用前必须对其进行改性。针对目前磷石膏基胶凝材料凝结时间长、早期强度低等缺点,研究了材料组成配比及外加剂对凝结时间和早期强度的影响,获得了磷石膏基胶凝材料的改性方法。当矿渣粉(KF)和硅基纳米粉末(WS)质量比为3∶17,水玻璃(NS)、富铝盐(NA)和高效聚羧酸减水剂(JS)的质量分数分别为0.3%、0.7%和0.3%时,可将其初凝时间控制在130~260 min、终凝时间控制在280~600 min;胶砂早期抗折强度3 d达3.5 MPa以上、7 d达5 MPa以上;早期抗压强度3 d达20 MPa以上、7 d达35 MPa以上。改性后的磷石膏基胶凝材料可替代25%~40%及以上普通硅酸盐水泥应用于建筑材料领域。 相似文献
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利用半水磷石膏(HPG)协同灰钙粉和水泥固化原状磷石膏(RPG)制备磷石膏基复合胶凝材料(PBCM)。采用单因素实验探究了HPG掺量对PBCM浆体性能的影响,并通过正交实验进一步探究各掺合料对PBCM强度及耐水性的影响。结果表明:HPG可作为RPG的固化材料,既高效又环保,掺量在20%(质量分数,下同)以上的HPG可彻底解决PBCM浆体的泌水问题,显著缩短浆体凝结时间,掺量在40%以上的HPG可有效改善浆体流动性;HPG、灰钙粉和水泥可有效提高PBCM强度,其中水泥对耐水性影响显著。微观形貌分析显示,PBCM的主要水化物二水硫酸钙和钙矾石晶体交织生长于RPG晶体之间,从而实现了对RPG的有效固化。 相似文献
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磷肥工业废弃物磷石膏和冶金工业废弃物富镁镍渣每年的排放量较大,由于二者具有胶凝活性较低和安定性差等缺点,导致其利用率较低。本文将原状磷石膏和富镁镍渣协同利用制备胶凝材料,研究了磷石膏-富镁镍渣基胶凝材料基础性能。通过对浆体的流动度、硬化体的力学性能,以及28 d吸水率和软化系数进行评价,为原状磷石膏和富镁镍渣协同综合利用提供实验支持。研究结果表明:磷石膏-富镁镍渣胶凝材料硬化体抗压强度28 d强度可达31.7 MPa,且耐水性好吸水率为2.46%,软化系数为0.91。将制得的磷石膏-富镁镍渣基胶凝材料硬化体与32.5普通硅酸盐水泥进行对比,性能相接近。 相似文献
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利用磷石膏和磷渣可配制出性能优良的矿山充填料,提高矿山资源的综合利用率,防止山体崩塌开裂,同时综合利用了工业废渣,减轻环境污染。充填料浆体的浓度对工作性和强度有显著影响,适当的料浆浓度既能保证浆体具有足够的自流性能,同时其强度发展也较为理想;磷渣在激发剂的作用下逐步水化硬化,与磷石膏构成一个结晶结构体,其强度随着磷渣掺量的增加而提高。浆体的自流性能可简化充填工艺,降低充填成本。 相似文献
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为制备大掺量磷石膏基复合胶凝材料,在确定主要水化产物类型的基础上,通过计算临界钙矾石膨胀破坏的边界条件,确定各组分最佳掺量范围,研究其对复合胶凝材料力学性能、干缩性能的影响,并通过X射线衍射(XRD)、扫描电镜(SEM)等测试方法研究水化产物的组成及发展规律。研究结果表明:通过理论配料计算,矿粉掺量为50%(质量分数)时,最大磷石膏掺量为26.3%(质量分数),最小熟料掺量为23.6%(质量分数)。最佳配比组28 d胶砂抗压强度为45.2 MPa,线膨胀率小于0.04%;对比组28 d抗压强度仅有36.4 MPa,线膨胀率远大于0.04%。XRD、SEM表征结果表明,磷石膏基复合胶凝材料的水化产物主要是钙矾石(AFt)和水化硅酸钙(C-S-H)凝胶,氢氧化钙几乎反应完全;对比组钙矾石生成量远大于最佳配料组,微观结构存在大量裂缝。这说明理论配料计算可以有效用于磷石膏基复合胶凝材料的配比优化。 相似文献
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Chloride diffusion in partially saturated cementitious material 总被引:2,自引:0,他引:2
Erik P Nielsen 《Cement and Concrete Research》2003,33(1):133-138
The paper proposes a combined application of composite theory and Powers' model for microstructural development for the estimation of the diffusion coefficient as a function of the moisture content of a defect-free cementitious material. Measurements of chloride diffusion in mortar samples (440 kg/m3 rapid-hardening Portland cement, w/c=0.5, maturity minimum 6 months) stored at 65% and 85% RH, as well as in vacuum-saturated mortar samples, illustrate the applicability of the method. 相似文献
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A new kind of alkali-slag-red mud cementitious material, abbreviated as ASRC, with both high early and ultimate strength and excellent resistance against chemical attacks has been developed by the application of composite solid alkali activator into slag-red mud mixture system. The hydration products of this cement at ambient temperature have been investigated by means of XRD, IR, TG-DTA, TEM, EDXA, etc. The results showed that the hardened cement paste was mostly consisted of C-S-H gel, being very low in Ca/Si ratio, very fine in size and extremely irregular in its shape. Neither Ca(OH)2 and AFt, which are usually present in the hardened Portland cement paste, nor zeolite-like products have been detected. These characteristics are considered to be the chemical reasons for the high early and ultimate strength and good resistance against chemical attacks of the hardened ASRC cement paste. 相似文献
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Innovation in use and research on cementitious material 总被引:2,自引:0,他引:2
In this paper we discuss innovations in concrete technology which are currently being applied in the field—namely high and ultra high performance (strength), and self consolidating concrete. We discuss the factors which have enabled these developments and ongoing needs in these areas. The importance of sustainability as the major driver for future innovations and prospects for development of new cementitious materials with lower environmental impact is briefly discussed. Finally the importance of innovation in research is examined. The dramatic development in experimental and computational techniques over recent years opens up wide-ranging possibilities for understanding the micro- and nano- scale chemical and physical processes which underlie performance at a macroscopic level. The example of computational approaches at the atomic and molecular scale is presented in detail. In order to exploit the opportunities presented by such new techniques, there needs to be greater efforts to structure interdisciplinary, multi-group research. 相似文献
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《Journal of the European Ceramic Society》2020,40(14):4909-4922
In this work, we have described the fabrication and characterization of novel cement containing hardystonite (HT; Ca2ZnSi2O7) as a bioactive phase which was mixed with brushite (B; CaHPO4. 2H2O) calcium phosphate and citrate liquid as setting solution. Effect of various citrate concentration in hardening solutions consisting of the mixture of citric acid and trisodium citrate dihydrate were used to study the phase transformations, mechanical properties, microstructural changes and in vitro cytotoxicity of cements. The results showed that while the HT phase revelead slow hydration ability, the brushite was gradualy hydrolyzed with increasing concentration of citrates in liquid. The mechanical strength increased in wet and dry state as the concentration of the citrates increased, with the highest values observed in the citrate_8 % cement. The in vitro cytotoxicity testing of cement extracts revealed high viabilities of osteoblasts in citrate_1 % and citrate_4 % but a moderate extract cytotoxicity was verified in citrate_8 % cement. 相似文献