粉煤灰改性无水石膏胶结材的研究

以脱硫石膏与粉煤灰两种工业废渣为主要原料制得的粉煤灰无水石膏胶结材（以下简称ＦＡＢ），具有比石膏制品高的强度与耐水性。本文对该胶结材的配制原理与方法，养护方式及材料性能进行了研究。初步分析了该胶结材水化硬化特点，结构及其与性能的关系。     

在不同条件养护的氟石膏粉煤灰胶结材的水化硬化性能

研究了在不同条件养护的氟石膏粉煤灰胶结材的水化硬化过程及对其力学性能的影响. 室温空气中养护试样的主要水化产物是二水石膏和CSH凝胶. 试样脱模后在60 ℃蒸养6 h将阻碍无水石膏向二水石膏转化,但促进粉煤灰的火山灰反应,此时主要水化产物是CSH凝胶;继续水养护进一步促进胶结材的水化,除生成较多CSH凝胶外,还有部分钙矾石生成. 氟石膏粉煤灰胶结材凝结慢,早期强度低,但后期强度持续增长至较高程度. 由于水硬性水化产物包裹石膏晶体,形成致密浆体结构,使氟石膏粉煤灰胶结材具有优良的耐水性.     

二水磷石膏粉煤灰复合胶结材研究

二水磷石膏粉煤灰复合胶结材 (PGF)是直接将未经处理的磷石膏通过加入粉煤灰和激发剂改性制得的新型胶结材。本文介绍胶结材的适宜配比、养护方式与制度、性能等 ,通过XRD、SEM微观分析 ,结合水化热、pH值、孔结构测定及宏观力学性能测试 ,对PGF适宜的碱激发、强度发展与养护、耐水性改善的原因等进行了分析与讨论     

有不同条件养护的氯石膏粉煤灰胶结材的水化硬化性能

研究了在不同条件养护的氯石膏粉煤灰胶结材的水化硬化过程及对其力学性能的影响。室温空气中养护试样的主要水化产物是二水石训和ＳＣＨ凝胶。试样脱模后在６０℃蒸养６ｈ将阻碍无水石膏向二水石膏转化，但促进粉煤灰的火山灰反应，此时主要水化产物是ＣＳＨ凝胶；继续水养护进一步促进胶结材的水化，除生成较多ＣＳＨ凝胶外，还有部分钙矾石生成。氟石膏粉煤灰胶结材凝结慢，早期强度低不同但后期强度持续增多至较高程度。由于水硬     

脱硫石膏粉煤灰胶结材水化硬化机理及耐水性研究

以火电厂的两种废渣即脱硫石膏和粉煤灰为主要原料制得的胶结材，其强度明显高于普通石膏制品，软化系数大于０．８５。采用水化热测定、ＸＲＤ和ｐＨ值测定及ＳＥＭ／ＥＤＸＡ分析，并结合宏观试验结果，分析了这种胶结材的水化硬化机理和微结构特点，并对其耐水性提高的原因进行了讨论。     

石膏-粉煤灰基复合材料性能研究

本文研究了膨胀珍珠岩、短切维尼纶纤维、水泥熟料对石膏-粉煤灰基胶凝材料抗折、抗压、软化系数和表观密度的影响.结果表明, 半水石膏-粉煤灰胶结材硬化体的强度随着粉煤灰掺量的增加而降低;添加水泥熟料作为粉煤灰的激发剂,可使石膏-粉煤灰复合材料的耐水性能提高;以珍珠岩作为轻骨料的复合材料,随着珍珠岩质量分数的增加,对复合材料的力学性能影响不是很大,复合材料的密度大大减小;短切维尼纶纤维对复合材料的对抗压强度贡献不大,只可以增强制品的抗折强度.     

粒度分布对磷石膏-石灰-粉煤灰胶结材物理性能的影响

针对磷石膏-石灰-粉煤灰体系胶结材大量利用磷石膏时,强度发展以及耐水性能的缺陷,采用机械粉磨以改善其粒度分布。探究了不同粒度分布对磷石膏-石灰-粉煤灰体系胶结材的物理性能和耐水性的影响。将磷石膏样品与生石灰以及粉煤灰按一定比例混合,陈化24h再通过粉磨不同时间,达到不同的粒度分布。将不同粒度的样品外掺5%水泥,3%AC增强剂以及0.5%聚羧酸减水剂,按照标准稠度用水量加水在160 mm×40 mm×40 mm试模中成型,在养护室中养护到规定龄期再测定试件的物理性能以及微观分析。结果表明,磷石膏掺量达到40%,通过粉磨的物理活化,该体系按照水泥砂浆砌块成型,28 d抗压强度≥27.76 MPa,软化系数达到86%的胶凝材料,并且无废水排除,杜绝二次污染。     

发展循环经济,利用电厂粉煤灰、脱硫石膏生产水泥

本文研究了利用粉煤灰作水泥混合材、脱硫石膏作水泥缓凝剂的水泥性能以及脱硫石膏的作用机理。研究表明，粉煤灰作为活性混合材、脱硫石膏作为缓凝剂，水泥凝结时间正常，并且对水泥的力学性能和安定性有积极作用，可以作为水泥生产的部分原料。     

磷石膏、粉煤灰胶结材的研究

利用生石灰中和磷石膏中的可溶性磷,既消除了可溶性磷的危害,为中材提供了CaO,同时可在大降低低胶结材生产中的能耗,胶结材可用于制建筑抹砂浆等,强度和耐性良好,工艺过程用磷石膏直接生产半水石膏后再生石膏制品简单经济。     

石膏对粉煤灰活性激发的研究进展

用石膏来激发粉煤灰的活性,可广泛用于粉煤灰胶结材料中,更易制成价廉质轻的环保型产品.同时也叙述了其激发硬化机理.     

Properties of a ternary calcium sulfoaluminate–calcium sulfate–fly ash cement

In this paper, cement combinations based on calcium sulfoaluminate cement (CSAC) were developed and the effect of fly ash and the hemihydrate form of calcium sulfate on the properties of the systems was studied. Fly ash (FA), anhydrite (ANH), flue-gas desulfurization gypsum (FGDG) and plaster gypsum (PL) were used to develop appropriate CSAC/calcium sulfate and CSAC/calcium sulfate/addition systems, the hydration of which was studied. Tested properties of cements were the compressive strength and the setting times. The results suggest that the use of fly ash in the presence of anhydrite accelerates the formation of a strong ettringite-rich matrix that firmly accommodated unreacted fly ash particles, both synergistically contributing to a dense microstructure. At a given sulfate content, the use of anhydrite was shown to be favourable in terms of the setting times, heat patterns and strength development compared to the hemihydrate-based formulations.     

公路粉煤灰水泥的研制（一）

文中研究了熟料掺量、复合激发剂、石膏掺量、水泥颗粒粒度对公路粉煤灰水泥的影响.获得了公路粉煤灰水泥的最佳配料方案和工艺参数.与粉煤灰硅酸盐水泥性能相比,公路粉煤灰水泥早期强度略低于粉煤灰硅酸盐水泥,凝结时间较长,但其7d～28d水化龄期内的强度增长率较高,28d强度已赶上或超过粉煤灰硅酸盐水泥,胶砂流动度好.     

Influence of fly ash fineness on strength, drying shrinkage and sulfate resistance of blended cement mortar

In this paper, the influence of fineness of fly ash on water demand and some of the properties of hardened mortar are examined. In addition to the original fly ash (OFA), five different fineness values of fly ash were obtained by sieving and by using an air separator. Two sieves, Nos. 200 and 325, were used to obtain two lots of graded fine fly ash. For the classification using air separator, the OFA was separated into fine, medium and coarse portions. The fly ash dosage of 40% by weight of binder was used throughout the experiment. From the tests, it was found that the compressive strength of mortar depended on the fineness of fly ash. The strength of mortar containing fine fly ash was better than that of OFA mortar at all ages with the very fine fly ash giving the highest strength. The use of all fly ashes resulted in significant improvement in drying shrinkage with the coarse fly ash showing the least improvement owing primarily to the high water to binder ratio (W/B) of the mix. Significant improvement of resistance to sulfate expansion was obtained for all fineness values except for the coarse fly ash where greater expansion was observed. The resistance to sulfuric acid attack was also improved with the incorporation of all fly ashes. In this case the coarse fly ash gave the best performance with the lowest rate of the weight loss owing probably to the better bonding of the coarse fly ash particles to the cement matrix and less hydration products. It is suggested that the fine fly ash is more reactive and its use resulted in a denser cement matrix and better mechanical properties of mortar.     

粉煤灰资源综合利用现状研究

粉煤灰是火力发电厂中煤粉燃烧后产生的固体颗粒,我国每年因燃煤产生的粉煤灰约6亿t,占世界粉煤灰总产量的一半。针对粉煤灰露天堆积造成的环境污染和资源浪费问题,综述了其资源综合利用现状,结果表明,粉煤灰主要应用于建筑、化工、环保、农业、造纸、陶瓷等领域,实现了粉煤灰的高值化利用。今后应增强创新意识,加大科研投入,注重产品的改造和开发,借鉴发达国家的成功经验,探索粉煤灰综合利用新方法和新工艺,努力提升其资源利用率。     

Mechanical behaviour of various mortars made by combined fly ash and limestone in Moroccan Portland cement

Physico-chemical properties and mechanical behaviour of ternary cements made by Portland cement, fly ash and limestone are studied. The mixtures at various compositions of clinker, gypsum fly ash and limestone are intimately ground and compared to other compositions without fly ash. Blended fly ash cements are also studied. The results show that fly ash acts as grinding agent by reducing the required time to obtain the same percentage of particles retained on a 80-μm sieve as the standard cement. Fly ash cements lead to an important extension of setting time than limestone cements. The replacement of clinker by limestone gives better mechanical strengths than the mixtures containing fly ash at early days; after 28 days, the cements prepared by incorporation of fly ash gain an important strength. From mechanical point of view, an optima dosage was obtained at 77% clinker, 2% gypsum, 7.5% fly ash and 13% limestone composition.     

Properties of lightweight expanded polystyrene aggregate concretes containing fly ash

Lightweight concretes can be produced by replacing the normal aggregates in concrete or mortar either partially or fully, depending upon the requirements of density and strength levels. The present study covers the use of expanded polystyrene (EPS) beads as lightweight aggregate, both in concrete and mortar. The main aim of this programme is to study the mechanical properties of EPS concretes containing fly ash and compare the results with these in literature on concretes containing OPC alone as the binder. The effects of EPS aggregate on the green and hardened state characteristics of concretes containing fly ash were evaluated. The compressive strength of the EPS concretes containing fly ash show a continuous gain even up to 90 days, unlike that reported for OPC in literature. It was also found that the failure of these concretes both in compression and split tension was gradual as was observed earlier for the concretes containing plastic shredded aggregates. The stress-strain relations and the corresponding elastic modulus were also investigated.     

Finding the optimum binder for fly ash pelletization

The present work investigated various binders to assist the fly ash particles' coagulation within the intermediate sintering temperature zone. In order to find the appropriate binding agents for fly ash pelletization, some common materials were examined with focus on the compressive strength. The main experimental variables were heat treatment temperature and the binder/fly ash proportions. As a result of the close investigation, alkali and acidic materials such as sodium hydroxide, potassium hydroxide and phosphoric acid were found quite acceptable based on the strength and cost effectiveness. A few organic materials also acted as desirable binders, but they revealed a few critical limitations when used in aqueous solution and at hot fluid environment. Inorganic binders, such as cement and lime, showed excellent cost effectiveness, but seemed to be disadvantageous for the high temperature process.     

我国粉煤灰利用研究的进展

评述了近几年来粉煤灰基础研究的有关进展，介绍了粉煤灰在高性能混凝土（ＨＰＣ）、新型胶凝材料、建筑制品方面的应用及粉煤灰的特殊用途，在此基础上，提出了今后利用粉煤灰的意见     

分光光度法快速测定粉煤灰水泥中粉煤灰含量

通过分光光度法,对粉煤灰水泥中Fe2O3和SO3总含量进行检测,后分别检测粉煤灰、熟料、脱硫石膏中的Fe2O3和SO3含量,最后通过混合材掺量计算公式,计算粉煤灰水泥中的粉煤灰含量。该检测方法准确性较高,并且检测快捷方便,检测结果绝对误差范围小于5%。