环保型套筒灌浆料的配合比设计及性能研究

选用碱矿渣水泥作为胶凝材料,结合Dinger-Funk方程的最紧密堆积理论,用粉煤灰漂珠作为矿物掺合料,并用铜尾矿砂部分取代天然砂来提高粉体的堆积密度,制备套筒灌浆料.研究了塑性膨胀剂掺量、粉煤灰漂珠掺量、铜尾矿掺量、砂胶比对套筒灌浆料性能的影响,并对最紧密堆积设计配合比进行了验证.结果表明:随着塑性膨胀剂掺量的增加,...     

磨细粉煤灰对水泥基复合胶凝材料流变性能及硬化性能的影响

本文主要研究磨细粉煤灰对水泥基复合胶凝材料的流变性能及硬化性能的影响.研究结果表明:磨细粉煤灰较小的颗粒能够弥补水泥粉体颗粒中8μm以下较小颗粒的缺乏,使磨细粉煤灰-水泥复合胶凝颗粒形成良好的级配,在掺量适宜的情况下对复合水泥浆体的流动度会略有改善,但掺量过大,会显著降低复合水泥浆体的流动度;与Ⅰ级粉煤灰相比,磨细粉煤灰的颗粒粒径更小,火山灰活性更大,火山灰活性对强度的贡献在3d时开始显现,且随着龄期增长越来越大,能显著提高硬化浆体中后期抗压强度;与抗压强度相比,磨细粉煤灰更利于提高抗折强度,且掺量越大,中后期抗折强度越高.     

中国干混砂浆的应用研究概况

从干混砂浆的性能、组分以及聚合物干粉对其性能影响和作用机理等方面论述了干混砂浆在中国的研究进展.中国国内目前关于干混砂浆的理论研究主要集中在聚合物共混改性水泥砂浆,无机矿物外加剂和聚合物种类、成分、掺量等对水泥砂浆性能影响方面. 干混砂浆所用聚合物种类和掺量对干混砂浆的各种性能影响显著.对聚合物的作用机理研究几乎还是空白.     

水泥-粉煤灰-脱硫石膏干混抹面砂浆制备及变形性能

以粉煤灰(FA)及脱硫石膏(FGD)取代部分水泥,制备了水泥-粉煤灰-脱硫石膏干混抹面砂浆,并对胶凝材料体系进行了试验优选.在材料制备基础上,对优选砂浆进行了力学性能、和易性及体积变形性能测试.结果表明,优选的三组干混砂浆力学性能分别满足M7.5、M10的强度要求;新拌砂浆的流动性、保水性满足规范要求,其中粉煤灰掺量越大,流动性越好;硬化砂浆表现出较好的"收缩补偿"效应,且脱硫石膏掺量越大,减缩效应越明显,28 d干缩率最大仅为110×10-6;圆环法加速开裂试验表明,优选出的砂浆具有较低的开裂敏感性,水泥掺量不超过15%时,砂浆28 d均未见肉眼可见裂纹.综合试验结果,推荐干混砂浆配比为:水泥:粉煤灰:脱硫石膏:砂=0.15:0.60:0.25:3.     

废弃混凝土制备干混砌筑砂浆的试验研究

利用废弃混凝土生产制备再生细骨料和再生粉体,并应用于干混砌筑砂浆中,通过调整用水量控制砂浆的稠度在70mm~80mm,以此研究再生粉体掺量及胶砂比对干混砌筑砂浆基本性能、力学性能以及抗冻性能的影响。研究结果表明,干混砌筑砂浆的基本性能与再生粉体掺量及胶砂比的变化均呈线性关系;当胶砂比为1:3,再生粉体掺量为10%时,其28d抗压强度可达35.0MPa,比未掺加再生粉体时仅减小8.1%,且砂浆的抗冻性能符合规范要求。     

材料组成对砂浆基本需水率及堆积密实度影响

以石粉掺量、粉煤灰掺量、砂级配、体积砂率为自变量，设计四因素四水平正交试验，对砂浆基本需水率、堆积密实度进行了测试。使用极差分析、方差分析法对测试结果进行分析，确定了各因素对砂浆基本需水率、堆积密实度影响程度的大小排序为粉煤灰掺量>砂级配>体积砂率>石粉掺量。采用层次分析法进行了配合比优化，得出了考虑基本需水率、堆积密实度两指标下的最佳配比，即石粉掺量10%+粉煤灰掺量60%+细度模数3.4+体积砂率42%。     

煤气化渣玻化微珠制备保温砂浆

利用煤气化渣合成的玻化微珠(VM-CGS)作为保温骨料制备保温砂浆,研究了VM-CGS粒径和掺量、粉煤灰替代水泥量以及憎水剂添加量对保温砂浆性能的影响.实验结果表明,VM-CGS是一种内部呈蜂窝状骨架结构,以闭孔为主的轻质保温骨料.由3～5mm粒径的VM-CGS制备的保温砂浆性能最优.VM-CGS掺量增加虽然可以降低样品导热系数,但样品的其他性能会随之减弱.粉煤灰替代10％(质量分数)的水泥可以提高保温砂浆整体性能,憎水剂掺量达到水泥质量0.8％以后才能实现有效憎水.利用VM-CGS可制备出满足GB/T 20473-2006《建筑保温砂浆》的Ⅰ型保温砂浆.     

超硫酸盐水泥实际与最密集堆积的灰色关联度与抗压强度的关系

本文采用激光粒度分析仪测试超硫酸盐水泥粉体粒径,用以反映超硫酸盐水泥的粒径分布;采用机械压力法制备的超硫酸盐水泥干粉压实体,其空隙率可以宏观上反映颗粒间的物理堆积密实度;根据Dinger-Funk数学模型得出粉体最佳颗粒群分布即最紧密堆积颗粒群分布;运用灰色关联分析原理考察粉体实际颗粒群分布与最紧密堆积颗粒群分布的相关性;基于以上分析建立水泥净浆抗压强度与超硫酸盐水泥堆积效应的关系.试验结果表明:超硫酸盐水泥粉体实际颗粒群分布与最紧密堆积颗粒群分布的相关性越高,压实体空隙率越低,抗压强度越高.     

胶凝材料颗粒组成对混凝土抗裂性能的影响

混凝土抗裂性能与其胶凝材料的堆积紧密程度有关。运用不同颗粒组成的水泥或粉煤灰调整胶凝材料的颗粒级配,可以拓宽颗粒分布范围,适当增加粗颗粒含量,提高混凝土抗裂性。用粉煤灰充当胶凝材料中的粗颗粒,不仅能改善混凝土抗裂性能,而且后期强度增进率较高,有利于提高耐久性;水泥企业应重视水泥颗粒级配的合理性,水泥中保持一定量的粗颗粒非常必要。试验表明,增加40μm以上颗粒含量就能起到改善混凝土抗裂性能的作用。     

FMI增强剂在粉煤灰砂浆中的研究与应用

研究了FMI增强剂对粉煤灰砂浆强度、分层度、容重、抗冻性能的影响. 试验证明,FMI增强剂掺入能明显提高粉煤灰的掺量, 有效改善粉煤灰砂浆的力学性能和耐久性能, 得出了FMI增强剂在粉煤灰砂浆中的适宜掺量.     

Packing effect and pozzolanic reaction of fly ash in mortar

This research is to study the effect of particle size of fly ash on packing effect and pozzolanic reaction of mortar when 20% of fly ash is used to replace Portland cement type I. Both effects can be determined by using fly ash and insoluble material which have almost the same particle size to replace Portland cement type I. Normally, the compressive strength of fly ash mortar is contributed from hydration reaction, packing effect, and pozzolanic reaction. For mortar mixed with insoluble material, the compressive strength is due to hydration reaction and packing effect. Thus, compressive strength due to pozzolanic reaction can be determined from the difference in compressive strength between fly ash mortar and insoluble material mortar. The results show that the strength activity index of fly ash mortar depends on the median particle size of fly ash and curing ages of mortar samples. At early ages, the strength activity index of fly ash mortar due to packing effect is higher than that due to pozzolanic reaction. At the ages of 3 to 90 days, the difference in strength activity index due to packing effect of fly ashes with median particle size of 2.7 and 160 μm is almost constant about 22% of the strength of standard mortar (STD). The differences in strength activity index due to pozzolanic reaction of fly ashes with median particle size of 2.7 and 160 μm are 3%, 20%, and 27%, respectively, at the ages of 3, 28, and 90 days.     

生物质灰对水泥硬化浆体抗压强度影响的试验研究

对比研究了生物质灰与普通粉煤灰在粒度分布、颗粒形态、化学组成、活性指数等方面的不同,并开展了不同掺量生物质灰对水泥硬化浆体抗压强度的影响研究.结果表明:生物质灰颗粒形状不规则、平均粒径及粒径分布范围较大,具有特有的细长纤维状颗粒,且其活性组分Al2O3不足普通粉煤灰的三分之一;生物质灰的火山灰活性小于普通粉煤灰;相同掺量下,生物质灰-水泥复合胶砂各龄期的抗压强度均小于普通粉煤灰-水泥复合胶砂,生物质灰掺量越大,复合胶砂的强度相比纯水泥组下降程度越大;与普通粉煤灰相比,掺加生物质灰的硬化水泥浆体微观结构更为疏松多孔,特别是其特有的细长纤维状颗粒的存在.     

粉煤灰-矿渣微粉复合双掺对水泥砂浆抗酸雨侵蚀性能的影响

研究了粉煤灰、矿渣微粉复合双掺时对水泥砂浆的强度以及抗模拟酸雨侵蚀性能的影响。通过试验发现:随着粉煤灰、矿渣微粉总掺量的不断增加,砂浆强度逐渐下降;各不同配比的砂浆经pH值为4.0的模拟酸雨干湿交替循环腐蚀后的强度变化规律为先升高后下降;与纯水泥砂浆试件相比,如粉煤灰、矿渣微粉的掺入过高,则会降低试件的强度值,但是如以强度增长率来评价砂浆的抗酸雨侵蚀能力,则各不同比例的粉煤灰、矿渣微粉复合双掺等量取代水泥配制的砂浆的强度增长率均优于同等条件下纯水泥砂浆试件,即粉煤灰、矿渣微粉复合双掺对水泥砂浆试件在模拟酸雨条件下的强度发展有改善作用。     

石灰石粉和粉煤灰对复合胶凝材料性能的影响

研究了石灰石粉和粉煤灰对复合胶凝材料性能的影响。试验结果表明,石灰石粉具有比粉煤灰更好的减水效应;在石灰石粉-粉煤灰-水泥三元复合胶凝材料中,石灰石粉和粉煤灰掺量相同时,其复合胶凝材料的早期强度比粉煤灰高,而后期更低,但两者复合时,强度仍更高。     

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.     

熟料和粉煤灰的颗粒尺寸分布与水泥性能的灰色关联分析

将不同比表面积的熟料和粉煤灰分别混合制得不同比表面积的粉煤灰水泥,分别测定粉煤灰水泥胶砂强度和熟料、粉煤灰的颗粒尺寸分布.运用灰色系统原理分别就熟料和粉煤灰的颗粒尺寸分布对水泥强度的影响进行数学分析.研究表明:熟料颗粒粒径在0～30 μm为正关联,>30 μm为负关联,其中10～20 μm颗粒对水泥强度的影响最大;粉煤灰颗粒粒径在0～40 μm为正关联,且其活性较高,>40 μm颗粒为负关联,其活性没有得到充分发挥.     

Characteristics and pozzolanic reactivity of glass powders

This paper deals with the morphology, fineness and pozzolanic activity of four glass powders: one (GP-fine) from the screening of crushed waste glasses, one (GP-dust) from a dust collector for the glass crushing process and two (GP-4000 and GP-6000) from further grinding of the powder from the dust collector in a ball mill. GP-fine and GP-dust consist mainly of large flaky particles, while GP-4000 and GP-6000 consist mainly of small angular particles. The finenesses of these glass powders are measured by particle size distribution and Blaine fineness method. For a similar particle size distribution, ground glass powder has a higher Blaine specific surface area than Portland cement due to the angular morphology of glass particles. Finely ground glass powders exhibited very high pozzolanic activity. The finer the glass powder is, the higher its pozzolanic reactivity is. An increase in curing temperature accelerates the activation of pozzolanic reactivity of both glass powder and coal fly ash in terms of strength development rate. Mortar cube strength results (ASTM C109) indicated that curing temperature has a greater influence on the glass powder than on fly ash. The rapid mortar bar expansion test (ASTM C1260) results indicate that the replacement of Portland cement with ground glass powder also reduces the expansion due to alkali-aggregate reactions, although it is not as effective as coal fly ash.     

矿物掺合料细度对水泥胶砂力学性能的火山灰效应

通过分析单掺矿粉、单掺不同磨细程度的粉煤灰及复掺粉煤灰和矿粉的胶砂早期强度的变化规律,得出粉煤灰的磨细程度及粉煤灰与矿粉的复掺比例会影响胶砂的早期强度。粉煤灰越细,越有利于提高胶砂早期强度,复合掺合料之间各成分的最佳配合比可以充分发挥各自的活性,从而提高胶砂早期力学性能。     

分选与磨细粉煤灰对水泥胶砂性能的影响

研究了分选与磨细粉煤灰的颗粒分布与形貌的差异及对水泥胶砂性能的影响。研究结果表明:当勃氏比表面积相近,磨细粉煤灰的中位粒径大于分选细粉煤灰,其圆珠状颗粒较少,表面较为粗糙。在相同水胶比的条件下,掺分选粗粉煤灰的水泥胶砂流动度及强度均低;分选粗粉煤灰磨细后,不仅减少了颗粒的粘连,增加了比表面积,而且提高了粉煤灰的反应活性和水泥胶砂流动度及强度,虽其水泥胶砂流动度仍小于掺分选细粉煤灰的水泥,3d水泥胶砂强度也略低,但其28d水泥胶砂强度略高于掺分选细粉煤灰的水泥;在相同水泥胶砂流动度的条件下,掺磨细粉煤灰配制的水泥胶砂3d强度低于掺分选细粉煤灰的水泥,但随着水化龄期的增长,其差距逐步缩小,至60d时可超过后者。     

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.