粉煤灰基地质聚合物材料性能研究

采用3种不同成分的粉煤灰在碱激发剂的作用下制备地质聚合物,研究了粉煤灰成分对地质聚合物抗压强度的影响,采用SEM和XRD对样品进行表征.结果表明,粉煤灰中Al含量高时,地质聚合物初期强度增长较快;Si含量高时,后期强度增长较快;Ca含量高时,样品中出现C-S-H胶体,它们对材料的强度有一定贡献.     

粉煤灰基土壤聚合物微观结构分析

使用粉煤灰和碱激发剂制备粉煤灰基土壤聚合物,并采用X射线衍射分析、扫描电镜-能谱分析和红外光谱分析等技术手段分析其微观结构,明确微观结构本质及其反应前后的结构变化。粉煤灰基土壤聚合物的主要产物有:八面沸石、水霞石和无定形产物,产物中均含有碱金属,化学成分不同于水泥水化产物。因粉煤灰玻璃体表面保护层结构致密,有些粉煤灰颗粒没有完全反应,存在没有反应掉的外壳。在碱激发溶液的作用下,[AlO4]四面体可能取代Si-O-Si链上部分[SiO4]四面体。     

基于强度指标的粉煤灰基地质聚合物设计

以粉煤灰为主要原材料,少量的硅灰为SiO2调节材料,以水玻璃和NaOH溶液作激发剂,制备了粉煤灰基地质聚合物材料,探讨了影响粉煤灰基地质聚合物强度的主要因素,结果表明:养护温度对地质聚合物强度影响最大,NaOH溶液摩尔浓度次之,NaOH溶液与水玻璃的质量比影响最小。     

粉煤灰基土壤聚合物混凝土性能试验研究

使用粉煤灰和碱激发剂制备粉煤灰基土壤聚合物混凝土,并系统研究其物理力学性能、干缩和耐久性能。粉煤灰基土壤聚合物混凝土早期强度相对较低,后期增长明显。粉煤灰基土壤聚合物砂浆的干缩主要发生在早期,14d龄期后的干缩率均显著小于普通水泥砂浆,在150d龄期时为普通水泥砂浆的71.8%。硫酸盐侵蚀试验表明:在3%硫酸钠溶液中,粉煤灰基土壤聚合物砂浆没有产生任何膨胀,具有优良的抗硫酸盐侵蚀性能。即使粉煤灰基土壤聚合物含碱量高达10.6%,也不会产生危害性的碱-硅酸反应。粉煤灰基土壤聚合物混凝土快速碳化28d的碳化深度为14.0mm,抗冻等级在F100以上。自然浸泡法试验表明:粉煤灰基土壤聚合物混凝土的水溶性氯离子有效扩散系数为1.79×10-12m2/s,是混凝土的30.5%,具有比普通混凝土更好的抗氯离子侵蚀性能。粉煤灰基土壤聚合物混凝土具有适用的物理力学性能,较低的干缩,优良的耐久性能,是一种新型的结构材料。     

粉煤灰基地聚合物修补材料的组成设计与性能

以粉煤灰、矿粉两种工业废料为主要原材料,模数为1.2~1.8的水玻璃作为激发剂制备地聚合物。采用五因素四水平的正交试验组成设计方案,测试了水胶比(W)、碱激发剂掺量(S)、矿粉取代率(B)和水玻璃模数(M)在不同水平下试样的流动度、凝结时间、抗压强度和拉伸粘结强度。通过对结果进行极差分析和因素指标分析,得出这种绿色环保型修补材料的组成设计与性能指标之间的关联。综合分析得出,当水胶比为0.28,碱激发剂掺量为0.14,矿粉取代率为0.4,水玻璃模数为1.2时,制备出的地聚合物性能良好,达到绿色环保型建筑修补材料的要求。     

粉煤灰地聚物的力学性能及其化学分析

通过实验对粉煤灰地聚物的力学性能及水化产物成分进行了研究,得出了最佳制备工艺参数,并利用FTIR和DTA/TG表征手段对不同龄期粉煤灰地聚物的凝胶体作了分析,表明在水化过程中粉煤灰内玻璃体发生了解聚—缩聚反应,主要形成N-A-S-H产物。     

粉煤灰/黄土基陶瓷膜支撑体的制备

针对无机陶瓷膜支撑体制备成本高及粉煤灰污染环境的问题,以粉煤灰和黄土为原料,以羧甲基纤维素(carboxymethyl cellulose,CMC)为粘结剂,以木屑为造孔剂,采用滚压法和固态粒子烧结法制得低成本支撑体,并通过X射线衍射仪(X-ray diffractometer,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、压汞法、三点弯曲法及自制纯水通量测定装置分析了支撑体的物相组成、微观形貌、孔隙率及孔径分布、抗折强度及纯水通量,探究了原料配比、CMC及木屑添加量对支撑体性能的影响。结果表明,当粉煤灰与黄土配比为3∶2、CMC添加量为4%、木屑添加量为1%时,制得支撑体性能最佳,更有利于陶瓷膜的工业化生产,产品的纯水通量为37 516.69 L/(m~2·h),抗折强度为11.28 MPa,孔隙率为26.23%,平均孔径为5.11μm。     

Concrete retrofitting using metakaolin geopolymer mortars and CFRP

This paper presents results about the use of metakaolin based geopolymers mortars for retrofitting purposes. Two main situations are addressed, the use of geopolymeric mortars as a repairing layer or as a binding agent to insure the adhesion between CFRP sheets and the concrete substrate. Several compositions of metakaolin geopolymer mortars were executed by varying the percentage of sand/binder mass ratio and the concentration of sodium hydroxide. It was found that metakaolin geopolymer mortars show a high mechanical resistance and a relevant adhesion to the concrete substrate. Although their adhesion strength is lower than the one present by commercial pre-pack repair mortars, they are very cost-effective (5–10 times less expensive). On the other hand, the adhesion strength between CFRP and geopolymer mortars proved to be lower than expected which could be due to the fact that the composition of the geopolymeric mortars was not optimized and also to the fact that the CFRP used was not prone to this kind of application.     

粉煤灰PRC材料的制备

PRC(PoreReducedCement)是一种高性能水泥材料 ,它在工艺、性能、用途等方面有许多特有的优点 ,本文利用粉煤灰作为材料的组成部分 ,测试其力学性能。研究表明粉煤灰的最佳掺量为 3 0 % ,粉煤灰PRC材料的微观结构显示 ,粉煤灰在PRC材料体系中主要是微集料作用     

粉煤灰矿渣建筑胶结料的研制

在以粉煤灰为主的胶结料中掺入适量的矿渣能大幅度提高其强度,矿渣掺量以控制在15%￣25%为宜;石灰对粉煤灰和矿渣都起激发剂的作用,在本试验范围内,石灰适宜掺量为15%￣25%;粉磨细度与强度成正比关系,综合考虑产量、质量与电耗的关系,胶结料的比表面积控制在420￣450m2/kg。以粉煤灰、矿渣、石灰和石膏配置的胶结料,后期强度能大幅增长,凝结时间可调,抗大气稳定性较好。若采用蒸养技术,可得到3d抗压强度达45MPa以上,后期抗压强度能继续增长的硅酸盐制品。     

粉煤灰复合矿物外加剂的研制

本文利用化学活化和物理活化相结合的原理 ,研制出一种复合型混凝土矿物外加剂 ,通过有效激发粉煤灰的活性 ,利用粉煤灰可以作为胶结材的性质 ,取代部分水泥 ,在满足使用要求的基础上大幅度降低水泥用量。     

脱硫石膏/粉煤灰抹面材料的制备与研究

以脱硫石膏和粉煤灰作为基料,添加适宜的缓凝剂、保水剂及其他助剂,制备出脱硫石膏/粉煤灰抹面材料。通过研究不同粉煤灰掺量、缓凝剂和保水剂对脱硫石膏/粉煤灰抹面材料性能的影响,确定出脱硫石膏/粉煤灰抹面材料的配比组成,基料中脱硫石膏:粉煤灰=4:1,复合缓凝剂A和保水剂甲基纤维素的掺量分别为0.2%和0.2%。     

粉煤灰基轻质泡沫材料的制备与性能研究

以粉煤灰为原料,通过造孔剂发泡法和浆料发泡法制备了新型轻质泡沫材料,确定了其最佳制备工艺条件.考察了浆料发泡法制备过程中碱激发和泡沫掺量对泡沫材料结构和性能的影响,通过调节泡沫掺量和坯体烧结温度,材料的显气孔率、密度、吸水率、抗压强度分别达到62.74％、0.50 g/cm3、126.50％、6.76 MPa.     

Lime based steam autoclaved fly ash bricks

About 10 million tonnes of fly ash are produced yearly as waste from coal fired thermal power plants in Turkey. Only a small portion of this waste is utilized as a raw material in the production of cement and concrete. In this study, Seyitömer power plant fly ash was investigated in the production of light weight bricks. Fly ash, sand and hydrated lime mixtures were steam autoclaved under different test conditions to produce brick samples. An optimum raw material composition was found to be a mixture of 68% fly ash, 20% sand and 12% hydrated lime. The optimum brick forming pressure was 20 MPa. The optimum autoclaving time and autoclaving pressure were found 6 h and 1.5 MPa, respectively. The compressive strength, unit volume weight, water absorption and thermal conductivity of the fly ash–sand–lime bricks obtained under optimum test conditions are 10.25 MPa, 1.14 g/cm³, 40.5% and 0.34 W  m⁻¹ K⁻¹ respectively. The results of this study suggested that it was possible to produce good quality light weight bricks from the fly ash of Seyitömer power plant.     

粉煤灰超高强高性能混凝土配制

采用比表面积为１４０００ｃｍ２／ｇ的超细磨粉煤灰和高效减水剂配制出坍落度２４３ｍｍ,２８ｄ抗压强度１０８．５５ＭＰａ,１８０ｄ抗压强度１４０．４ＭＰａ的超高强高性能混凝土。对用原状粉煤灰、硅灰、超细磨粉煤灰分别作混凝土的掺合料进行了性能对比,指出超细磨粉煤灰既有粉煤灰本身的“滚珠轴承”润滑作用和火山灰反应增强作用,又有硅灰的填隙挤水和密实增强作用。     

高掺量粉煤灰泡沫玻璃的制备

以粉煤灰和废玻璃为主要原料，辅以适宜的外加剂，用烧结法制备了粉煤灰掺量高达40％。体积密度低达155．1kg／m^3的粉煤灰泡沫玻璃。对影响粉煤灰泡沫玻璃质量的工艺因素进行了分析讨论。     

灰坝磨细灰与其他粉煤灰的性能对比研究

通过试验研究,比较灰坝磨细灰与分选灰及磨细灰的性能差异,期望为灰坝灰作为混凝土掺合料提供技术参考.粉磨过程降低灰坝磨细灰的平均粒径,增加细颗粒含量,但由于粉磨不均匀导致细度过大;由于本身结构及粉磨过程的破坏,灰坝磨细灰及磨细灰的球状颗粒少、不规则形态多;掺灰坝磨细灰的水泥标准稠度最大,凝结时间最短,胶砂强度最低;灰坝磨细灰作为混凝土掺合料,可降低工程造价减少环境污染,但需提高粉磨工艺,控制掺量,并适当增加单位用水量,进而提高混凝土的强度及耐久性.     

大力开展资源综合利用生产高质量粉煤灰制品--西北地区产量最大的蒸压粉煤灰砖生产线介绍

详细介绍了西北地区产量最大的蒸压粉煤灰砖生产线的特点：①设计思维创新--立体工厂节约土地;②技术创新--实现蒸压釜自动化开关门;③增设预养室,节汽节能。     

蒸压粉煤灰砖专用砌筑砂浆的配制及性能研究

通过正交试验优化外加剂配比,配制了一种柔韧性好、自收缩小的蒸压粉煤灰砖专用砌筑砂浆,研究了该砂浆与蒸压粉煤灰砖的粘结性能和砌体抗剪切性能。结果表明,Ⅱ级粉煤灰等量取代25%的水泥,纤维素醚、5010N型可再分散醋酸乙烯酯-乙烯共聚胶粉和萘系高效减水剂掺量分别为0.1%、2%和0.6%,胶砂比1∶5的专用砌筑砂浆与蒸压粉煤灰砖的28 d粘结强度和砌体抗剪切强度分别为0.58 MPa和0.51 MPa,明显高于普通砂浆(粘结强度0.28 MPa、抗剪切强度0.14 MPa),可满足表面较光滑、易干燥收缩的蒸压粉煤灰砖砌筑的要求。     

Resistance to acid degradation,sorptivity, and setting time of geopolymer mortars

Experimental evaluations were conducted to determine the water sorptivity, setting time, and resistance to a highly acidic environment, of mortar with alkali-activated ground granulated blast furnace slag (GBS) binder and also of combinations of fly ash and GBS binders. Binders were activated using mixtures of NaOH and Na₂SiO₃ solutions. The molarity of NaOH in the mixtures ranged from 10 mol·L⁻¹ to 16 mol·L⁻¹, and the Na₂SiO₃/NaOH ratio was varied from 1.5 to 2.5. Mortar samples were produced using three binder combinations: 1) GBS as the only binder; 2) blended binder with a slag-to-fly ash ratio of 3:1; and 3) mixed binder with 1:1 ratio of slag to fly ash. Mortar samples were mixed and cured at (22 ± 2) °C till the day of the test. The impact of activator solution alkalinity, activator ratio Na₂SiO₃/NaOH, GBS content on the rate of water absorption were evaluated. After 7, 28, and 90 d of immersion in a 10% sulfuric acid solution, the resistance of a geopolymer matrix to degradation was assessed by measuring the change in sample weight. The influence of solution alkalinity and relative fly ash content on setting times was investigated. Alkali-activated mortar with a slag-to-fly ash ratio of 3:1 had the least sorptivity compared to the two other binder combinations, at each curing age, and for mortars made with each of the NaOH alkaline activator concentrations. Mortar sorptivity decreased with age and sodium hydroxide concentrations, suggesting the production of geopolymerization products. No reduction in weight of sample occurred after immersion in the strong acid H₂SO₄ solution for three months, regardless of binder combination. This was due to the synthesis of hydration and geopolymerization products in the presence of curing water, which outweighed the degradation of the geopolymer matrix caused by sulfuric acid.