共查询到20条相似文献,搜索用时 234 毫秒
1.
系统研究了I级粉煤灰、III级粉煤灰和等外粉煤灰对混凝土抗压强度和自收缩的影响,并采用纳米划痕仪重点分析了不同品质粉煤灰混凝土的微观力学性能.结果表明:III级粉煤灰和等外粉煤灰均明显降低混凝土的早期和后期抗压强度,且随着掺量的增加而下降,而I级粉煤灰能明显提高混凝土的后期强度,且随着掺量的增加而增加.I级粉煤灰、III级粉煤灰和等外粉煤灰均能明显降低混凝土的自收缩,且等外粉煤灰降低效果最好.在微观力学性能方面,I级粉煤灰与水泥基体界面区结构显著优于III级粉煤灰和等外粉煤灰,且界面区微观力学性能明显高于III级粉煤灰和等外粉煤灰. 相似文献
2.
3.
4.
5.
在混凝土中掺加粉煤灰(Fly ash)替代部分水泥可以显著降低W/B,并同时获得良好的工作性,而且粉煤灰混凝土的后期强度发展良好。研究分析了普通水泥、普通粉煤灰和磨细再生粉煤灰(p-Fly ash)制备的C30和C50混凝土工作性和强度。结果表明:相同W/B时,在C30和C50混凝土中普通粉煤灰混凝土的坍落度最大,流动性优于磨细再生粉煤灰混凝土和普通水泥混凝土;普通水泥混凝土的早期强度高于普通粉煤灰混凝土和磨细再生粉煤灰混凝土;普通水泥混凝土后期强度低于普通粉煤灰混凝土和磨细粉煤灰混凝土;磨细粉煤灰活性高于普通粉煤灰,相同配合比时磨细再生粉煤灰混凝土的强度要高于普通粉煤灰混凝土。 相似文献
6.
7.
粉煤灰综合利用现状及发展建议 总被引:16,自引:1,他引:16
介绍了粉煤灰的几种主要综合利用途径:粉煤灰制备建筑材料,包括粉煤灰制砖、制各种砌块、制取水泥和混凝土基本材料等;粉煤灰在农业方面可以制成肥料和土壤改良剂;粉煤灰在废水处理和烟气脱硫方面的应用等。应加深对粉煤灰综合利用的认识,加快研究成果产业化步伐。 相似文献
8.
9.
粉煤灰及其制品在屋面保温层中的种类有原状粉煤灰保温层、粉煤灰膨胀珍珠岩保温层、粉煤灰加气混凝土保温层、加气混凝土碎块保温层等,本文将简述这几种作法的特点和施工要点,最后作一简要的评述对比。 1 原状粉煤灰保温层 1.1 作法和特点原状粉煤灰保温层是目前造价最低、利用粉煤灰量大的保温层,其保温效果不低于水泥蛭石和水泥白灰炉渣,施工方法简便易行。 相似文献
10.
结合笔者近期对粉煤灰的研究工作,综述了粉煤灰的综合利用现状和发展趋势,主要包括在建筑材料、土力工程、农业、功能材料等方面的应用,可为提高粉煤灰利用率、降低环境污染提供依据;并介绍了增加粉煤灰再生材料附加值和提高粉煤灰市场价值的途径,以期进一步促进粉煤灰的回收利用。 相似文献
11.
12.
13.
14.
15.
16.
This work aims to study the effect of substitution of fly ash for homra on the hydration properties of composite cement pastes. The composite cements are composed of constant proportion of OPC (80%) with variable amounts of fly ash and homra. The addition of fly ash accelerates the initial and final sitting time, whereas the free lime and combined water contents decrease with fly ash content. The fly ash acts as nucleation sites which may accelerate the rate of formation of hydration products which fill some of the pores of the cement pastes. The fire resistance of composite cement pastes was evaluated after firing at 250, 450, 600, 800 °C with rate of firing 5 °C/min with soaking time for 2 h. The physico-mechanical properties such as bulk density and compressive strength were determined at each firing temperature. Moreover, the phase composition, free lime and microstructure for some selected samples were investigated. It can be concluded that the pozzolanic cement with 20 wt% fly ash can be used as fire resisting cement. 相似文献
17.
18.
19.
In this paper the mineralogy and geochemistry of Greek and Chinese coal fly ash are examined. Annual production of fly ash in China is around 160 Mt while in Greece lignite fly ash accounts around 10 Mt. Even though the mineralogical and chemical composition of the fly ashes coming from these two countries differs, there are common questions on the utilization of this material. The variation of the Greek fly ash’ chemical composition, from Ca-poor to Ca-rich fly ash, has resulted to applications such as dam construction, use in cement and possibly in concrete and road construction. The Chinese fly ash, which is rich in mullite, is broadly applied for brick making. 相似文献
20.
表面固化防尘技术在贮灰场的工程应用 总被引:1,自引:0,他引:1
针对我国燃煤电厂贮灰场普遍存在的二次扬尘问题,开发出HG系列灰场表面固化防尘剂,并已应用于工程实践,应用结果表明:该技术具有防尘效果好,治理见效快,成本低廉,施工工艺简单灵活等特点 相似文献