夏热冬冷地区不同新型墙体材料试验研究

以安徽省两淮矿区固体废弃物粉煤灰和煤矸石制备的烧结煤矸石空心砖、粉煤灰混凝土空心砌块（内填XPS板）、粉煤灰蒸压加气混凝土砌块三种新型围护结构材料为研究对象,将上述三种新型墙体材料砌成模拟实验房,与传统粘士实心砖同条件下进行热工性能对比试验研究,并进行微观结构机理分析,结果表明三种新型墙体材料保温隔热性能具有明显的提高,可作为夏热冬冷地区自保温砌块应用。     

Influence of fly ash fineness and shape on the porosity and permeability of blended cement pastes

The effects of the fineness and shape of fly ash on the porosity and air permeability of cement pastes were investigated. Pulverized coal combustion (PCC) fly ash and fluidized bed coal combustion (FBC) fly ash classified into three different finenesses were used. River sand with particle size distribution similar to that of fly ash was also used for comparison. Portland cement was replaced with fly ash and ground sand at the dosages of 0, 20wt%, and 40wt%. A water-to-binder ratio (w/b) of 0.35 was used thr...     

Paste-like self-flowing transportation backfilling technology based on coal gangue

A paste-like self-flowing pipeline transportation backfilling technology with coal gangue as aggregate is proposed to remove the potential damage caused by coal gangue piles. As well, the difficult problems of recovering high quality safety coal pillars and deep mining of the Suncun Coal Mine (SCM), Xinwen Coal Group, Shandong are resolved. The physical-chemical properties of coal gangue, optimized proportion of materials, backfilling system and craft in the SCM were studied in the laboratory and then an industrial test was carried out on high quality coal pillars under a town. The results show that finely crushed kaolinized and fresh gangue with granularity less than 5 mm can be used as aggregate with fly ash to replace part of the cement and a compos-ite water reducer as an additive, accounting for 1.0%-1.5% of the total amount of cement and fly ash. The recommended proportion is I(cement):4(fly ash): 15(coal gangue), with a mass fraction of 72%-75%, theological paste-like properties and a strength of more than 0.7 MPa at 7 d. The sequence of adding cement, fly ash, water reducer and then coal gangue ensures that the suspended state of the slurry, reducing the wear and jam of pipelines. The working face is advancing continuously by the alternating craft of building block walls with coal gangue and backfilling mined-out gobs with paste-like slurry. The recovery rate is as high as 90% with a backfilling cost of 36.9 Yuan/t, good utilization of coal gangue and no subsidence on the surface. This technology provides a good theoretical basis and application experience for coal mines, cement backfilling with paste-like slurry.     

Effect of MSWI fly ash and incineration residues on cement performances

The activities of municipal solid waste incineration (MSWI) fly ash and incineration residues were studied contrastively, through the component analysis and the activity ratio tests. The mechanical properties, hydration mechanism and leaching toxicity of the hardened cement paste mixing with MSWI fly ash and incineration residues were investigated. The experimental results indicated that the active constituents (CaO+Al₂O₃+Fe₂O₃) in MSWI fly ash were higher than those in incineration residues. Therefore the activity ratio of MSWI fly ash was 43.58%, twice as much as that of incineration residues. Meanwhile, the hydration of cement was delayed by mixing with MSWI fly ash and incineration residues, which also reduced the cement strength markedly. By adding with exceeding 20% MSWI fly ash, the specimens expanded and microcracks appeared. The leaching toxicities of cement pasted mixed with MSWI fly ash and incineration residues were lower than the Chinese national standard. Accordingly the cement mixed by MSWI fly ash and incineration residues can be considered as the environment-friendly materials.     

高电压技术对粉煤灰活性的超激发作用

粉煤灰属于重点治理的固体废弃物之一 ,目前国内外建材行业已综合利用粉煤灰的这一废物资源 ,生产出粉煤灰硅酸盐系列建材如粉煤灰水泥等。而粉煤灰硅酸盐建材具有许多优良特性 ,但最大的缺点是早期凝结强度低。若能释放粉煤灰的潜在活性 ,就可以大量使用粉煤灰。经过特制相应的粉煤灰活性激发剂 ,应用现代高电压技术 ,生产活性粉煤灰 ,解决了释放粉煤灰的潜在活性这一问题 ,为高掺量粉煤灰水泥的配制开辟新前景     

改性钙型粉煤灰对印染废水的处理

煤炭燃烧会排放出大量的燃烧废弃物——粉煤灰.无论是从能源还是环境保护角度看,都是应重视的问题.改性粉煤灰具有良好的吸附性.以钙型粉煤灰对不同印染废水处理后的CODcr进行了测定,证明改性钙型粉煤灰处理印染废水有很好的效果.     

粉煤灰廉价吸附剂资源化利用的现状和对策分析

粉煤灰是燃煤电厂排放的固体废弃物,其大量堆积造成环境污染和资源浪费,对粉煤灰的资源化利用近年来引起人们的广泛关注.粉煤灰呈多孔结构,具有良好的吸附性能,可用作处理废水中污染物质的廉价吸附剂.本文对粉煤灰吸附剂在水污染治理中的研究现状进行分析和总结,在此基础上,根据粉煤灰的组成和性质,提出粉煤灰资源化利用的方向为化学处理提高吸附性能和成型造粒以利于其工业化利用.     

利用垃圾焚烧飞灰固化污染底泥的实验研究

为探讨利用垃圾焚烧飞灰代替水泥进行污染底泥固化的可行性,研究了不同配比的底泥、水泥、垃圾焚烧飞灰的固化体抗压强度及浸出毒性.结果表明：固化剂中用20%的垃圾焚烧飞灰替代10%的水泥配置的固化体7.d,其抗压强度可达0.24.MPa,重金属浸出浓度低于毒性标准,固化体可进入固废填埋场填埋处置.     

芒硝工业尾矿制备碱激发偏高岭土胶凝材料

土壤聚合物是一种具有发展潜力的碱激发胶凝材料.尝试利用榆林地区煤系高龄岩和内蒙地区一种价格低廉的芒硝工业尾矿来制备偏高岭土基胶凝材料的可行性.研究结果表明:试验所用废芒工业尾矿与偏高岭土混合所成型的试块不能凝结硬化. 添加5%NaOH可使该材料凝结硬化并具有一定的强度. 采用硅酸钠碱溶液外掺15%废芒硝工业尾矿能够有效消纳固体废弃物制备碱激发偏高岭土基胶凝材料,抗压强度达到42.5水泥强度等级的要求.     

垃圾焚烧灰用于水泥混合材的研究

研究了垃圾焚烧灰用于水泥混合材的可能性.以不同比例的焚烧炭掺入水泥,测定水泥的各种物理性能.结果表明,炉底灰具有一定活性,水泥各项物理性能正常,可用于水泥混合材;飞灰活性较差,有害物含量较高,对水泥性能影响较大,不宜大量掺入.     

粉煤灰资源特性及其高附加值综合利用研究分析

粉煤灰是排放量最大的工业废渣，对其进行高附加值资源化综合利用对我国经济和环境具有重要的意义．至今对粉煤灰的利用研究已经取得了很多成果，但大多都是用于建筑材料工业中．尚有大部分粉煤灰未加利用，或被填埋或被堆放．而堆放和填埋粉煤灰需要占用大量可耕地和付出较高维护费用，长期的堆放还会造成大气污染和地下水系污染，给社会带来严重的经济和环境问题．近来的研究表明，粉煤灰除了可作为低附加值用于传统的建筑材料外，还可作为高附加值用于耐火隔热材料、污水治理、钢铁冶炼晶粒细化与阻氧覆盖、氧化铝溶出回收及其它功能材料中．     

Performance of cemented coal gangue backfill

Possibility of cemented gangue backfill was studied with gangue of Suncun Coal Mine, Xinwen Coal Group, Shandong, and fly ash of nearby thermal power plant, in order to treat enormous coal gangue on a large scale and to recovery safety coal pillars. The results indicate that coal gangue is not an ideal aggregate for pipeline gravity flow backfill, but such disadvantages of gangue as bad fluidity and serious pipe wear can be overcome by addition of fly ash. It is approved that quality indexes such as strength and dewatering ratio and piping feature of slurry can satisfy requirement of cemented backfill if mass ratio of cement to fly ash to gangue is 1：4：15 and mass fraction of solid materials reaches 72%-75%. Harden mechanism suggests that the cemented gangue fill has a higher middle and long term comprehensive strength.     

The Cement Solidification of Municipal Solid Waste Incineration Fly Ash

The chemical composition, the content and the leachability of heavy metals in municipal solid waste incineration （ MSWI） fly ash were tested and analyzed. It is shown that the leachability of Pb and Cr exceeds the leaching toxicity standard, and so the MSWI fly ash is considered as hazardous waste and must be solidifled. The effect of solidifying the MSWI fly ash by cement was studied, and it is indicated that the heavy metals can be well immobilized if the mass fraction of the fly ash is appropriate. The heavy metals were immobilized within cement hydration products through either physical fixation, substhtaion, deposition or adsorption mechanisms.     

基于骨架构建污泥固化体收缩与开裂特性的研究

针对传统污泥固化方法中固化污泥体易收缩开裂等问题,基于骨架构造原理,用煤矸石作为骨料,加入水泥、生石灰、粉煤灰等固化材料,按照不同配比对污泥进行一系列的固化实验。考察了在28 d养护龄期污泥固化结实体的开裂与收缩特性。研究表明加入煤矸石作为骨料能有效地抑制固化污泥的收缩与开裂,生石灰能抑制开裂,粉煤灰对污泥固化体的收缩开裂特性影响较小。     

外掺材料对多孔水泥混凝土胶浆强度的影响研究

文章采用超细粉煤灰与硅灰的复合技术配制多孔水泥混凝土水泥浆体试件.通过与双掺硅灰和减水剂、双掺粉煤灰和减水剂以及复合掺粉煤灰、硅灰和减水剂的情况对比,系统研究了硅灰粉煤灰作为外掺挤对多孔水泥混凝土水泥浆体的强度的影响.实验结果表明,由于硅灰与超细粉煤灰的复合,在水泥浆体形成过程中,这2种材料充分发挥了各自的功能效应,使得多孔水泥混凝土水泥浆体的强度性能显著提高.文章通过扫描电镜试验,剖析了超细粉煤灰与硅灰复合效应的机理,论证了用超细粉煤灰和硅灰以及减水剂复合配制多孔水泥混凝土水泥浆体的可行性.     

Applied technique of the cemented fill with fly ash and fine-sands

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自燃煤矸石细粉、粉煤灰制备泡沫混凝土的试验研究

本研究利用硅酸盐水泥和自燃煤矸石细粉、粉煤灰等混合材料,采用预制气泡后混合的方法制备出高性能泡沫混凝土,并研究了自燃煤矸石细粉、粉煤灰泡沫混凝土的干表观密度对泡沫混凝土的抗压强度与导热系数的影响。研究结果表明,随自燃煤矸石细粉、粉煤灰泡沫混凝土干表观密度的增加,泡沫混凝土抗压强度和导热系数也增加。     

低水胶比下工业废渣与水泥熟料的相互作用

探索了工业废渣与水泥熟料相互作用的定量指标.以掺惰性材料———刚玉粉的水泥水化样作参比样,研究和分析了低水胶比下粉煤灰、煤矸石与水泥熟料的相互作用.实验中粉煤灰掺量为10%~80%,煤矸石掺量为20%~60%,龄期为1~672 h.结果表明,水泥中掺入粉煤灰和煤矸石,由于水泥熟料用量降低而产生的稀释作用促进了水泥熟料的水化,而其他物理化学作用则依工业废渣的掺量、水化样龄期的不同而表现为促进或延缓水泥熟料的水化.     

Adsorption mechanism of polycarboxylate-based superplasticizer in CFBC ash-Portland cement paste

Circulating fluidized bed combustion （CFBC） ash exhibits the desirable pozzolanic activity which makes it a potential supplementary cementitious material to replace cement for concrete production. However, the high unburnt carbon content and porous surface structure of CFBC ash may adsorb water reducer and thereby significantly reduce the efficiency of water-reducing agents. The adsorption mechanism of polycarboxylate superplasticizer in CFBC ash-Portland cement paste was investigated by ultraviolet-visible spectrophotometer, and the conception of ＂invalid adsorption site＂ of CFBC ash was presented. The results show that the adsorption behavior of polycarboxylate superplasticizer in coal ash-Portland cement paste can be described by Langmuir isothermal adsorption equation. The adsorption capacity of CFBC ash-Portland cement paste is higher than that of pulverized coal combustion （PCC） fly ash-Portland cement paste. Moreover, the adsorption amount of polycarboxylate superplasticizer increases with the ratio of ash-to-cement in the paste. At last, the fluidity of CFBC ash-Portland cement paste is lower than that of the PCC fly ash paste. This work suggests that when CFBC ash is used as concrete admixture, the poor flowability of the cementitious system due to the high adsorption of water and water-reducing agent should be taken into consideration.     

高性能混凝土及不同配合比方案的应用研究

高性能混凝土的研究与应用,对于高面板坝工程混凝土面板的防裂具有重要意义.在原材料中合理掺入外加剂、粉煤灰、有机纤维等配料是获得高性能混凝土的重要途径.根据具体的工程情况,可采用不同的配合比方案,如外加剂+粉煤灰+有机纤维"多掺"方案、联掺或单掺高效减水剂+引气剂方案等.配制高性能混凝土,应尽量选择高标号的硅酸盐水泥或普通硅酸盐水泥,并应根据水泥中活性混合材料的类型及含量,合理确定粉煤灰的最佳掺量.实践证明,通过优化混凝土配合比,可减少甚至避免混凝土面板裂缝的产生.