Pore Structure Characteristics of Baking-Free Slag-Sludge Bricks and Its Correlations to Mechanical Properties

In order to explore the relationship between the macroscopic properties and pore structure characteristics of baking-free slag-sludge bricks,the compressive strength and water absorption rate using aluminum industrial slag and sludge of different substitution rates were tested.Optical instruments and image analysis software were used to measure the parameters of the pore structure.Specifically,a fractal model was built based on the fractal theory,in which the fractal dimension was used as the characteristic index of the pore structure to analyze the correlation and interaction mechanism between the fractal dimension and the macroscopic mechanical properties.Based on this study,conclusions were drawn as follows:(1)The plane pore structure of baking-free bricks shows good fractal characteristics.With the increase of the aluminum industrial slag content,the fractal dimension becomes smaller and the pore structure develops well;with the increase of the sludge content,the fractal dimension becomes larger and the pore structure becomes worse;(2)As the fractal dimension of the plane pore structure increases,the compressive strength of baking-free bricks falls,and the porosity and water absorption rise;(3)The optimum content of baking-free slag-sludge bricks is aluminum industrial slag 30%and sludge 10%.After 7 days of curing,baking-free bricks boast higher performance,and fully meet the performance requirements of solid concrete bricks(MU40),which can reduce time costs,and enhance enterprise revenue.

Study on Mechanical Properties and Action Mechanism of Leather Industrial Sludge Aggregate Baking-Free Bricks

Taking an industrial sludge and its preparation of sludge wrap shell aggregates(WSAs)instead of sand to prepare baking-free brick as the research object,the development law of mechanical properties and the influence mechanism of macro and micro characteristic parameters of the bricks under different sludge and WSAs replacement rates were studied through the macroscopic mechanical properties test,with the help of nuclear magnetic resonance(NMR),transmission electron microscopy-energy spectrum and other testing technology and pores and cracks analysis system(PCAS)software.The results showed that the compressive strength of each sample decreased with the increase of sludge content.When the sludge content was less than 30%,it was mainly affected by the water-binder ratio.When the sludge content was more than 30%,it was mainly affected by the sludge content.At the age of 7 days,with the increase in replacement rate of WSAs,the compressive strength of the S10 and S30 groups was higher than that of the control group.The compressive strength of the S50 experimental group was 30.38 MPa,and the loss of compressive strength was slight compared with the control group.The water absorption rate of the 28 days S100 experimental group increased by 10.71%compared with the control group.When the content of WSAs was less than 50%,the holes above 0.1μm in the brick can be reduced and transformed into smaller holes,with a decreasing trend of the plane porosity of the brick.The microscopic results of the baking-free brick showed that the three-phase system of WSAs-interface transition area-mortar was poorly bonded and delaminated compared with the gravel aggregate-interface transition area-mortar system,and damage was more likely to occur in the WSAs and interface transition area.The above results show that it is feasible to use sludge and WSAs instead of sand for the preparation of baking-free bricks.This technology not only solves the problem of sludge disposal,but also protects the over-exploitation of mineral resources,and the technology has a broad application prospect and market value.

Fabrication of Baking-Free Bricks Using Gold Tailings and Cemented Materials with Low Alkalinity

The purpose of this paper was using gold mine tailings and cemented materials with low alkalinity to fabricate baking-free bricks.The obtained baking-free brick samples were evaluated by unconfined compressive strength(UCS),water absorption percentage,freezing-thawing cycle,and drying-wetting cycle.The microstructures of the baking-free brick samples were analyzed using X-ray diffraction(XRD)and scanning electron microscope(SEM)techniques.The baking-free brick specimens cured for 28 days with the addition of 10%mixing water consumption and 1:6 cement/tailing ratio tended to obtain favorable comprehensive properties such as a high compressive strength of 15.15 MPa,a low water absorption percentage of 11.8%,excellent freezing-thawing resistance with a 8.9%UCS loss rate after 15 freezing-thawing cycles and good drying-wetting resistance with a 11%UCS loss rate after 10 drying-wetting cycles.The XRD and SEM test results verified that different kinds of hydrate products including C-S-H and C-S-A-H gels,and ettringite were produced during hydration process,which were responsible for good physical,mechanical properties,and durability of the obtained baking-free bricks.Therefore,the experimental results showed that it was practical and reasonable to utilize the homemade cementitious materials in our laboratory to stabilize the gold tailings for production of baking-free bricks,which still met the requirements of major regional construction standards in some countries.

Properties Evaluation of Concrete using Local Used Bricks as Coarse Aggregate

With time concrete / reinforced concrete has become the popular material for construction. Modern industry utilizes this material a lot and has produced various beautiful, eye catching and amazing structures. Due to modern requirements for living and developed construction industries, the old buildings (usually constructed with brick masonry) are demolished and are replaced with new modern buildings. Demolition of buildings results in waste materials which can create waste related problems and environmental issues. By using recycled aggregates weight of concrete can also be reduced, which can also solve problems related to self-weight of concrete. In this paper attempt has been made to use local used bricks from vicinity of Nawabshah, Pakistan, as coarse aggregate. Concrete cubes made with local recycled bricks are cast and tested for overall weight of concrete, moisture content, dynamic modulus of elasticity and compressive strength (nondestructive and destructive methods). The results showed that concrete derived from recycled aggregates attained lower strength than regular concrete. More detailed elaborated work is recommended with different mix ratios and different proportions recycled aggregates for better conclusions.

废弃黏土砖骨料轻质混凝土正交试验研究

将废弃黏土砖骨料应用于轻质混凝土中,可实现建筑垃圾再利用,同步节省建筑材料,改善轻质混凝土性能。以废弃黏土砖颗粒为骨料,开展轻质混凝土制备试验,研究不同水灰比、泡沫掺量、纤维掺量对废弃黏土砖骨料轻质混凝土的物理力学性能影响。结果表明:水灰比对吸水率影响显著,随着水灰比的增大,吸水率增加了27.03%,泡沫掺量对干密度、抗压强度和劈裂抗拉强度影响显著,随泡沫掺量的增加,干密度、抗压强度和劈裂抗拉强度减小了17.78%、52.52%和34.83%,并建立了抗压强度与干密度、劈裂抗拉强度之间的对应关系式。

废黏土砖骨料轻质混凝土物理力学性能试验研究

将废弃黏土砖破碎成骨料用于制备轻质混凝土,可同步达到资源再利用、降低环境污染、节省天然骨料的目的。为揭示废弃黏土砖骨料轻质混凝土的性能,通过室内试验对废砖骨料级配、废砖骨料体积率、水灰比、泡沫掺量等因素影响轻质混凝土的干密度、吸水率、抗压强度性能进行试验研究,结果表明:泡沫掺量对干密度和抗压强度影响显著,泡沫掺量由2%增加到5%时,干密度由1407kg/m^(3)减小到1128kg/m^(3),抗压强度由13.39MPa减小到4.66MPa,废砖骨料级配对吸水率影响显著,骨料级配从A组到C组级配时,吸水率由11.3%减小到5.7%。

工艺参数对抛光渣轻质陶瓷砖性能的影响

近年来我国陶瓷行业发展迅速,每年产生约1000万吨陶瓷抛光渣,但只有5%被利用。本文以陶瓷抛光渣作为研究对象,辅以球土、瓷片砂和中温砂等原料,以SiC为孔结构调控剂来制备轻质陶瓷砖,运用一系列正交试验得出最佳的烧结制度,并探究烧成温度与球磨时间对抛光渣轻质陶瓷砖的性能影响。结果表明,烧成温度的升高会改善轻质陶瓷砖内部连通孔和气孔均匀性,在1160℃时,轻质陶瓷砖的体积密度、抗压强度、显气孔率最大,分别为1.24 g/cm^(3)、35 MPa、20%,吸水率为20.38%;当球磨时间从10 min延长至110 min时,轻质陶瓷砖颗粒变细,表面能增大,液相量增多,发泡量增多,使连通孔、气孔均匀性得到改善。

柚子皮用于制作轻质普通砖的实验研究

对农业废弃物柚子皮用于制作轻质普通砖开展了研究。结果表明,利用柚子皮作掺合料制作轻质普通砖能够满足普通砖的相关质量要求。其中,在拌合物塑限一定条件下,当干燥的柚子皮粉掺入量不超过10%时可得到外观良好的砖坯;柚子皮粉末的掺入使砖的体积密度减少约100kg/m~3;随着柚子皮粉末掺入量的增加,煅烧后砖的抗压强度逐步降低,减少约18%,同时,提高煅烧温度有利于强度发展。

利用青海某铅锌矿尾矿制作轻质免烧砖的工艺研究

对青海某铅锌矿选别尾矿的化学成分、矿物组成及相对含量、粒度及其分布进行测试分析表明，该尾矿的矿物组成主要是石英、方解石、黄铁矿及绿泥石，粒度集中分布在20日～140目。以该尾矿作骨料，适量水泥作胶结科，石灰作激发剂，分别加入混凝土发泡剂和废弃聚苯泡沫粒作预孔剂。通过浇注、捣打成型、养护等工艺制备了轻质免烧砖。研究了不同原料配比和养护条件下制品容重和抗压强度争性能。当尾矿用量达70％～80％时，制品干燥容重仅为页岩实心砖的2／3，抗压强度最高可达到9．3MPa，适用于建筑物承重和非承重填充砌块，属低能耗环保型墙体材料。

利用废矿原料研制轻质外墙砖

利用珍珠岩废矿粉、本地资源瓷土、膨润土为原料,添加Fe2O3和还原碳粉作为发泡剂,制备出具有防水、保温功能的轻质外墙砖;探讨了原料配方、烧成工艺对制品吸水率、密度和抗折强度的影响;确定出了较理想配方和烧成工艺分别为:珍珠岩废矿粉43%、瓷土50%、膨润土7%、氧化铁2%、还原碳粉1%、烧成温度1180℃、保温时间10分钟。

浇注成型法制磷石膏轻质墙体砖的研究

研究磷石膏的预处理方法和浇注成型法制备磷石膏轻质墙体砖。通过实验考察了磷石膏预处理方式和成型方法对砖强度的影响,实验结果表明,采用煅烧,石灰中和,或者煅烧加石灰中和的方法处理后的磷石膏都能够用作制备磷石膏轻质墙体砖。采用石灰中和法处理磷石膏,浇注法成型,蒸养和自然养护的制砖工艺能够制备出满足JC422-91《非烧结普通粘土砖》标准要求的磷石膏轻质墙体砖。

有机纤维易燃物对轻质烧结页岩砖性能的影响

采用控制单一变量变化的方法，改变锯末和页岩的配比，研究不同配比下轻质烧结页岩砖的性能。结果显示，随着锯末与页岩配比的提高，砖体的烧失量、畸形率升高，质量、体积密度和抗压强度都下降。建议生产轻质烧结页岩砖时，控制有机纤维易燃辅料的占比为20％-30％，并且纤维辅料与页岩需搅拌均匀。

高掺量粉煤灰轻质节能免烧砖的研制

高掺量粉煤灰轻质节能免烧砖以粉煤灰为主要原料,加入部分陶粒、膨胀珍珠岩、砂、石粉等做骨料,并配以少量的钙质材料和微量的激发剂混合而成。通过优选原材料、配合比,设定合理的生产工艺等控制产品质量,其表观密度在1700～1900 kg/m3,强度等级不小于MU10,其他主要技术指标达到JC 2392-2001粉煤灰砖的标准。最后简单探讨了其增强机理。

利用四川某铜矿尾矿制作轻质免烧砖的工艺研究

对四川某铜矿选别尾矿的化学成分、矿物成分及相对含量、粒度及其分布进行测试分析表明,该尾矿的矿物成分主要是石英、钠长石,粒度集中分布在40～140目。以该尾矿作骨料,适量水泥作胶结料,石灰作激发剂,分别加入混凝土发泡剂和废弃聚苯泡沫粒作预孔剂,通过浇注和捣打成型、养护等工艺制备了轻质免烧砖。研究了不同原料配比和养护条件下制品密度和抗压强度等性能。当尾矿用量达70～80%时,制品干燥容重仅为页岩实心砖的1/2～2/3,抗压强度达到3.6～10.4MPa,适用于建筑物承重和非承重填充砌块,属低能耗环保型墙体材料。

再生砖轻骨料混凝土梁正截面抗弯性能研究

利用陶粒和以废砖为主的再生骨料制成7根不同再生砖骨料取代率(0,20%,40%,60%,80%,100%)的钢筋混凝土梁,通过正截面承载力试验,对相同强度等级的普通混凝土梁和再生砖轻骨料混凝土梁的正截面抗弯受力特点、破坏形式、裂缝开展特点、极限承载力,平截面假定进行了研究。对比分析2类梁受弯性能的异同点。试验结果表明:再生砖轻骨料混凝土梁与普通混凝土梁的受弯过程相似,都符合平截面假定,并且受取代率的影响较小。由于再生砖轻骨料混凝土梁质轻,与普通混凝土梁抗弯性能相差不大,具有一定的优越性,可以应用于工程中。

海涂厚层盐渍淤泥地基工程建设技术研究

为解决海涂的厚层软基和盐渍淤泥腐蚀问题,对海涂厚层盐渍淤泥地基上的工程建设实用性技术进行了研究与实践。利用室内试验研究了海涂淤泥、海涂淤泥加气混凝土废渣混合固化轻质土、海涂淤泥烧结砖和海涂淤泥烧胀陶粒的性质,利用现场试验研究了吹填海涂淤泥的浅层排水固结技术和微型钢管桩基础托换技术的处理效果。试验结论为：连云港海涂地基存在8~40 m厚的盐渍淤泥层,土性软弱,且对混凝土为弱等或中等腐蚀,对钢筋为强腐蚀;海涂淤泥加气混凝土废渣混合固化轻质土强度可控制在200~1000 k Pa之间,能用于滩涂地基上的路堤建设;在深厚海涂地基条件下预压排水固结处理后仍不宜作天然地基的吹填淤泥,推荐快速处理后用于桩基础地基;微型钢管桩托换能阻止深厚软基上浅基础的沉降,还能对原基础进行提升;含盐淤泥能替代粘土烧结成质量合格的砖或陶粒,烧结过程中盐分大大减少。

轻质烧结页岩砖抗冻性能试验

轻质烧结页岩砖是以页岩为基本原料、锯末为辅料研发的一种新型轻质烧结类墙体材料。分析了辅料锯末的含量分别为20%、25%、30%、35%情况下对轻质烧结页岩砖抗冻性能的影响。试验表明:轻质烧结页岩砖在15、25、35和50冻融循环次数下,质量损失与强度损失均随辅料含量的增加而增加;轻质烧结页岩砖应该随着不同使用地区而改变锯末的掺量从而达到满足抗冻指标的要求。

交叉肋自保温砖的优化设计及性能研究

通过优选制作原材料,分析自保温砖的块型、孔型和肋型,对交叉肋多孔自保温砖进行优化设计。以浮石砂,橡胶颗粒、聚苯颗粒、粉煤灰、水泥等为原材料,采用振动加压成型法,制备交叉肋复合轻骨料混凝土自保温砖,并对其热工性能和物理力学性能进行分析,得出该自保温砖的热阻为1.69(m^2·K)/W,空心率为27.1%,密度为881kg/m^3,抗压强度为6.5MPa,满足寒冷地区的外墙节能要求和力学性能要求。

茂名干馏页岩渣有效利用途径的探讨

通过干馏页岩渣的试验研究以及与燃烧页岩渣的比较,探讨了干馏渣的有效利用途径,提出了干馏页岩渣不仅可以替代黏土作为建筑材料,制取高强度的轻质空心砖、免蒸免烧实心砖,作为水泥混合料,而且还可以作为燃料,达到节煤的目的。通过上述油页岩渣的利用,可以达到废渣循环利用,不会产生二次废渣。

粉煤灰轻质隔热耐火砖的研制

利用电厂优质粉煤灰 ,加入少量辅助材料及复合结合剂 ,制成体积密度为 0 .6～ 1.0g/cm的轻质隔热耐火砖。制品掺灰量为 60～ 90 % ,无需粘土结合 ,导热系数小 ,热稳定性好 ,成本低 ,可替代漂珠砖用于冶金、机械。