Characterization of Fired Clay Bricks for an Economic Contribution of the Exploitation of Thicky Clay Deposit

Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical, geotechnical, and thermal studies carried out did lead to a better comprehension of the potential of the area for clay production. It also allowed determining the physical and chemical characteristics of the clays for their use in order to make fired clay bricks. Different types of fired clay brick were produced with Thicky’s clays. The study of the physical, mechanical and thermal parameters of these raw materials and bricks has given very satisfactory results compared to the standards in use. It is noted a good ceramic behavior, and there is no deterioration observed after firing at 900°C until low residual moisture of about 3% (on a dry basis), a smooth texture with a beautiful appearance, a low loss on ignition, a low shrinkage value of less than 1% (dry), moderate water absorption and also good compressive strength. The study of thermal properties on a brick wall by the asymmetric lime plane method gives satisfactory effusivity and thermal conductivity values which are respectively equal to 746.48 J·K-1·m-2·s-1/2 and 0.42 W·m-1·k-1 with a thermal resistance of 0.0028 m2·K·W-1.

Properties of Geopolymers Made from Fired Clay Bricks Wastes and Rice Husk Ash (RHA)-Sodium Hydroxide (NaOH) Activator

High cost has been pointed among factors that limit the promotion of geopolymers. To contribute to the reduction of the use of costly industrial sodium silicate in activators for geopolymers, a gel obtained with RHA and concentrated sodium hydroxide was used in the present study to develop an alkaline activator with 8 M NaOH and to produce geopolymers with crushed fired clay bricks wastes (FCBW). Characteristics of the gel were compared to that of commercial sodium silicate which was also mixed with 8 M NaOH in the ratio 1:1 to produce geopolymers. Chemical and mineralogical analyses were done on raw materials. Fourier Transformed Infrared Spectroscopy (FTIR) was done on the gel, commercial sodium silicate and products. Biaxial four point flexural strength, bulk density, water absorption and scanning electron microscopy (SEM) tests were also done on products. Results showed that RHA-NaOH alkaline activator has good potential in consolidating FCBW powder through geopolymerization process which gave products that had characteristics not far from that when the commercial sodium silicate was used. The gel obtained by mixing RHA and NaOH can contribute to the reduction of the use of costly commercial sodium silicate in the production process of geopolymers. However, appropriate filtration process is needed for the RHA-NaOH gel to reduce its impurities as undissolved entities, which will consequently contribute to improve the flexural strength, the density and the microstructure of its products which were low compared to when commercial sodium silicate was used.

Evolution of Fire-sealing Gable Walls' Diversity in Leizhou Traditional Vernacular Red-brick Dwellings

Peculiar color and form of Leizhou red-brick folk dwelling distinguishes it from other vernacular dwellings in Lingnan region(south of the Five Ridges, referring to the current Guangdong and Guangxi). The fi re-sealing gable wall(hereinafter referred to as fi re-sealing wall) in brilliant colors, diversifi ed forms and exaggerated shapes is a remarkable symbol of local dwellings. Originating from Fulao traditional vernacular dwelling and inheriting its advantages, fi re-sealing wall of Leizhou red-brick vernacular dwelling has shown diversity for the infl uence of immigrants, regional cultures, social background and economic status, and formed its own features in color, form and decoration. On the basis of fi eld investigation, this paper described diversifi ed features of the fi re-sealing wall of Leizhou red-brick vernacular dwelling, analyzed the causes of its diversity from the perspectives of aesthetics, function and technology, and explored the harmonious living philosophy implied by its function, form and art.

Influence of Firing Temperature on Properties of High Alumina Bricks

To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused corundum powder,α-alumina micropowder,and Suzhou soil as the matrix,firing at different temperatures(1420,1440,1460,1480,1500 and 1520℃)for 4 h.The apparent porosity(AP),the bulk density(BD),the cold crushing strength(CCS),the thermal shock resistance(TSR),the refractoriness under load(RUL)and the creep rate of the samples were tested.The effects of the firing temperature on the creep rate(1450℃×50 h,under a load of 0.2 MPa)of the samples were studied.The results show that with the sillimanite addition of 22.5 mass%,the sample fired at 1460℃for 4 h performs the best comprehensive properties:the AP of 17.5%,the BD of 2.75 g·cm^(-3),the CCS of 100.5 MPa,the TSR number of 35 cycles,the RUL of 1682℃,and the creep rate of-0.428%,which can prolong the service life of furnaces.

铁尾矿废石免烧透水砖制备及性能研究

以铁尾矿废石、水泥和铁尾矿粉为原材料,静压成型制备铁尾矿废石免烧透水砖,研究了成型压力、保压时间、养护时间、水胶比、孔隙率对透水砖抗压强度、透水系数的影响,通过SEM分析样品的微观形貌。结果表明:配合比设计参数为设计孔隙率20%,水泥10%,铁尾矿粉10%,铁尾矿废石80%,水胶比0.4,减水剂掺量为1.5%;透水砖的最佳工艺条件为成型压力8 MPa,保压时间50 s,标准养护28 d,在此条件下制得的透水砖抗压强度为10.4 MPa,透水系数为2.24×10^(-2) cm/s。

高温后烧结普通砖砌体抗剪性能试验研究

既有砖砌体结构建筑发生火灾后,砂浆强度、砖与砂浆的粘结性能均有较为明显的下降,进而影响砌体的抗剪性能及抗震性能。为了解高温后烧结普通砖砌体抗剪性能的下降规律,制作了砌筑烧结普通砖砌体试件36个,分别开展常温、200、400℃和500℃后的剪切试验,测试不同温度环境下试件的温度场,绘制常温、200、400℃和500℃后试件剪切荷载-位移曲线。结果表明:相比于常温下烧结普通砖砌体抗剪强度,随着温度环境升高,试件的抗剪强度降低;烧结普通砖砌体试件发生剪切破坏时,变形在2mm以内,为典型的脆性破坏;在同一温度环境下,伴随烧结普通砖砌体水泥砂浆强度增大,试件的抗剪强度和峰值位移随之增大;使用同等强度水泥砂浆,伴随温度环境的升高,试件抗剪强度降低,峰值位移稍稍增加;拟合高温后烧结普通砖砌体残余抗剪强度,提出高温后烧结普通砖砌体抗剪强度计算方法,抗剪强度计算值与试验值吻合较好。

高温后烧结普通砖砌体剪压复合抗剪性能试验研究

为了研究砖砌体结构在高温后的剪压复合受力性能,制作了84个砌体试件,进行了在不同高温后不同轴压比下的抗剪试验,得出砌体在高温后的抗剪强度和轴压比之间的变化规律,对高温后砌体试件在不同轴压比情况下的延性进行了分析。结果表明:在相同温度下,随着轴压比增大,砌体抗剪强度增大;轴压比一定时,随着温度升高,砌体抗剪强度减小。在0.1~0.5轴压比范围内,同一温度下,随着轴压比增加,砌体的延性不断增大;轴压比相同时,随着温度的升高,砌体延性逐渐降低。以常温下相同压应力为基准,200℃以内,轴压比为0.3时试件出现剪压破坏;400℃以上,轴压比为0.2时试件出现剪压破坏,高温使砌体剪压段提前。基于变摩擦系数的剪摩理论,计算出普通砖砌体抗剪强度公式的变摩擦系数;结合高温后砖砌体纯剪强度公式,得到以温度为变量的高温后砖砌体剪压复合抗剪强度计算公式。

白云尾矿与转炉渣制备烧结透水砖及性能研究

为充分利用白云鄂博再选尾矿和包钢转炉渣,以其为原料采用高温煅烧的方式制备烧结透水砖。结果表明:选定钢渣骨料级配5~10 mm∶2.5~5 mm∶0~2.5 mm=4∶3∶3,最佳方案为尾矿掺量25%,成型压力30MPa,烧结温度1180℃,保温时间50 min,此时透水砖的粘结相为镁铁尖晶石相和硅酸钙相,抗压强度为28 MPa,透水系数为0.091 cm/s,均优于国标《烧结普通砖》(GB/T 5101-2017)中MU25(25 MPa)的抗压强度要求和《透水路面砖和透水路面板》(GB/T 25993-2010)中A级0.02cm/s的透水系数要求。

12级LTD脉冲源触发支路气体开关击穿特性

12级串联太瓦级直线型变压器驱动源(LTD)采用内置时序触发新方法,对触发支路气体开关提出了低自放概率、低触发阈值、低抖动、触发延时可调的技术要求。介绍了自行研制的基于电阻均压/电晕辅助触发技术的气体开关结构和工作原理;建立了气体开关特性测试平台,完成了12只气体开关的老练和击穿特性测试;开关应用于12级LTD脉冲源级联触发实验,获得了不同工作电压、工作系数下的触发特性参数。实验结果表明:开关工作电压±60~±80 kV,工作系数60%~80%,抖动小于2 ns,500余发实验未发生自放电,实现了12级LTD脉冲源触发支路按理想时序依次导通,触发时序系数0.83~1.17范围内可调。

全固废烧结砖的制备及性能研究

以建筑渣土、黄河沉积沙以及污泥为原材料制备全固废烧结砖,借助XRD、XRF、SEM等手段对原材料进行了详细的理化性质测试,确定了坯体的最佳制备方法及烧结制度,探究了含水率及黄河沉积沙掺量对烧结砖力学性能的影响规律。结果表明:含水率为25%时坯体水分挥发稳定,此时砖体烧结强度高;黄河沉积沙取代率为30%时坯体内形成完整的骨架结构,烧结砖强度增加;在每2个梯度间进行2 h保温处理,可为物质反应及气体挥发提供所需外部环境,提升烧结质量;烧结砖内部存在高温冷却后形成的由玻璃相以及主晶相构成的砖体骨架,使砖体具有良好的结构稳定性及力学强度;在含水率为25%、黄河沉积沙取代率为30%时,砖体强度达到29.3 MPa,吸水率为9.9%,符合工程用砖要求。通过原材料处理、配比设计、坯体成型、烧结工艺等方面对烧结砖的制备工艺进行研究,为全固废烧结砖的生产制备提供了理论依据。

SonReb法在北京明代古青砖抗压强度评估中的应用

以北京某明代古城墙烧结粘土砖为研究对象,采用回弹法、超声法等无损检测方法对北京明代青砖进行力学性能测试,同时进行单轴抗压强度试验。在此基础上,采用线性函数式和幂函数分别将回弹值(Rebound Number)和超声脉冲速度(Ultrasonic Pulse Velocity)与强度试验结果进行拟合;同时,采用超声-回弹综合法(SonReb)结合线性拟合、非线性拟合和响应面分析法(Response Surface Methodology)建立了试块的强度预测模型,并对不同模型精度进行了对比分析。结果表明:采用综合法预测北京城墙砖单轴抗压强度具有更高的可靠性,其预测精度较使用单一的检测方法更为精确。研究结果可为快速无损获取古青砖强度指标提供依据和参考。

微晶砖坯体配方及烧成温度的研究

本研究主要围绕微晶砖坯体配方及烧成温度展开研究。通过对微晶砖坯体配方的深入分析,结合实验数据,探讨了不同原料比例对微晶砖坯体性能的影响。在此基础上,研究了微晶砖坯体烧成温度对产品质量的影响。通过对烧成温度的调整,优化了微晶砖坯体的烧结效果,提高了产品的力学性能和表面质量。对微晶砖坯体配方与烧成温度进行了综合优化,并展望了其在建筑材料领域的应用前景。为微晶砖坯体的生产工艺提供了重要的理论和实验基础,具有一定的研究意义和应用价值。

石煤提钒尾渣基钙长石烧结砖的烧结及重金属固化机理

这是一篇陶瓷及复合材料领域的论文。石煤提钒尾渣是一种危险的工业废弃物,综合利用石煤提钒尾渣具有重要的环保与经济意义。本研究以石煤提钒尾渣为主要原料制备了建筑用烧结砖,研究了烧成温度对样品结构和性能的影响规律,探究了Cu、V和Zn重金属浸出活性的钝化机理。结果表明:烧成温度显著影响烧结砖的相组成、显微结构和性能。适当提高烧成温度不仅有助于石英与原料中的碱性物质反应,生成富硅液相,提高样品的致密度,而且促进了黄长石向钙长石转变及莫来石生成。这些晶相与玻璃相互胶结,赋予制品较高的致密度和抗压强度。此外,提高烧成温度增大了制品中Cu、V和Zn的残渣态含量,减小了制品的孔径与孔容积,从而实现了Cu、V和Zn的固化。采用烧成温度为1 200℃,保温时间为3 h的工艺制度,制备出的建筑用烧结砖的各项性能均满足《烧结普通砖》(GB/T 5101—2003)中Mu25等级的要求,且制品的Cu、V、Zn重金属浸出浓度均低于标准值。研究结果为石煤提钒尾渣的综合利用提供了新的思路。

焦炉边火道温度低的原因分析及处理方案

为解决安泰集团焦化厂二炼焦车间JN60型焦炉出现的边火道温度低,个别火道窜漏导致燃烧不正常的问题。通过现场了解边火道温度现状,从数据出发分析出现此情况的原因是管砖破裂。采用更换管砖和喷补灌浆处理的方法,解决了边火道温度低的问题。为同行业同类型焦炉提供技术参考和借鉴。

电解锰渣制备免烧铺路砖生态环境风险分析

以电解锰渣为原料,采用半干压成型工艺生产免烧铺路砖产品。首先从产品重金属全量、浸出毒性方面评价产品的生态安全性,然后再通过室外长期雨水淋溶实验及室内盆浸试验分析锰渣免烧铺路砖中污染物的释放行为,评估锰渣基路砖的生态环境风险。通过对锰渣免烧铺路砖生态环境风险评估发现,锰渣免烧铺路砖产品中的氨氮极容易释放到环境中,存在较大的环境风险;锰渣免烧铺路砖产品中的重金属则较为稳定,环境风险较低。

烧结装饰砖与烧结路面砖生产与应用

全面总结了生产烧结装饰砖和烧结路面砖的工艺特点,如硬塑挤出成型技术、天然气外燃隧道窑等工艺技术,并且对其在实际工程中的应用做了介绍,对传承和发展烧结装饰砖和烧结路面砖具有借鉴意义。

烧结砖泛霜试验标准解读

随着墙体材料革新工作的推进,大部分生产企业采用煤矸石、污泥、粉煤灰、建筑渣土等固废生产烧结砖,由于部分企业在产品出厂检验时,对标准不能熟练掌握和理解,导致出厂把关不严,致使泛霜等质量不合格的产品流入市场,给建筑工程质量带来安全隐患。就此问题,对烧结砖中泛霜试验的质量标准和试验方法做出解读,帮助检验人员提高检验能力。

关于GB/T 25031-2010值得商榷的一些问题及建议

列举了GB/T 25031-2010《城镇污水处理厂污泥处置制砖用泥质》中存在的一些问题,并展开详细探讨,提出了修改建议。

烧结砖瓦产品二氧化碳排放情况及排放量核算

结合烧结砖瓦原料、燃料、工艺等特点,分析了烧结砖瓦产品二氧化碳排放特点和排放量情况,参考同类产品企业的二氧化碳排放量核算标准和方法,探讨了烧结砖瓦企业的二氧化碳排放量核算方法和其他相关问题。

掺入聚合废料对烧结黏土砖热效率和耐久性影响研究

研究在烧结黏土砖中使用膨胀聚苯乙烯(EPS)和废橡胶轮胎粉(WRTP),以打造环保和清洁的建筑。将不同比例的EPS和WRTP与黏土混合,在1000℃下烧结,先进的材料表征技术用于评估材料,并对砖进行了物理、力学和耐久性测试。高剂量的EPS和WRTP提高了砖的热效率,减轻了砖的重量。该研究为EPS和WRTP在生产清洁和可持续的聚合物废砖方面提供了宝贵的经验,以期提高砖的性能。