保水材料在透水砖中的应用研究

以膨胀蛭石和高吸水树脂作为透水砖的保水材料制备高保水性透水砖。分析了膨胀蛭石和高吸水树脂掺量对高保水性透水砖的吸水性、保水性、透水系数及抗压强度的影响。结果表明,当膨胀蛭石掺量为石材质量的6%,吸水树脂掺量为石材和水泥总质量的0.6%时,高保水透水砖的综合性能最佳,吸水率较空白组增大4.5倍(为0.28 g/cm~3),保水性能提高3～4倍,抗压强度降低31%(为26.2 MPa),透水系数降低50%(为1.4×10~(-2) cm/s)。     

聚丙烯酰胺系高吸水树脂对水泥砂浆性能的影响

高吸水树脂(SAP)作为一种良好的吸水保水材料,可在水泥基材料中提供良好的内养护作用。实验通过对比研究了添加不同吸水倍率SAP及其不同掺入量对水泥砂浆流动度、抗折和抗压强度等工作性能的影响。研究结果表明,添加0.1%、1 500 g/g吸水倍率SAP的砂浆试块比普通砂浆试块28 d抗折、抗压强度分别提高了9.78%、22.55%,且添加SAP后砂浆试块的后期强度增长速率要高于普通砂浆试块,说明高吸水率、低掺量SAP对水泥砂浆具有良好的内养护作用,其工作性能有明显提升。     

透水铺装材料湿物理性质测定

为获取典型透水铺装材料的湿物理性质,以用于进行透水铺装热湿传递计算,进而科学评价其蒸发降温效果。以中国居住区广泛使用的3种透水铺装材料:烧结陶瓷透水砖(TC)、再生骨料混凝土透水砖(ZS)和普通透水砖(PT)为研究对象,参考相关标准,采用真空饱和实验测试了透水铺装材料的表观密度ρ、开放孔隙率及真空饱和含湿量wvac;采用单面浸泡实验测试了毛细饱和含湿量wcap及吸水系数A;采用渗透实验测试了其渗透系数kT。通过对测试结果进行误差分析,建立了透水铺装材料与液态水相关的湿物理性质数据库。通过对比3种材料测试数据发现:保水性能方面,ZS最优、PT次之、TC最差;吸水性能方面,TC最优、PT次之、ZS最低,表明材料保水与吸水性能并非正相关;渗透性能方面,TC性能最优、PT次之、ZS最弱,在满足渗透性能的前提下,PT最有利于吸水后的蒸发降温。     

阳离子交换树脂提取活性污泥胞外聚合物的研究

采用阳离子交换树脂提取活性污泥中的胞外聚合物(EPS),结果表明:001×7凝胶型阳离子交换树脂的提取效果优于D001大孔型阳离子交换树脂;液相的pH值对EPS的提取效果影响较大,当pH值为5.8～7.8时提取效果比较稳定;与高速离心分离提取法相比,中速离心结合抽滤的分离方法能得到更多的腐殖酸;蛋白质为EPS的最主要组分,多糖与腐殖酸次之;当001×7树脂的投量为80g/gVSS、搅拌速度为500r/min、搅拌时间为1～3h时,对EPS的提取效果较好,提取效率为10%～15%,并且细胞破损量小。可见,001×7凝胶型阳离子交换树脂法是一种较优的EPS提取方法。     

透水砖吸水及保水性能研究

吸水及保水性能是影响透水砖蒸发降温效果的重要因素。现今多采用整体浸泡实验获得的浸泡饱和质量含水率来描述透水砖在自然状态下所能保存的最大水量,但采用何种实验方法及指标描述透水砖的吸水性能仍然有所欠缺。本文以烧结陶瓷透水砖(陶瓷砖)、再生骨料混凝土透水砖(再生砖)和普通混凝土透水砖(普通砖)为研究对象,采用整体浸泡实验、单面浸泡实验和人工模拟降雨实验,测试了砖体含水率随时间的变化规律,并比较了3种实验方法测试结果差异。结果表明:可采用毛细吸水系数Aw描述透水砖的吸水性能,陶瓷砖、普通砖和再生砖的Aw值分别为2.1 kg/(m~2·s~(0.5)),0.07 kg/(m~2·s~(0.5))和0.03 kg/(m~2·s~(0.5)),表明陶瓷砖吸水速度比再生砖快70倍;应采用单面浸泡饱和质量含水率W_(sat)描述透水砖的保水性能,陶瓷砖,再生砖和普通砖的W_(sat)值分别为7.15%,10.25%和6.27%,表明饱和状态时,再生砖蓄留的水分是陶瓷砖的1.43倍;透水砖的吸水及保水性能并无一定关联性,故从蒸发降温角度考虑透水砖吸水特性时,应采用毛细吸水系数Aw及单面浸泡饱和质量含水率W_(sat)共同作为砖体吸水及保水性能指标;W_(sat)与透水砖开放孔隙率呈正相关关系,而Aw与透水砖开放孔隙率和孔径尺寸均有重要关联性。     

在坯料中添加生活垃圾对陶瓷透水砖性能的影响

利用破损陶瓷及废料在常规生产工艺下制造低成本、高附加值的透水砖,并探讨了生活垃圾添加量对透水砖性能的影响;提高生活垃圾添加量可以提高透水砖的抗折强度和致密度,但降低了透水砖的透水性能和吸水率。生活垃圾在砖坯中起两个相反的作用——成孔和熔剂,控制生活垃圾添加量在5%内,对陶瓷透水砖的透水性能影响不大。     

阻燃型稻草板制造工艺研究

以稻草秸秆为原料,采用正交试验设计方法,研究工艺参数(包括异氰酸酯树脂(MDI)胶黏剂、脲醛树脂(UF)胶黏剂和阻燃剂(FR)添加量)对稻草板力学性能和阻燃性能的影响,确定最佳制板工艺条件.研究表明:稻草表面碱处理对改善稻草板的胶合性能有显著作用;MDI胶黏剂添加量对稻草板弹性模量(MOE)、静曲强度(MOR)、内结合强度(IB)、2 h吸水厚度膨胀率(2 hTS)指标影响显著,而UF胶黏剂和FR添加量对该4项性能的影响较小;随着FR添加量的增加,稻草板热释放速率峰值(pk HRR)有下降趋势;最佳制板工艺条件为:MDI胶黏剂、UF胶黏剂、FR添加量分别为3%,6%,10%(质量分数).     

硅烷基防护剂对砖质材料防护性能的研究

砖质材料建筑物结构使用年限一长,会出现粉化、开裂、剥落等问题。借鉴混凝土结构防护的经验,考察了硅烷基防护剂对不同砖质材料的防护性能,探讨了防护机理,研究了硅烷基防护剂对砖质材料内部结构、吸水量比、耐酸性、耐冻融性以及表面憎水效果的影响。结果表明,硅烷基防护剂能降低砖质材料的吸水量比,提高其耐酸、耐冻融性能。     

有机改性干硬性再生混凝土的力学及吸水性能

为进一步丰富再生骨料的使用场景,该研究采用有机硅树脂溶液改性再生骨料,并分析了改性干硬性再生混凝土的力学及吸水性能。分别基于强度测试结果(抗压强度、劈裂抗拉强度)和毛细吸水试验结果评价有机改性方式对干硬性再生混凝土力学性能和吸水性能的影响。结果表明,对于未改性以及有机改性的两类干硬性再生混凝土,随着再生骨料掺量的逐步增加,虽然两类干硬性再生混凝土整体上表现出强度下降和吸水能力上升的趋势,但相同条件下,有机改性干硬性再生混凝土强度和吸水量的变化程度更小。这说明有机硅树脂溶液对干硬性再生混凝土力学及吸水性能的调节效果显著。综合强度和吸水量结果,将再生骨料掺量控制在30%以内比较合适,并且建议采用有机硅树脂对再生骨料进行改性处理。     

利用废砖粉作为矿物掺合料制备干粉砂浆的研究

利用废砖粉作为矿物掺合料分别取代10%、20%和30%水泥量制备干粉砂浆,通过对干粉砂浆的28d抗压强度、稠度、保水率和14d拉伸黏结强度等性能研究。结果表明:废砖粉具有一定的水化活性,可以作为矿物掺合料制备干粉砂浆。     

废弃黏土砖再生骨料对灌浆料性能的影响

基于废弃黏土砖的再生利用和水泥基灌浆料的基本性能要求,采用多种方式对废弃黏土砖再生骨料进行强化处理,并利用强化后的再生骨料替代灌浆料中的天然骨料,从废弃黏土砖再生骨料取代量方面开展对灌浆料工作性能和强度的影响研究。研究结果表明:采用水泥净浆包裹方法对废弃黏土砖再生骨料进行改性,当水泥净浆水灰比为0.45时,再生骨料吸水率最小为21.4%,压碎指标最小为30.9%;采用水玻璃浸泡方法对废弃黏土砖再生骨料进行改性,当水玻璃浓度为5%,浸泡时间为1 h时,再生骨料压碎指标最小为21.1%,对应的吸水率为23.0%;当水玻璃浸泡改性后的再生骨料取代天然骨料的量为10%~30%时,灌浆材料满足早期和后期强度高、工作性好、自密实、不离析等灌浆料的要求。     

废耐火砖在烧结黏土砖中的有效利用

在制砖用黏土中按所定范围内的粒径和用量掺入废耐火砖粒料来制砖,砖不仅可获得不同等级的抗压强度,特别是高抗压强度,而且达到所需的吸水率.     

Study on fired bricks with replacing clay by fly ash in high volume ratio

In present paper fly ash in wet state with low quality was used as raw material to replace clay to make fired bricks. The effect of fly ash with high replacing ratio of clay on firing parameters and properties of bricks were studied. The results indicate that the plasticity index of mixture of fly ash and clay decrease dramatically with increasing of replacing ratio of fly ash. Additive A can be chosen to improve the plasticity index of mixture to meet plastic extrusion used in most brick making factories. The sintering temperature of bricks with high replacing ratio of fly ash was about 1050 °C, which is 50–100 °C higher than that of clay bricks. The properties of fired bricks were improved by using pulverized fly ash. The fired bricks with high volume ratio of fly ash were of high compressive strength, low water absorption, no cracking due to lime, no frost and high resistance to frost-melting.     

A perspective study on fly ash–lime–gypsum bricks and hollow blocks for low cost housing development

Housing is a great problem in today's world. The most basic building material for construction of houses is the usual burnt clay brick. A significant quantity of fuel is utilized in making these bricks. Also, continuous removal of topsoil, in producing conventional bricks, creates environmental problems. A feasibility study was undertaken on the production of fly ash–lime–gypsum (FaL-G) bricks and hollow blocks to solve the problems of housing shortage and at the same time to build houses economically by utilizing industrial wastes. The compressive strength, water absorption, density and durability of these bricks and hollow blocks are investigated. It is observed that these bricks and hollow blocks have sufficient strength for their use in low cost housing development. Tests were also conducted to study the influence of type of curing on the increase in strength and hardening of the bricks and blocks with time. It was observed that the hot water curing leads to a greater degree of hardening and higher strength, earlier compared to ordinary water curing.     

成孔剂对烧结页岩砖性能的影响

选用锯末、煤矸石和造纸污泥作为烧结页岩砖的成孔剂,系统研究不同成孔剂的热解特性及其对页岩烧结砖的可塑性、体积密度、抗压强度、显孔隙率、吸水率等性能的影响。结果表明：随着锯末掺量的增加,烧结砖中孔隙数量增加,同时其体积密度和强度迅速下降,吸水率增加,因而掺量应控制在6%以内;煤矸石可塑性较差,烧失量较小,烧结页岩砖的孔隙率低,从而导致其吸水率低,体积密度和强度降低幅度都较小,实际生产中可根据内燃砖发热量和可塑性要求,适量掺加煤矸石;造纸污泥的可塑性较好,随着掺量增加混合料的可塑性变大,但掺量过大成型搅拌困难     

Geochemical contamination of urban water by concrete stormwater infrastructure: applying an epoxy resin coating as a control treatment

Urban drainage systems that use concrete gutters, pits and pipes have been adopted worldwide by drainage engineers. This study tested the hypothesis that treating a concrete pipe with a coating of epoxy resin is an effective method to reduce the concrete mineral leaching and associated contamination of water carried within the pipe. Four 20 litre samples of rainwater were individually circulated through the untreated and epoxy treated portions of the pipe for 100 minutes. After recirculation through the untreated portion of the pipe pH increased by almost two units, electrical conductivity doubled and there were significant increases in bicarbonate, calcium and other ions. In contrast, rainwater circulated through the epoxy treated portion of the pipe showed a minimal pH increase (0.32 pH units) but no other significant increases in any other water chemistry attributes. The epoxy resin greatly reduced mineral contamination of recirculated water, supporting the hypothesis.     

简单屋顶绿化的滞蓄特性

设计了模拟降雨与数据采集系统,研究了短时强降雨下简单屋顶绿化基质（配比：陶粒57．0％、草炭41．5％、保水剂1．5％）的降雨产流过程,基于37次模拟降雨实验,归纳了降雨产流的一般过程、规律和特性,分析了降雨强度、基质厚度和基质初始含水率对简单屋顶绿化滞流蓄水特性的影响。结果表明：基质厚度和基质初始含水率对简单屋顶绿化的蓄水特性有显著影响,基质初始含水率越低、基质厚度越厚时蓄水特性越佳。建立了产流时间数学模型,简单屋顶绿化降雨产流时间与降雨强度呈负相关,同时也受初始含水量和基质厚度影响。随着干湿循环次数增加,基质的厚度总体呈现下降趋势,储水性能逐渐下降,延迟产流时间逐渐缩短。     

吸水率对蒸压粉煤灰砖耐水性的影响

通过不同含水率和不同吸水率蒸压粉煤灰砖的抗压强度和抗折强度试验,分析了含水率与吸水率对蒸压粉煤灰砖的抗压强度和抗折强度的影响,并与美国规范进行比较,为我国标准中的抗压强度试件的含水率要求和砖的最大吸水率提出了建议。     

污水污泥烧结页岩砖性能试验研究

本实验将高含水率污水污泥与来源广泛的页岩进行混合,在固定污泥掺量,变化烧成温度、升温速率和保温时间等因素的基础上进行实心和多孔污泥页岩烧结砖的烧制。结果表明,污泥掺量30%时可以烧制出体积密度1600 kg/m3左右,抗压强度10MPa以上的实心砖,在此基础上对污水污泥对烧结砖的性能影响进行了实验研究。     

The potentials of lateritic soil—Clay and clay-sand mixes in the manufacturing of bricks for masonry units

Bricks were manufactured from lateritic soil-clay and clay-sand mixes with various mix proportions; 30, 40, 50, and 60% sand (by weight) were mixed with clay soil, 20 and 40% clay (by weight) were mixed with lateritic soil. The bricks were burnt at 1000°C for periods of 2, 4 and 6 h. Various properties of the bricks such as linear shrinkage, density, compressive strength and water absorption were measured. Test results showed that the addition of 40% clay in lateritic soil was the optimum for the production of bricks from lateritic soil. The addition of 30% sand in clay was optimum for the production of bricks from clay. The compressive strength of the investigated bricks was also compared with British starutory requirements for the minimum compressive strengths in bricks for various walls. The comparison showed that both lateritic soil-clay and clay-sand mixed bricks could be used in load bearing walls.