道路面层用建筑垃圾再生混凝土配合比设计分析

通过废混凝土骨料和废砖骨料按比例混合模拟建筑垃圾的组成,制成建筑垃圾再生混凝土,在分析废砖骨料掺量、附加水用量和颗粒级配等对再生混凝土性能影响的基础上,研究道路面层建筑垃圾再生混凝土配合比设计方法.结果表明:建筑垃圾再生混凝土抗折强度随水灰比的增大而降低,随附加水用量的增大而降低;当再生粗骨料中掺25％砖骨料时,建筑垃圾再生混凝土基本力学性能满足新建水泥路面面层材料的要求,而当掺量达50％时,对再生混凝土抗折强度影响较大;颗粒级配的影响较小;用本文的计算公式得到的再生混凝土抗折强度计算值与实测值很接近.     

再生混凝土透水砖试验研究*

针对建筑垃圾的处理的问题,提出了将废弃混凝土破碎、清洗、分级处理成再生骨料,采用正交试验方法用这种骨料制备透水砖,同时,考虑了粒径、水泥用量、砂率及水灰比等因影因素对透水砖性能的影响。研究结果表明,当骨料粒径为10-20 m,水泥用量为420 kg/m³,砂率为9%,水灰比为0.31时,满足再生混凝土透水砖的标准要求;分别建立了粒径、水泥用量、砂率及水灰比等影响因素与透水系数、抗压强度的回归方程;最后,建立了透水系数与抗压强度的二次曲线拟合方程。     

砖砼混合再生粗骨料混凝土力学性能研究

随着我国城市规模的不断扩大,大批既有建筑面临拆迁,由此产生的建筑垃圾体量巨大,对废弃建筑垃圾进行回收利用不仅是时代所需,并且对于保护环境、节约资源、发展生态建筑具有重要意义.通过试验,研究分析了不同体积比的砖砼混合再生骨料混凝土的力学性能.结果表明:(1)对于砖砼混合再生骨料混凝土而言,再生砖骨料占比越大,混凝土强度降幅越大,再生砖骨料占比对混凝土抗压强度和劈裂抗拉强度的影响更为显著.(2)再生砖骨料占比为30％和50％时,再生混凝土的28 d抗折强度分别为4.7 MPa和4.5 MPa,已接近水泥混凝土道路相关规范要求,如采取有效技术手段对再生骨料或再生混凝土进行增强,有望使砖砼混合再生骨料混凝土用于道路工程的面层.(3)混凝土抗折强度与抗压强度符合良好的二次函数关系,混凝土劈裂强度与抗压强度符合良好的幂函数关系,混凝土劈裂强度与抗折强度符合良好的指数函数关系.     

再生混凝土多孔砖砌体轴心抗压强度试验

制作再生混凝土骨料替代率为75%、抗压强度达到MU10的再生混凝土多孔砖。对18个再生混凝土多孔砖砌体试件在轴心荷载作用下的试验进行研究。考察再生混凝土多孔砖砌体在不同砂浆强度下的受压性能和极限承载力,分析砌体的受压变形过程和破坏特征。结果表明:再生混凝土多孔砖砌体的受压性能和普通混凝土多孔砖砌体的受压性能基本相似,极限状态时多孔砖砌体被贯通的竖向裂缝分隔成若干独立小立柱,小立柱被压坏,再生混凝土多孔砖砌体轴心抗压强度略小于普通混凝土多孔砖砌体。通过对试验数据的分析,参考现行《砌体结构设计规范》建议的公式,提出了再生混凝土多孔砖砌体的轴心抗压强度计算公式。     

西安市建筑垃圾的基本性质研究

本文借助X射线荧光光谱仪、X射线衍射分析、扫描电子显微镜、易磨性和力学性能测试等分析手段对从西安市两个不同城区拆迁工地所取废砖,废混凝土的化学组成、矿物组成、易磨性和活性等基本性质做了系统分析研究.结果表明:(1)从不同城区所取建筑垃圾的化学组成和矿物组成差异较大,要实现建筑垃圾的有效利用需做好原料的均化;(2)较之水泥熟料,废砖和废混凝土的易磨性较好,但废砖比废混凝土要更易磨.300 ～400℃的低温热处理可进一步改善废混凝土的易磨性;(3)废砖粉中所含的SiO2和Al2 O3具有一定的活性.在大掺量下(30％),掺入废砖粉的试样抗压强度比掺入相同掺量废混凝土粉试样的强度降低要少.     

石膏基保温砂浆的制备与性能研究

试验研究了普通硅酸盐水泥、硫铝酸盐水泥、矿粉三种胶凝材料以及保温骨料玻化微珠和功能组分对石膏基保温砂浆性能的影响。通过研究表明：掺入硫铝酸盐水泥可以显著提高石膏基保温砂浆的力学性能;当玻化微珠与复合胶凝材料质量比为5:10、纤维素醚为0.2%、引气剂为0.005%时,石膏基保温砂浆的导热系数为0.08 W/(m·K)、强度为1.0 MPa、体积密度为370 kg/m³,同时砂浆的和易性、可批刮性也满足施工要求。     

建筑垃圾再生微粉对泡沫混凝土性能的影响

文章就建筑垃圾生产再生骨料产生的细粉(粒径0.15 mm)经过合理的粉磨处理制得再生微粉,将再生微粉替代10%～60%的普通硅酸盐水泥制备泡沫混凝土,探索再生微粉对泡沫混凝土干密度、吸水率和抗压强度的影响。试验结果表明,再生微粉可替代部分水泥制备A04密度等级的泡沫混凝土,替代量不同,泡沫混凝土的性能差异较大。     

改性聚苯板外墙外保温系统的隔热性能分析

合理的建筑外墙外保温系统可以有效的降低能源消耗、保护环境。基于此,设计了改性聚苯板外墙外保温系统,建立了外墙外保温系统的计算模型,拟定夏季热雨和冬季供暖两种工况,对比分析了改性聚苯板、普通水泥砂浆和玻化微珠混凝土三种不同外墙外保温系统的隔热性能。研究结果表明:改性聚苯板外墙外保温系统的隔热性优于普通水泥砂浆和玻化微珠混凝土外墙外保温系统;在夏天热雨外部温度最高时,改性聚苯板保温层内表面的温度要比玻化微珠混凝土和普通水泥砂浆小约65%,外表面的温度则要高约27%;在同样的冬季室内外温差条件下满足室内供暖标准,改性聚苯板外墙外保温系统的能耗量比玻化微珠保温系统减小73.7%,比普通砂浆保温系统减小77.0%。     

一种双组分聚合物保温砂浆涂层的研制

以玻化微珠或闭孔珍珠岩制成的保温轻骨料的无机保温砂浆是一种新型建筑干粉砂浆。具有保温隔热及耐火、耐老化性能较好的特点。本文试制一种以硅酸盐水泥、粉煤灰、氢氧化钙、纤维、纤维素醚和乳胶粉为一个组份,以玻化微珠为保温轻骨料作为另一个组份,来研制无机轻骨料聚合物保温砂浆。讨论双组份之间比例对保温砂浆的性能影响进行对比分析,获得了较佳双组份聚合物保温砂浆组成。     

再生骨料在混凝土路面砖中的应用研究

文章将建筑垃圾中的混凝土和红砖破碎形成的再生骨料,按不同比例替代路面砖中的天然骨料,研究了再生骨料替代比例对路面砖强度的影响以及路面砖的生产制备工艺对再生路面砖强度的影响。结果显示再生混凝土砂的掺加有利于再生混凝土路面砖抗压强度提高,而红砖砂的掺加则会降低再生混凝土路面砖的强度,路面砖的生产工艺及混凝土配比对混凝土路面砖强度有较大的影响,半湿法工艺可大大提高路面砖抗压强度。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。