高黏改性沥青高温黏弹特性指标区分度分析

为得到能准确区分高黏改性沥青高温性能的评价指标,分别对3种高黏改性沥青(高黏改性剂掺量均为12%)及基质沥青进行滞后环、动态剪切流变(DSR)和软化点等试验,并采用沥青混合料车辙试验进行了验证,基于沥青混合料试验结果对3种高黏改性沥青的高温性能评价指标作了一致性和区分度分析.结果表明:3种高黏改性剂的掺入均可提高基质沥青的黏弹特性和高温性能,但改性效果不同;不同高温评价指标基本能对3种高黏改性沥青的高温性能做出一致性评价,但区分能力不同,其中滞后环试验技术指标和Carreau模型拟合的零剪切黏度(ZSV)值区分度和评价效果最好,而车辙因子和软化点较差.     

复合改性沥青混合料组成及性能研究

选用车辙试验、单轴贯入试验及小梁弯拉疲劳试验,进行了重载长效路面复合改性沥青混合料组成及性能研究.车辙试验和单轴贯入试验结果表明,掺加抗车辙添加剂PR.S不仅能提高普通沥青混合料的高温性能,对于改性沥青混合料同样具有显著效果.PR.S掺量为0.4%和0.6%（质量分数,下同）的沥青混合料其高温性能差异并不显著,说明就经济性而言,PR.S掺量可以选择为0.4%.小梁弯拉疲劳试验结果表明,掺加纤维及PR.S均能有效提高改性沥青混合料的疲劳性能.研究得到的复合改性沥青混合料（SUP-19＋泰普克改性沥青＋0.4%PR.S）具有良好的高温性能和疲劳性能,能满足重载长效路面对沥青混合料组成的要求.     

SMA沥青混合料均匀性和路用性能研究

选用木质素纤维、矿物棉纤维和短切矿物纤维,通过室内试验,对比分析了掺加以上三种不同纤维的SMA沥青混合料的均匀性及路用性能,对比试验结果表明:掺加矿物棉纤维和木质素纤维后,SMA混合料表现出良好的均匀性;掺加短切矿物纤维的SMA混合料的高温稳定性能较好,水稳性能较差;纤维沥青混合料的均匀性在一定程度上影响其路用性能。     

聚丙烯腈纤维及抗车辙剂在SMA混合料中的应用

文章介绍了聚丙烯腈纤维及抗车辙剂的性能作用，对掺加聚丙烯腈纤维及抗车辙剂的SBS改性沥青SMA混合料性质进行路用性能研究。     

基于配伍性分析的高掺量橡胶沥青路用性能研究

为了制备具有高存储稳定性的高掺量橡胶沥青,基于配伍性研究,通过离析指标和PG分级试验,研究胶粉掺量对改性沥青性能影响.并通过水稳定性试验和高温车辙试验,评价高掺量橡胶沥青路用性能.研究表明:高掺量橡胶沥青在存储早期(24 h内)的177℃黏度有一定程度的下降,存储中后期(24 h后)177℃黏度趋于稳定,具有良好的储存...     

复合式SMA桥面铺装混合料配比设计及高温抗车辙性能研究

为了提升桥面铺装的高温抗车辙性能,采用马歇尔配合比设计方法对3种SMA沥青混合料分别进行级配设计及体积指标验证,选用轮辙试验和车辙试验对所设计的5种复合式SMA桥面铺装结构组合的高温性能评价指标进行测试.结果表明,SMA混合料沥青析漏损失及飞散损失均满足技术要求,SMA具有合理的最大沥青用量,且粘附性良好;提出的5种复...     

抗车辙剂和纤维对沥青混合料性能的影响分析

通过对沥青混合料的各项性能进行试验,分析掺加了抗车辙剂和纤维的沥青混合料的路用性能,特别是高温稳定性和低温抗裂性,得到了抗车辙剂和纤维对沥青混合料高低温稳定性和水稳定性的影响规律,同时也确定了适合于掺加抗车辙剂和纤维的沥青混合料的最佳油石比。     

纤维对SMA路用性能的影响研究

以SMA-16为例,通过水稳定性、高温稳定性、疲劳性能三个方面的试验评价不同纤维对SMA路用性能的影响。水稳定试验表明,三种纤维的水稳定性性能相差不大;车辙试验表明,玄武岩矿物纤维相对其他两种纤维来说,对SMA的高温性能改善较大;四点弯曲疲劳实验表明,聚丙烯腈纤维更多的增加了SMA的疲劳寿命。     

LDPE与DOP复合改性沥青及其混合料性能研究

为了改善低密度聚乙烯(LDPE)改性沥青的低温性能,将增塑剂(DOP)掺入LDPE改性沥青对其进行增塑。通过不同改性剂掺量下的沥青性能试验确定了LDPE与DOP合适的掺量范围,通过高温车辙、低温小梁弯曲、浸水马歇尔、冻融劈裂试验评价了沥青混合料的路用性能。试验结果表明:LDPE与DOP复配后,复合改性沥青的低温延展性得到明显提升,感温性能与抗老化性能也有一定改善;改性沥青混合料的低温抗裂性大幅度改善,同时也具有良好的高温稳定性和水稳定性能。     

抗车辙剂与玄武岩纤维复合改性沥青混合料及性能研究

将玄武岩纤维与抗车辙剂RA进行复配,对沥青混合料进行改性。分析了抗车辙剂和玄武岩纤维掺量对复合改性沥青混合料高低温性能、水稳定性和抗疲劳性能的影响,并与5%SBS改性沥青混合料进行对比。结果表明,掺加抗车辙剂RA能显著改善沥青混合料的高温稳定性和水稳定性,掺加玄武岩纤维能大幅度提高抗车辙剂RA改性沥青混合料的低温抗裂性能和抗疲劳耐久性能。推荐采用0.4%RA与0.35%玄武岩纤维复配方案,该复合改性沥青混合料的力学性能、路用性能与抗疲劳耐久性能优于5%SBS改性沥青混合料。     

Rate constants of reactions of ozone with organic and inorganic compounds in water—III. Inorganic compounds and radicals

Second-order rate constants for reactions of ozone with 40 inorganic aqueous solutes are reported. Included are compounds of sulfur (e.g. H₂S, H₂SO₃, HOCH₂SO₃H), chlorine (e.g. Cl⁻, HOCl, NH₂Cl, HClO₂, ClO₂), bromine (e.g. Br⁻, HOBr), nitrogen (e.g. NH₃, NH₂OH, N₂O, HNO₂) and oxygen (e.g. H₂O₂), as well as free radicals (e.g. O₂⁻, OH^•). Most of these compounds exhibit an increase in rate constant with increasing pH corresponding to their degree of dissociation. Rate constants are based on ozone consumption rates measured by conventional batch-type or continuous-flow methods (10⁻³-10⁺⁶ M⁻¹ s⁻¹ range) and determinations of stoichiometric factors. Also listed are data determined by pulse-irradiation techniques using kinetic spectroscopy (10¹⁰ M⁻¹ s⁻¹ range). Additional literature data are reviewed for completeness. Results are discussed with respect to water treatment and environmental processes.     

Formation of disinfection by-products in indoor swimming pool water: the contribution from filling water natural organic matter and swimmer body fluids

The contribution and role of different precursors in the formation of three class of disinfection by-products (DBPs) [trihalomethanes (THMs), haloacetic acids (HAAs), and halonitromethanes (HNMs)] in swimming pool waters were examined using filling waters obtained from five drinking water treatment plant (WTP) effluents and three body fluid analogs (BFAs). BFAs exerted higher chlorine demands as compared to natural organic matter (NOM) in filling waters. BFAs exhibited higher HAA formation potentials than THM formation potentials, while the opposite was observed for the filling water NOM. There was no appreciable difference in the HNM formation potentials of BFAs and filling water NOM. Different components in the BFAs tested exhibited different degree and type of DBP formation. Citric acid had significantly higher THM and HAA yields than other BFA components. The effect of temperature was greater on THM formation, whereas the effect of contact time had more impact on HAA formation. Experiments with filling waters collected from WTP effluents at three different times showed more variability in HAA than THM formation at the WTPs studied.     

建筑西向房间夏季室内热环境改善

以国内某大学综合实验大楼为例,实测了其中一间西向房间的室内外空气温度与壁面温度,分析了其夏季室内热环境。为了在经济合理地使用能源的情况下,满足它对夏季冷量与冬季热量的需求,根据实测的数据,利用建筑热平衡原理,对其夏季室内热环境特性进行了分析,指出了其热工设计缺陷,并对其进行了热舒适性的改造。通过软件模拟出改造后房间室内空气温度值,对比改造前后室内空气温度值,结果显示改造后的温度值明显降低,热舒适性得到了改善。     

Behavior of alkylphenol polyethoxylate metabolites during soil aquifer treatment

The attenuation of alkylphenol polyethoxylates (APEOs) metabolites was studied at a soil aquifer treatment (SAT) site located in Arizona, USA. Two parcels of water were monitored during infiltration; one parcel was predominantly oxic while the other was predominantly anoxic. In this study, only alkylphenol ethoxycarboxylates (APECs) and carboxyalkylphenol ethoxycarboxylates (CAPECs) were detected, no short-chained APEOs were observed-even under anoxic conditions. APEO metabolites were rapidly (<7 days) removed under both aerobic and anoxic conditions. In general, the length of the ethoxycarboxylate chain decreases with depth--at depths greater than 3m, only alkylphenoxy acetic acids (AP1ECs), carboxyalkylphenoxy acetic acids (CAP1ECs), and alkylphenols (APs) remain. Under aerobic conditions, octylphenol and nonylphenol concentrations decreased by approximately 80% (w/w) within 3m of the ground surface. Under anoxic conditions however, alkylphenol concentrations increased by approximately 200% during the first 1.5m and then decreased during the next 1.5m; overall, under anoxic conditions, alkylphenol concentrations increased by approximately 38% within 3m. During infiltration, APEC and CAPEC concentrations decrease by more than 95% within 3m of SAT. Alternate flooding and drying cycles appear to enhance overall APEO metabolite removal efficiencies.     

膨润土对重金属离子Pb~(2+),Zn~(2+),Cr(VI),Cd~(2+)的吸附性能

试验研究了pH值、吸附时间和吸附剂用量对膨润土吸附重金属离子Pb2 ,Zn2 ,Cr(VI)和Cd2 的影响.结果表明,在本试验的pH值、吸附时间及吸附剂用量条件下,膨润土对Pb2 ,Zn2 ,Cd2 的吸附效果均优于其对Cr(VI)的吸附效果;pH值是影响上述吸附的重要因素,离子交换和表面络合是上述吸附的主要形式.     

沥青混合料动态蠕变模量与动稳定度的关系

研究了分别基于AC13和AC25优化出的9组级配、SBS改性中海70#沥青和中海70#沥青两种结合料、花岗岩和石灰岩两种集料以及50,70 mm两种车辙试件厚度等条件下的沥青混合料动稳定度(DS)与车辙模量(E_(DS)),E_(DS)与动态蠕变劲度模量(S_(dy)),S_(dy)与DS这三者的关系.结果表明,不同沥青混合料的S_(dy)与采用厚度匹配的车辙试件DS之间存在良好的相关性.因此可以将DS转换为S_(dy),并用其作为沥青路面结构设计的参数.     

小剪跨比钢筋混凝土实腹支托的受力性能及非线性全过程分析

本文用非线性全过程分析和足尺试件的破损试验的方法对工业建筑结构中常用的小剪跨比钢筋混凝土支托进行力学性能的讨论。文章提出了小剪跨比支托不同于一般支托的力学特性和破坏机理,认为“剪摩理论”对于小剪跨比支托的适用性是存在的。     

Removal of VUV pre-treated natural organic matter by biologically activated carbon columns

A potential alternative water treatment process using VUV (185 nm+254 nm) irradiation followed by a biological treatment is described. The system uses sufficient VUV radiation (16J cm(-2)) to significantly enhance the production of biologically degradable moieties prior to treatment with biologically activated carbon (BAC). Two similar activated carbons were used, one virgin and one taken from a water treatment plant with an established biofilm. The VUV-BAC process decreased the overall dissolved organic carbon (DOC) concentration of a natural water sample by 54% and 44% for the virgin carbon and previously used BAC, respectively. Furthermore, VUV-BAC treatment decreased the trihalomethane (THM) formation potential (THMFP) by 60-70% and the haloacetic acid (HAA) formation potential (HAAFP) by 74%. The BAC systems effectively removed the hydrogen peroxide residual produced by VUV irradiation. Although nitrite formation can result from VUV treatment of natural organic matter (NOM), none was detected before or after BAC treatment.     

A modification of the Trent Index for use in Denmark

A new pollution index based on macroinvertebrates has been devised which can be used as a surveillance system in Danish streams. The index is inspired by the Trent Index although it was necessary to incorporate two new principles. First, the pollution indicators Asellus aquaticus and Chironomus sp. are used as negative taxa, with a negative influence on the index value, thereby strongly enhancing the utility of the keygroups. Secondly, the taxonomic groups used in the Trent Index have been replaced by establishing positive and negative index groups, where the number of negative index groups is subtracted from the number of positive. Thus, the utility of the basic principle, increasing pollution effecting decreasing numbers of taxonomic groups, is enhanced.     

750kV GIS中金属氧化物避雷器对VFTO影响的研究

随着超高压气体绝缘变电站(GIS)的广泛使用,由隔离开关(DS)和断路器(CB)操作引起的快速暂态过电压(VFTO)的危害越加明显。以西北地区750 kV官亭GIS变电站为计算原型,利用电磁暂态程序(EMTP)对不同运行方式下GIS设备上的VFTO进行数值仿真计算和分析。重点在于对不同运行方式下金属氧化物避雷器(MOA)的限制过电压效果进行分析。计算结果表明:DS无分合闸电阻时,MOA防护效果更明显;MOA主要的抑制效果体现在MOA附近的设备上,对于远离MOA的设备上的VFTO的抑制效果较小;由于VFTO持续的时间极短,通过MOA的能量很小。