Characteristics of Asphalt Rubber Mortar and Aggregate Gradation Optimization Based on High Temperature Condition

To improve the performance of asphalt rubber mixture under high temperature, an optimal proposal was put forward which selected asphalt rubber mortar and aggregate gradation as the main objects. According to experimental tests, the anti rutting factors and phase angles of asphalt mortar was studied with different rations of filler bitumen. And then, with the characteristics of asphalt rubber, the optimal gradation was presented by means of the adjustment of aggregate gradation which chose dynamic stability and relative deformation as value indexes. The results shew that asphalt rubber mixtures would show an optimal high temperature performance if the following measures can be taken: (1) making an adjustment of ratio of filler bitumen to about 1.2; (2) replacing mineral powder with cement; (3) making an adjustment of aggregate gradation and lower the proportion of mineral powder based on SMA.     

Index of Factors Influencing the Shear Strength of Asphalt Mixtures

Asphalt mixtures with high shear strength have great capability to resist perpetual deformation under high temperatures. We used a single penetration test to analyze the material design indexes for high performance asphalt mixtures. The test results show that the performance of the asphalt binder and the performance of the coarse aggregate, especially the fine aggregate, greatly affect the shear strength of asphalt mixtures. We also suggest that the coarse aggregate with a high aggregate particle index, fine aggregate with high angularity, and asphalt with high viscosity can increase sharply the shear strength of an asphalt mixture. Furthermore, the degree of compaction of an asphalt mixture should be controlled to guarantee excellent long term performance of asphalt pavement.     

Research on BRA Asphalt Mixture Pavement Performance Based on Containing BRA Rock

AH-70 road asphalt as the basis, Buton rock asphalt mixture pavement performance was studied by using six different Buton rock asphalt adding quality and six different AC20 aggregate gradation. The results show that Buton rock asphalt raw materials including the rock mineral significantly affects aggregate gradation and the pavement performance; reasonable choice OAC can significantly improve the road performance, and the road performance in the condition of 0.7%~1.3% optimum OAC is close to that of the SBS modified asphalt mixture, but Buton rock asphalt improving the water stability is limited; Buton rock asphalt optimum dosage is 23.7%, and Buton rock asphalt OAC and OAC of Buton rock asphalt raw material is almost the same.     

Rut resistance Properties of a Large stone Flexible Base under Heavy Loads

The rut resistance properties of large stone flexible bases are studied, taking into consideration heavy loads and using computer simulation and numerous indoor tests. In computer simulations of large stone flexible bases, a calculation method was formulated for predicting asphalt pavement rut under dynamic loads. The method was based on the coupling of vehicle dynamic loads and pavement surface unevenness. The results of indoor testing and three dimensional numeric calculation under dynamic loads are confirmed by tracking observation results of a test road. We conclude that the rut resistance properties of large stone flexible base asphalt pavement built using low grade asphalt and low crush value high performance aggregate with reasonable gradation is no worse than that of the semirigid base asphalt pavement, and that ruts mainly are caused by the lateral shear.     

Structure and Performance of the Interface Zone between Mortar and Aggregate in Cement Concrete

The interface zone between mortar and aggregate influences overall performance of concrete and is an important issue for concrete research. Focusing on the structure and performance characteristics of the interface zone in cement concrete, the development of interface research in P. R. China and elsewhere were reviewed. The research aspects discussed included interface structure and performance, study techniques, interface improvement methods, and the influence of the interface on overall concrete performance. The influential factors of structural characteristics and interface zone performance, together with both microscopic and macroscopic research techniques, were summarized. The reasons for differences in interface zone structure and performance, and its degree of influence on the overall concrete performance were analyzed. Methods for improving the interface zone were generalized, including using an interface with slag powder as inorganic material and one with an organic coupling agent. Keys to research and future directions were proposed.     

Study on Influence of Fiber to Stability of Asphalt Concrete Pavement

The effect of fiber in asphalt mixtures has attracted general concern. For study of this problem, four kinds of fibers are chosen in this test. Asphalt and modified asphalt are adopted in asphalt mixtures AC-16I. The road performance influenced by additional fiber was analyzed impersonally,i, e. the stability of asphalt concrete under high temperature condition, anti-crack ability under low temperature condition, the water resistance and fatigue performance. It was shown through the research that the optimum asphalt content, air void rate, clearance rate of the mineral powder, saturation degree, and the flow value were increased and the density was decreased after adding the fiber. The road performance, such as the stability of asphalt concrete under high temperature condition, anti-crack ability under low temperature condition, water resistance and fatigue performance, was obviously improved,and the high temperature stability and fatigue performance improved most evidently. The fiber asphalt mixture performance reached and even exceeded the modified asphalt mixture performance. The modified asphalt performance after adding fiber would be improved more greatly.     

Experiment And Study On Microstructure of Superfine- sand High Strength Concretes

A high strength concrete with 28 day strength up to 80 MPa from superfine sand with fineness modulus of 0.56 is obtained.It has a permeability resistance of 4.0 MPa and small shrinkage creep.Experiment and study were carried out on its pore structure,hydration products and microhardness of transient area in cement paste and aggregate interface. The essence for high strength of such concrete was revealed.     

Effects of Stone Powder on Wet Packing Density of Cement and Performances of Concrete

The amount of limestone powder, which is a by product of manufactured fine aggregate, is larger and larger with the increase of manufactured fine aggregate. Environment will be severely polluted if the powder is improperly used. The effects of limestone powder on workability, compressive strength, and impermeability of concrete were studied when cement is substituted for the mass proportion of 0, 10, 15, 20 percent with it. The results show that the performances of concrete are better improved when the percentage of limestone powder is about 10 percent. The wet packing density of mixture of limestone powder and cement was measured, and it shows that the degree of density was biggest when limestone powder is 10 percent. This shows that the best mixing proportion of limestone powder and cement may be determined through measuring the change of compactness of mixture of limestone powder and cement.     

不同基质配比对边坡修复植物生长的影响研究

采用盆栽试验的方法,以典型的边坡绿化植物早熟禾(Poa annua)为供试材料,水泥、保水剂、肥料和腐殖质为基质原材料,选用L9(34)正交表进行试验,对比研究在4种基质原材料的9种不同配比下早熟禾生长状况的差异性,并对9种配比基质的物理性质、化学性质、植物出芽率、植物存活率及50天植物株高等指标进行测定与分析。结果表明,不同基质配比对早熟禾的生长状况影响不同。通过极差分析得出,4个因素对植物出芽率影响的主次顺序为：保水剂>腐殖质>水泥>肥料;对植物存活率影响的主次顺序为：保水剂>水泥>肥料>腐殖质;对50天植物株高影响的主次顺序为：保水剂>肥料>腐殖质>水泥。最终,水泥含量15.0%、保水剂含量1.0%、肥料含量6.0%和腐殖质含量6.0%的基质,能显著增大植物出芽率及存活率,促进植物生长,是最优基质配比。而水泥含量10.0%、保水剂含量0.5%、肥料含量9.0%和腐殖质含量6.0%的基质可保证较高的植物存活率及50天植物株高。     

Asphalt pavement structure design of expressway on soft soil foundation

Non homogenous settlement will occur while the expressway is constructed on soft ground. The differential settlement can cause the bigger additional stress inside the asphalt pavement structure accelerating bituminous pavement destruction. Therefore,we must choose reasonable pavement structure when constructing road on soft base in order to reduce the influence on surface layer structure from the differential settlement. Based on ABAQUS finite element method and through analysis, this article draws the conclusion that establishing unbound graded aggregate sandwich structure under the asphalt pavement structure can effectively reduce the horizontal additional stress of the stress controled layer and better prevent crack reflection which is beneficial for constructing the asphalt pavement structure on the soft ground.     

Investigation on EPS Surface Modification and EPS Thermal Insulation Mortar''s Weather-resisting and Crack-resisting

The surface of EPS is of hydrophobic nature, which can not wet binding material. As in the freshly mixed mortar, EPS particle is not affined with cement paste and has a low bulk density, which will be apt to make EPS particle buoy, and lead to the segregation of mortar, the decrease of water retentivity and affect its workability. When pretreated, the surface of EPS can be changed into that of hydrophilic nature, and be wetted by freshly mixed silicate paste. The technology channel of EPS surface modification is that select proper high-molecular binder and coupling agent, prepare polymer silicate binding material of low water-cement ratio, and utilize the double effect of binder and coupling agent to form silicate grout of hydrophilic nature on the surface of EPS, by composite binding material wrapping the surface of EPS. A new thermal insulating mortar with good properties of thermal engineering, weather-resisting and crack-resisting can be made by modified EPS as light aggregate and cement as binder, modification with fiber and polymer. This new type of insulating mortar can be used as outer thermal insulation of outside wall, which breaks the limitation of traditional insulating mortar only as interior insulation. It has been widely used in the building energy-saving model project.     

Cementation Effect with Cement during Cold In Place Recycling System of Asphalt Pavement

Different kinds of structures of RAP and different contents of cement were prepared. By means of standard compaction test, unconfined compressive strength, water stability, modulus and SEM test, the cementation effect with cement was studied. It was shown that the maximum dry density of RAP mixture rose from 1.91g/cm3 to 2.00g/cm3 with the increase of cement content when A/S was 0.4. The maximum dry density of RAP mixture would rise when adding more asphalt. The unconfined compressive strength rose from 1.48MPa to 2.63 MPa and then down to 2.28MPa when cement content was 6%. The best property could be got when A/S was 0.4 and the cement content was 6% with 9.5% water. The compressive strength of RAP mixture declined after it was cured in water for 24 h, but it had the same tendency with those of which had not been maintained in water. And it is also found that RAP does not obtain better stabilities in high temperature with modular test. From SEM test, it is shown that ettringite and C S H interlace and form the netted structure, and the aggregate would be enwrapped to increase the strength.     

Index System of Sub-Microstructure Analysis System of Asphalt Concrete(MASAC)

Based on the study of image processing algorithm,the Sub-Microstructure Analysis System of Asphalt Concrete(MASAC) suitable for Windows Operating System was specially programmed.In this paper the index system of MASAC is chiefly illustrated and the functions of a part of indexes are briefly introduced.The index system is classified into 5 types,i.e.characteristics of aggregate particles,arrangement of aggregate particles,contact among aggregate particles,air voids between aggregate particles and distribution of aggregate particles.By analysis for the microstructure of asphalt concrete,it can be used to investigate the internal relationship between asphalt concrete microstructure and macro-performance,and evaluate the asphalt mixture homogeneity.     

Influence of Electrochemical Chloride Extraction on the Microstructure of Desalinated Pastes of Concrete

A set of installation is designed for electrochemical chloride extracting circularly on reinforced concrete.The removal efficiency is discussed using saturated Ca(OH)2 solution,saturated Ca(OH)2 0.001 mol/L Li2B4O7 solution and distilled water as electrolyte,respectively.And the microstructure of cement paste is analyzed by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).The results prove that using saturated Ca(OH)2 0.001 mol/L Li2B4O7 solution as electrolyte is more favorable to removing chloride in concrete.Treated by electrochemical desalination,the hydrated product C-S-H resolves and Ca(OH)2 in the concrete increases,too.It deposites on the wall of pores and fills in pores,and then causes the porosity to decrease,while the ratio of Ca /Si of C-S-H increases in the interface between the steel and the concrete.     

苏州中国花卉植物园温湿效应及其对人体舒适度的影响

探讨苏州城市景观公园不同群落温湿效应及其对人体舒适感的影响,为公园内部绿地系统的布局和植物种植规划提供参考。以苏州市中国花卉植物园园外道路和园内的道路、香樟林、栀子花林、槐树林、复合林6种不同样地为研究对象,测量分析各样地温湿度变化以及对人体舒适度的影响。结果表明：将园外沥青道路作为对照,在降温强度方面,园内不同样地的降温幅度0~4.2℃,依次为乔草>乔灌草>灌草>园内沥青道路;在增湿强度方面,园内不同样地的增湿幅度0~11.7%,香樟林、槐树林、复合林在白天的增湿效果十分明显。在不同季节,整个植物园相比于园外沥青道路有降温增湿的作用,人体舒适感增加,为人们户外活动提供了一个良好的选择。今后在公园的经营管理过程中,在植物配植方面,可以考虑以乔木为主体,选择单一或复合混交结构,合理建设游憩林等林下休闲场所,以最大限度改善生态环境,吸引更多游客。     

Preliminary Discussion on Mixing Design of Porous Concrete

Porous concrete is an eco-concrete with high porosity and high strength,whose application was restricted to some extent,because there is lack of appropriate and unitive mixing design method.According to the features of porous concrete,proportion design idea of porous concrete whose major design parameter was porosity and strength was satisfied by changing variety of cementing material and aggregate size.The design method of porous concrete was that the raw materials were selected according to design requirement at first,secondly,aggregate dosage per unit volume of porous concrete was calculated,thirdly,dosage of cementing material was calculated by apparent density of aggregate and porosity of design requirement,finally,cement dosage of the unit physical volume and water dosage were calculated by water cement ratio deter mined by requirement of forming process.The test result indicated that this mixing design method of porous concrete was reliable and feasible.     

冻融损伤对再生混凝土耐久性及与钢筋粘结性能分析

制作掺入引气剂和未掺入引气剂的100%粗骨料取代率的再生混凝土RC1和RC2两组试件以及掺入引气剂和未掺入引气剂的普通混凝土NC1和NC2两组试件,并分别对经过不同次数冻融循环试件的抗压强度、质量损失率、动弹性模量损失率进行研究。结果表明,冻融后各组试件的抗压强度、质量损失率及动弹性模量损失率均降低,对于添加引气剂的NC1和RC1两组试件损失较小,其中RC1组试件在200次冻融后抗压强度损失接近40%,质量损失率达0.5%,动弹性模量损失率38.5%。100%取代率并加入引气剂的ZRC组试件冻融后进行中心拨出实验,发生劈裂破坏和钢筋拔出破坏2种形式。再生粗骨料混凝土与钢筋的极限粘结应力均随冻融次数的增加而降低,200次冻融后极限粘结应力下降33.5,荷载滑移曲线既有上升段也有下降段。     

Concrete with a Crack Treated by Silane Soakage

If a crack appears in marine or concrete structures due to chloride corrosion, it will be a convenient channel for the chloride to penetrate into the concrete and easily corrode the steel bars and damage the concrete. A concrete specimen with a 0.2mm wide crack was prepared. After the specimen was soaked in a silane solution, emulsion and gel, a chloride ion corrosion test was carried out. The analysis of two dimensional chloride content shows that the silane soakage treatment of cracked concrete seals the crack and prevents further corrosion.     

DCPTA与CCC复配对寒地春玉米茎秆抗倒伏特性及光合作用的影响

为了研究新型植物生长复配剂对寒地春玉米抗倒伏特性及光合作用的影响,试验选择3种化控剂进行试验,其中2种为已用于大田生产的化控剂,分别为玉黄金(YHJ)和吨田宝(DTB),第三种为实验室自行配置的以DCPTA（2-(3,4-二氯苯氧基)-乙基-二乙胺）和CCC（氯化氯代胆碱）为主要成分的复配剂(FPJ)。结果表明,复配剂(FPJ)和玉黄金(YHJ)处理后玉米株高及穗位高降低,基部节间长度降低,基部节间直径增加。吨田宝(DTB)处理则增加了株高、穗位高和节间长度。以抽雄后10天为例,经过复配剂(FPJ)处理后的1、3、5节间长度分别比对照降低12.62%、9.49%、6.51%,而节间直径比对照增加了13.70%、12.37%、12.69%。复配剂处理能增加玉米茎叶干物质积累,部分处理差异显著。经复配剂处理后的叶面积指数与对照差异不显著。经复配剂处理后叶绿素荧光参数Fo（初始荧光）及qN（非光化学淬灭系数）数值下降,Fv/Fm（可变荧光/最大荧光）及qP（光化学淬灭系数）数值增加,这说明复配剂喷施处理不但对降低株高,增加抗倒伏性状有作用,也促进了玉米叶片光合作用,为玉米最终获得高产奠定基础。     

再生混凝土抗碳化性能试验研究及理论分析

通过快速碳化试验,以再生骨料掺量、水灰比、水泥用量、原始混凝土强度和矿物掺合料为影响因素,对再生混凝土的碳化性能进行研究。试验结果表明：再生混凝土的碳化深度随水灰比、再生骨料掺量的增加而减小,随原始混凝土强度的增大和水泥用量的增加而增大,适量添加矿物掺和料能降低再生混凝土的碳化深度,提升其抗碳化性能。在已有的普通混凝土碳化模型研究基础上,结合本试验和中国其他学者的试验数据,建立了再生混凝土碳化深度预测模型,模型预测结果与试验值吻合较好。