Adhesion of Recycled Concrete Aggregates,Demolition Debris,and Asphalt

In this investigation, rolling bottle tests and boiling water tests were conducted to evaluate the effect of different fillers and treatments on the adhesion between recycled concrete aggregates (RCA) and asphalt. The test results when 100% RCA loose mixtures were evaluated indicated that the filler that achieves the best asphalt aggregate bond was grey Portland cement. Curing the mixture in an oven for 4 h at mix temperature before compacting and coating RCA with bitumen emulsion are treatments that achieved satisfactory adhesion results as well.     

PFG-NMR self-diffusion in casein dispersions: Effects of probe size and protein aggregate size

The self-diffusion coefficients of different molecular weight PEGs (Polyethylene glycol) and casein particles were measured, using a pulsed-gradient nuclear magnetic resonance technique (PFG-NMR), in native phosphocaseinate (NPC) and sodium caseinate (SC) dispersions where caseins are not structured into micelles. The dependence of the PEG self-diffusion coefficient on the PEG size, casein concentration, the size and the mobility of casein obstacle particles are reported. Wide differences in the PEG diffusion coefficients were found according to the casein particle structure. The greatest reduction in diffusion coefficients was found in sodium caseinate suspensions. Moreover, sodium caseinate aggregates were found to diffuse more slowly than casein micelles for casein concentrations >9 g/100 g H₂O. Experimental PEG and casein diffusion findings were analyzed using two appropriate diffusion models: the Rouse model and the Speedy model, respectively. According to the Speedy model, caseins behave as hard spheres below the close packing limit (10 g/100 g H₂O for SC (Farrer & Lips, 1999) and 15 g/100 g H₂O for NPC (Bouchoux et al., 2009)) and as soft particles above this limit. Our results provided a consistent picture of the effects of diffusant mass, the dynamics of the host material and of the importance of the casein structure in determining the diffusion behavior of probes in these systems.     

Interface shear strength properties of geogrid-reinforced steel slags using a large-scale direct shear testing apparatus

This research evaluates the shear strength properties of unreinforced and geogrid-reinforced ladle furnace slag (LFS), electric arc furnace slag (EAFS) and a blend comprising 50% LFS and 50% EAFS (LFS50+EAFS50) using the large direct shear testing apparatus (DST). The large DST results of unreinforced steel slags indicated that LFS had the lowest shear stress ratio at the peak shear strength among all samples, while LFS50+EAFS50 samples (both unreinforced and reinforced) demonstrated the highest shear stress ratio amongst the tested samples. A higher apparent cohesion value was achieved with the inclusion of biaxial geogrid in LFS and EAFS samples as compared to the triaxial geogrid interface. The observed behavior can be attributed to the larger aperture size of the biaxial geogrid compared to the triaxial geogrid leaving more void planar space for a direct interaction between slag particles. In contrast, the apparent cohesion of LFS50+EAFS50 without a geogrid interface was high and did not change significantly with the insertion of geogrid. Given, the range of internal friction angles for ordinary soils, studied slag by-products achieved internal friction angles in excess of 59° (with no geogrid interface) and these significant values proved highly beneficial application for these waste materials in pavement construction.     

革命文物数字化聚合体的构建与设计应用研究

目的 以文化基因之间相似性关系为基础,对革命文物进行关系匹配,构建革命文物数字化聚合体,整体性地展现革命文物关系并应用于设计创新当中,为革命文物数字化保护工作提出新的路径。方法 首先,对革命文物数字化聚合体进行定义,确定聚合体的基本构成单元U,U=(M,G,R):M=革命文物唯一标识/名称,G=革命文物文化基因,R=革命文物文化基因关系连线;其次,从本体属性中提取出满足创新设计应用的革命文化基因并进行类型维度的层次分级,建立以文化基因为基本遗传单位的革命文化基因数据库;最后,以革命文物为核心,以文化基因之间的等价性为关系连线,对革命文物数字化聚合体进行构建。结果 通过对革命文物数字化聚合体的构建,形成革命文物文化基因关系网络,有助于在革命文物的创新设计应用中提供设计因子与创意思路,提高再设计的潜力。     

Assessment of mechanical properties of concrete incorporating carbonated recycled concrete aggregates

An accelerated carbonation technique was employed to strengthen the quality of recycled concrete aggregates (RCAs) in this study. The properties of the carbonated RCAs and their influence on the mechanical properties of new concrete were then evaluated. Two types of RCAs, an old type of RCAs sourced from demolished old buildings and a new type of RCAs derived from a designed concrete mixture, were used. The chosen RCAs were firstly carbonated for 24 h in a carbonation chamber with a 100% CO₂ concentration at a pressure level of 0.1 Bar and 5.0 Bar, respectively. The experimental results showed that the properties of RCAs were improved after the carbonation treatment. This resulted in performance enhancement of the new concrete prepared with the carbonated RCAs, especially an obvious increase of the mechanical strengths for the concrete prepared with the 100% carbonated new RCAs. Moreover, the replacement percentage of natural aggregates by the carbonated RCAs can be increased to 60% with an insignificant reduction in the mechanical properties of the new concrete.     

Intensity enhancement of photoluminescent polyesters by photocrosslinking

A series of polyesters with alkylated triazole heterocyclic rings at the branches were designed and synthesized via the polycondensation reaction. The synthesized polyesters were examined with various spectroscopic methods such as Fourier transform IR, ¹H NMR and ¹³C NMR. The alkyl chain length at the branch was found to affect the thermal stability of the polyesters, which decreased with longer alkyl chain. These polyesters possessed an aggregation‐induced emission enhancement characteristic evidenced by the transformation of the clear solutions in tetrahydrofuran with weak greenish blue emission to cloudy solutions with enhanced blue emission when water was added to promote aggregation. Furthermore, enhancement in the photoluminescence intensity was observed when the polyesters underwent photocrosslinking upon UV irradiation and appeared as self‐assembled aggregates. The formation of aggregates in the water ? tetrahydrofuran solutions and after photocrosslinking was confirmed via TEM analysis. The SEM images showed that the photocrosslinked polyesters were highly porous which may enhance the π ? π stacking interaction that improved the photoluminescence intensity. © 2015 Society of Chemical Industry     

Examination of the Causes of Instability of Soy Protein Isolate During Storage Through Probing of the Heat‐Induced Aggregation

This study investigated the mechanism of instability of soy protein isolate (SPI) as influenced by thermal aggregation during SPI preparation. Samples with different degrees of aggregation but similar protein solubility were prepared by heating native SPI (5 % w/v) at 80 or 90 °C for different times before spray‐drying. The samples were then stored at 37 °C for up to 12 weeks and analyzed periodically by atomic force microscopy, gel permeation chromatography, and SDS–PAGE. All SPI samples underwent remarkable protein solubility decreases during the first 8 weeks of storage. The rates of solubility loss were positively correlated with the amounts and/or sizes of soluble aggregates contained in the initial samples (time zero), suggesting their nucleation and activation effects. Solubility tests in SDS–urea solutions and disulfide analysis indicated that non‐covalent interactions were the main driving forces for protein storage instability. Conversely, disulfide bonds and protein carbonyls were abundant in soluble aggregates, and their content increased markedly during storage. This effect suggested that covalent linkages acted as blockers for hydrophobic aggregation.     

Aerobic granular sludge in a sequencing batch reactor

In a laboratory scale sequencing batch reactor (SBR) granules were cultured under aerobic conditions. To enhance the growth of granular sludge the SBR was operated with very short sedimentation and draw phases resulting in the washout of slow settling biomass. Fast settling granules were retained in the reactor and thus had an advantage over flocs with a slower settling velocity. After 40 days of operation granules were the dominant form of microbial aggregates in the reactor, even though some pin-point flocs remained in the system. Granules taken from the reactor were stored for weeks without disintegrating. After about 130 days of operation the granule quality and COD-removal worsened. The reasons for that are yet to be investigated.     

Effect of sintering temperature on lightweight aggregates manufacturing from copper contaminated soil

Manufacturing lightweight aggregate (LWA) at high temperature is an effective way to immobilize heavy metals in solid waste. This work investigated the performance and solidification mechanism of LWA prepared from copper contaminated soil. The volume expansion of LWA could reach a maximum of 28%, and its lowest density accounted of 1.5 g/cm³, which met the standard requirements. Optical microscope and micro-CT test illustrated that the addition of Cu leaded to obvious phase separation in LWA. The Cu leaching result of LWA first increased and then dropped with the temperature. The XRD test found that the main formation phase of Cu in LWA were t-CuFe₂O₄ and amorphous phase that they had different acid resistance ability. XPS revealed that the main cause of the agglomeration of liquid phase in LWA was the chain broken reaction between Cu and Si–O tetrahedron. SEM-EDS results showed that the distribution of Cu and Si had a strong correlation, which meant that Cu mostly formed amorphous phase. This work showed the uniqueness of Cu in the high temperature immobilization and pointed out the best immobilization target phase.