Advanced Materials Research Vols. 163-167

Abstract: As the increasing environmental awareness, to explore no-chromium passivation technique on galvanized Zn coatings becomes one of the most urgent affair. In this paper, one kind of silicate passivation technics was invented and by which method silicate conversion film on galvanized Zn coatings with satisfactory property was got. It is found that solution composition and operating conditions of passivation affect the property of conversion film markedly, and the optimal technics is: Na₂SiO₃ 20 g/L, H₂SO₄ 5 mL/L, HNO₃ 5 mL/L, H₂O₂ 10 ml/L, pH 2.0, passivation time 20 s, temperature 25°C. The corrosion resistance of galvanized Zn coatings with different passivated method, including no passivated, Cr(VI) passivated, Cr(III) passivated and silicate passivated, were investigated by NSS test (5% Neutral Salt Spray). The silicate conversion film can keep no rust for 72 h and obviously shows the best property. All the results show that silicate passivation can provide galvanized Zn coatings superior anti-corrosion performance, so this new technics can replace the conventional chromate passivation technology to avoid the pollution of chromium and has a wider application in future.

Abstract: Based on ABAQUS finite element analysis, nonlinear analysis about mechanical performance of reinforced concrete beam-column joints under thermal-stress coupling is carried out. This paper mainly research the temperature field distribution, the beam deformation of frame joints under fire and the influence of different parameters such as the axial compression ratio, beam layer thickness, reinforcement ratio on fire resistance of frame joint. Conclusions was drawn as: forming temperature gradient from the outside to the inside in frame joint; displacement of the end of the beam suddenly increase after plastic hinge appearing, the sudden destruction contains contingency; Due to the damage began from plastic hinge at the end of the beam, the axial compression ratio has less influence about fire resistance of frame joint; The thicker of beam layer thickness, the longer of joint refractory limit; the higher of reinforcement ratio ,the later of plastic hinge 's formation, that is good for fire resistance.

Abstract: Estimation of construction and demolition (C&D) waste amount is crucial for implementing waste minimization program. Estimation of C&D waste amount generated is a mean in assessing the potential for waste reduction. Thus, a better understanding of C&D waste generation in terms of causes and sources can be achieved. The aim of this paper is to conduct a review on available construction waste quantification methods from previous studies, which have been utilized in certain countries, while attempting to choose the most suitable and applicable method, and to direct future studies for better quantification methods. This review is applicable only for building construction projects and did not include civil/infrastructure, demolition, renovation, and excavation projects. Six quantification methods and/or waste audit tool available from literatures are discussed, which include their limitation and future direction for this study. It is believed that some combination of these quantification methods could make a good impact in accurate numerical estimation of construction waste amount generated in building construction projects. A strong and accurate database as presented by Soliz-Guzman, combined with effective, vital, and resourceful estimation suggested by Jalali’s Global Index (GI), also with the aid of user-friendly software tool like the SMARTAudit could provide an effective and reliable waste quantification.

Abstract: The SMA 3D isolator is based on a new intelligent material: shape memory alloy, which compensate the weakness in stiffness of the laminated rubber bearing. Through the seismic analysis of the kettlewell double layer shell, the truss horizontal and vertical internal force dropped obviously with the SMA 3D base isolator, especially the outer part which easily happened deformed damage and the structure internal force distribution is more reasonable, the deformation in harmonies, the lattice damage of weakness part is limited and offer efficient protection. Either the acceleration analysis, the peak acceleration reduced significantly and time history tends to slow, the isolating effect of the SMA 3D base isolator is prior to the laminated rubber bearing.

Abstract: This article describes the physical and chemical properties of EMR and the preparation of a new building material with it. The results show that the main components of EMR are gypsum and quartz, supplemented by a small amount of cement, appropriate siliceous material and quicklime in EMR could be prepared high performance EMR autoclaved brick.

Abstract: In this paper, we take the polypropylene fibers in concrete mechanisms as the starting point, then analysis the impact of the following four effects on the properties of polypropylene fiber concrete: thickening effect, toughening effect, crack resistance effect, load transfer effect, from which was out the following useful conclusions: the rate of low-doped fiber reinforced concrete with polypropylene fiber content increases, can further reduce the spacing between fibers in concrete to enhance crack resistance effect, the intrinsic quality of concrete with high resistance to dynamic load characteristics of sensitivity is also can be improved, and after the concrete has better crack toughness, with due extension of time to eliminate vibration molding concrete thickening effect on the strength of the adverse effects; incorporation activity of mixed materials.

Abstract: The ballistic shotgun was employed to launch the deep penetration scaled earth penetrator in velocity of 510m/s 820m/s for investigating the ultra-high performance cementitious composite (UHPCC). The influence of the compressive strengths and volume fraction of steel fibres of UHPCC for the penetration resistance and front face damage were systematically investigated.

Abstract: Discontinuous yield of material as Jerky flow was explained. Then, the strain rate sensitivity (SRS) and instability criterion was given out. Some tests were carried out at constant stress rate, so Jerky flow is manifested as a discontinuity in the stress-strain curves in form of strain bursts. Finally, the dynamic behaviors of specimens during instability of thermal origin were simulated with COLSYS software, whose results are good with test ones.

Abstract: The explosion of fluid concrete under different explosive dosage is achieved by experiment as the main study means. After hardening, we carry out its compressive strength test by Shimadzu AG-X250kN electronic universal pressure machine. The experiment shows that compressive strength of hardening fluid concrete by explosion is higher than that in the same state. Explosive can increase compressive strength of concrete material.

Abstract: An improved shear-lag analytical model has been established to study stress transfer in carbon nanotube (CNT) reinforced polymer matrix composites with and without debonding interface. The Poisson’s effect and radial effect of matrix is considered in the model for the first time, and a simplified 2D representative volume element (RVE) is modeled using a four-phase composite composed of matrix, nanotube, bonded, and debonded interfaces in this analysis, and the axial stress for CNT and matrix and interfacial shear stress along the CNT is predicted. The results show that load transfer efficiency in CNT reinforced composites is affected by the debonding length, and the abrupt change of shear stress is existent at the tip of debonding interface.