Advanced Materials Research Vols. 919-921

Abstract: Abstract: 7 square steel tubular columns were tested to discuss the ultimate axial bearing capacity, ductility performance and the steel consumption under stiffened by steel belts and binding bars of different cross-sections. Test results indicate that only by increasing fewer amounts of steel usage, stiffened square CFST columns with binding bars can not only improve the overall effects of restraint and alleviate regional local buckling between the binding bars, but also improve the bearing capacity of concrete filled square steel tubular columns. The utility benefits and the economical benefit is considerable, deserving extensive use.

Abstract: Pumice concrete and volcanic concrete used in low-rise rural residential building more and more. In order to better realize the pumice concrete wall and cinder concrete wall compressive strength, respectively to make three slices of pumice concrete wall and three slices of cinder concrete wall, wall compressive experiment was carried out. The experimental results showed that the compressive strength of pumice concrete wall and volcanic concrete wall meet the requirements of the bearing capacity of masonry structure.

Abstract: Four I-section specimens have been produced, and epoxy resin structural adhesive and bolts have been used to combine the cold-formed thin-walled C steel with bamboo-wood composite plate, through which the cooperative work performance of the combined column was detected, and the failure mode and mechanism were explored. The feature of load vs. deflection and load vs. strain was also analyzed. Then stiffness and calculation formula of bearing capacity were proposed. The results show that the unitary mechanical behavior and plastic properties are very good, and the combined column is divided into three stages from loading to failure, including adhesive cracking, local area degumming and failure. And the stiffness accords with double slash model in serviceability

Abstract: To study the seismic behavior of Double-Wall Precast Concrete (DWPC) shear wall, three full scale specimens are tested and compared under low-cyclic reversed loading, including two DWPC shear walls and one normal Cast-In-Situ (CIS) shear wall. By observing their experimental phenomena and failure modes, contrasting their displacement ductility coefficients, hysteretic curves, skeleton curves and energy dissipation capacity, the seismic behavior were synthetically evaluated on aspects of strength, stiffness, ductility and energy dissipation. Compared with CIS specimen, DWPC specimens have higher initial stiffness, increased cracking loads by 43% to 47%, and the ultimate loads increased by 22% to 23%. The displacement ductility ratios also meet the ductility requirements with value of 5. The hysteretic curves of three specimens are plump, and the trend of skeleton curves is basically the same. The DWPC specimens demonstrated a good energy dissipation capacity. All the specimens had shown favorable seismic performance.

Abstract: Very large quantities of construction and demolition wastes and especially concrete wastes are produced yearly. Up to now, only a small fraction of these concrete wastes is re-used as recycled concrete aggregates (RCA) for the manufacture of concrete. In order to make good use of RCA in the concrete, it is very important to study the influence factor of the properties of RCA. In this paper, the influence of laboratory accelerated carbonation on the properties of recycled concrete aggregates has been studied. The results show that after the laboratory accelerated carbonation, the harden cement paste content of RCA measured by salicylic acid dissolution decreases, the density and specific surface area of RCA increase, and the porosity of RCA decreases, which leads to the reduction of water absorption of RCA.

Abstract: Transport performance of near-surface concrete is a main factor affecting the durability of concrete structures. Meso-structure of near-surface concrete and its effect on permeability were investigated. The near-surface concrete was divided into several layers, and by considering the dilution effect, the tortuous effect, and the interfacial transition zone effect on permeability caused by aggregates, together with hardened paste permeability, a computational frame for permeability determination of near-surface concrete was established.

Abstract: The high strength and high performance concrete C80~C100 is popularly used nowadays, especially in the West-Tower Project of Gungzhou. In order to provide reference for the use of high strength concrete and the development of ultrahigh pumping technology, the following six aspects were studied, namely the preparation of high strength concrete, the variation of the concrete mixture under high pressure, the index of the ultrahigh pumping concrete, the change after the pumping, the loss of the pumping pressure and the measurement of the pumping viscous resistance.

Abstract: Nanotechnology has experienced rapid growth, it can be seen the emergence of products and high interest researchers associated with nanotechnology. The implication process natural resources management is no longer limited to generating value addition, but were able to perform value creation. One potential source is the natural silica sand. Silica sand reserves in Indonesia, among others are, South Kalimantan, West Java, East Java and Papua. Utilization of silica sand has been used as a filler only on the construction materials at a price of 20 - 50 IDR/kg, while microsilica: 12,000 – 15,000 IDR/kg and nanosilica: 100,000-150,000 IDR/kg. This study develops the potential of silica sand in Indonesia through testing, XRF, XRD, SEM and PSA. Then further process by nanosilica’s equipment in Indonesia, resulting microsilica and nanosilica Indonesia. The end result made ​​comparisons with microsilica and commercial nanosilica. The results showed that the Planetary Ball Mill (PBM), High Energy Milling (HEM) can be used to generate microsilica. Polishing Liquid Milling Technology (PLMT) can be used to make nanosilica of Indonesia's natural resources, which is equivalent to nanosilica have traded commercial.

Abstract: Controlled Permeable Formwork Lining (CPFL) has particular water-storaging capacity, the mixing water remained in the CPFL can provide moisture curing for the surface layer concrete for a period time. In this paper, the water storage was tested, the appearance quality, rebound hardness and durability of the surface concrete were studied. Results shown that CPFL can significantly improved the appearance quality, early age rebound hardness, carbonation resistance, chloride ion penetration resistance and freezing-thawing resistance of the surface concrete; the coating age of anti-corrosion coating was shortened to 18 days, the cofferdam turnover rate was speeded up, the engineering cost was reduced; the coating adhesion was significantly improved and the thickness of dry coating film and adhesion of discrete were reduced. The benefit of using CPFL technology is remarkable, and it is worth promoting.

Abstract: The influence of construction seasons and curing condition on chloride ion permeability of entity structure concrete was analyzed, which was based on the monitoring of pier concrete quality constructed seasonal of Qingdao bay bridge. At the same time, durability of entity concrete structure was analyzed combining site construction technology.