Advanced Materials Research Vols. 168-170

Abstract: A new cast-in-situ slab which is filled with novel filled material (EPS-block) consisting of disused expanded polystyrene plastic granule, cement and building cementing powder is invented. EPS-block with perfect centrosymmetric torus shape is very suitable for filling into two-way slabs. It breaks a new path to use disused expanded polystyrene foam, and reduces environment pollution greatly. Through the practical study of the slab with EPS-block, the appropriate construction method is found out, and the dependable construction technique is afforded for further development of the slab with EPS-block.

Abstract: Based on orthogonal array testing strategy (OATS), the effects of sand-binder ratio (S/B), water-binder ratio (W/B), and the ratio of steel fiber volume to reactive powder concrete (RPC) volume (STF/R) on the compressive strength and chloride diffusion coefficient of RPC were investigated using an artificial neural network method. Research results reveal that the compressive strength of RPC approaches summit when STF/R is 2% or W/B is 0.18-0.2%, and decreases with the increasing of S/B. Furthermore, the chloride diffusion coefficient increases with W/B or STF/R and decreases with S/B.

Abstract: Aim & Goff model was used to predict the packing degree of cementitious materials including cement and silica fume. The mix proportions of reactive powder concrete (RPC) with different packing degree and calcium-silicon ratio of cementitious materials were designed and a strength test was carried out. The study results reveal that the flexural strength and compressive strength of RPC are related to the packing degree and calcium-silicon ratio of cementitious materials. For the mix proportion of RPC with the calcium- silicon molar ratio of 1.353 that is slightly less than the theoretical value of 1.42, where calcium hydroxide can react with silicon dioxide more fully, its strength of RPC approaches summit although its packing degree of cementitious material is not the largest one.

Abstract: The mitigation of earth force by placing expanded polystyrene (EPS) geofoam buffer between retaining wall and backfill soil under dynamic loading is a topic worth consideration. In this paper, the effects of EPS geofoam buffer on the reduction of thrust wall force are numerically studied to simulate three reduced-scale models of rigid walls using a large shaking table. Numerical simulation technique using the finite element program Abaqus is described. The paper shows that the numerical Abaqus models are able to capture the trend in earth forces with increasing base acceleration for all three models. The use of the EPS geofoam as a compressible buffer yields obviously reduction of the lateral seismic thrust against retaining wall. The quantitative dynamic load–time response of the numerical simulations was in good agreement with measured physical test values.

Abstract: Tunnel lining concrete segment is the most critical and important structural member of shield tunneling. This investigation designed and produced high-performance composite concrete segment (HCCS). Some key indexes that affect the properties of segment were tested, such as impermeability, volume stability, mechanical property, etc. The results indicated that the impermeability of HCCS concrete cover was excellent and the chloride diffusion coefficient decreased one order of magnitude compared to that of the ordinary segment concrete cover, while the service-life of HCCS increased more than ten-fold. The volume stability of HCCS concrete cover and concrete structure layer were good and the better compatibility in the volume deformation of the whole structure was shown. Furthermore, the mechanical properties of concrete cover and concrete structure layer met the project requirement perfectly, ensuring the higher durability and longer service-life of HCCS effectively.

Abstract: The mechanics behaviors on three-point bending of brazed aluminum honeycomb panel by FEM are investigated in this paper. The results show that honeycomb panel have three typical failure modes under bending load：failure of honeycomb core collapse, the whole panel bending failure and face sheet shear failure. Honeycomb lateral bending failure load is greater than the longitudinal bending failure load. When the ratio of honeycomb core thickness and panel thickness is between 10% to 15%, the strongest cellular panel bending occurs.

Abstract: This work try to deal with the analysis of a class of sandwich panels widely employed in engineering constructions. In order to study its structure behavior, a systematic experimental study on both roof and wall sandwich panels filled with Polyurethane foam (PU) under uniformly distributed load is conducted. Informed by the tests, appropriate finite element models are developed to model the tests.

Abstract: Recycled waste polystyrene foam can be used as heat-resistant construction material, which helps reduce white pollution, benefits the renewability of resources, and brings a good economic and environmental return. In this paper, non-autoclave aerated concrete is made, which uses foam of polystyrene as its packing material，it also gives a research on performance of polystyrene-aerated concrete materia composition.

Abstract: Based on experiment, the mix proportion matching with the design and construction requirements is obtained. It meets with the requirement of pump structure on the basis of meeting the strength requirement. On this basis, the basic physical and mechanical performance is studied and the conclusion is that steel fiber high-strength concrete has excellent resistance to splitting, bending and drying shrinkage. The splitting strength and bending strength of steel fiber high-strength concrete named CF60-2 is respectively 38.7% and 56.8% higher than that of plane concrete named C60. The drying shrinkage rate of CF60-2 is 45.5% lower than that of C60 in three days. The results have an important guiding significance to steel fiber high-strength concrete in theoretical and engineering practice.

Abstract: Extreme water repellency is greatly desired for anticontamination and self-cleaning applications in new building walling materials. A superhydrophobic carbon film was fabricated on the pure nickel substrates by a novel vapor phase transport method. The surface of morphologies of the pure nickel surface was characterized using a non-contact mode of atomic force microscope (AFM) and the structural properties of as-grown carbon film was characterized using scanning electron micrograph (SEM). The contact angles and the rolling angles on such films were measured through an optical contact angle meter. Wettability studies revealed the films exhibited a superhydrophobic behaviour with a higher contact angle of 160.7°±2.1° and lower rolling angle of less than 4°-a water droplet moved easily on the surface. SEM showed that compared with pure smooth nickel surface, a lotus-like structrure with micro-nano hierarchical papillae was obviously observed on the superhydrobic carbon film surface. Such a speccial surface microstructure may result in the superhydrophobicity.