Advanced Materials Research Vols. 785-786

Abstract: The paper carried out comparative studies on the workability, mechanical properties and chloride permeation resistance of wollastonite micro fiber mortar and alkali resistant glass fiber（ARGF） mortar. The results show that the mechanical properties and chloride permeation resistance of wollastonite micro fiber mortar improve significantly. The mechanical properties of wollastonite micro fiber mortar have greater advance in 90°C humidity. The SEM analysis results show that wollastonite micro fiber can form three-dimensional skeleton in the mortar, and combine closely with cement hydration products. This can make the structure of hardened paste denser and lead to excellent properties of mortar. Meanwhile, the compressive strength of wollastonite micro fiber mortar with wollastonite micro fiber content 30%(by mass) is close to ARGF mortar with ARGF content 1.5% (in volume), but the chloride permeation resistance of wollastonite micro fiber mortar is much better.

Abstract: Waste residues derived from the breaking process of rocks have been many times inadequately discarded on the environment generating an environmental passive. The residues could be used in the production of self-compacting concrete (CAA) providing more sustainable constructions. To study different CAA mixtures the following tests have been performed in the fresh state: Water Absorption, L - Box, V - Funnel and Slump Flow Test. For the evaluation of mechanical performance, the concrete Compression Strength Test, Flexural Strength Test and Tensile Strength by Diametric Compression Test have been performed in the hard state. Technical and environmental viability in the addition of this type of residue for the studied percentages have been verified.

Abstract: The foaming agent used in lightweight gypsum-based foam concrete was discussed. The effect of the single-doped foaming agent, codoped foaming agent and ternary foaming agent on the settling height, bleeding volume and defoaming time of fresh foam were investigated. The results show that ternary foaming agent has potential synergistic effects for reducing settling height and bleeding volume and retarding defoaming time of fresh foam. While applying this new compound foaming agent to the manufacture of the lightweight foam concrete blocks, samples with better-performance were obtained.

Abstract: Polyacrylate dispersants were synthesized by applying orthogonal array experiment method, among which the affecting factors include chain transfer agents: isopropanol (IPA). dodecyl mercaptan (DDM); initiators: benzoylperoxide (BPO), azobisisobutyronitrile (AIBN) and their contents, temperature, the content of acrylic acid and types of the monomers of solvation chains, of which poly (methacrylate), poly (ethyl acrylate), poly (butyl acrylate) were solvation chains. The optimal factors were obtained by comparing the viscosity decrease of the unsaturated polyester resin (UPR)/aluminum hydroxide (ATH) composites with different dispersants, and it showed that the dispersant with poly (butyl acrylate) as solvation chain whose length is around 7.0nm has the best result of improving rheological properties of UPR/ATH Composites and reducing systems thixotropy.

Abstract: The paper has learned on the preparation of nanometer carbon black and polypropylene nanocarbon black-polypropylene composite material by using the small extrusion blending mixer which has been designed by our team. The results show that: Resistance of nanometer carbon black - polypropylene composites decreases with increasing carbon black content and extrusion mixing times. Through single factor experiment and orthogonal experiment to determine the optimum process conditions are at 260°C, nanocarbon black content 60%, extrusion mixing times 5. Under these conditions the resistance of nanometer carbon black-get polypropylene composites is 12.73 ohms.

Abstract: The mechanical properties and thermal shock behavior of Mg-PSZ/LaPO₄ ceramics was investigated. The thermal shock resistance of the materials was evaluated by water quenching and a subsequent three-point bending test to determine the flexural strength degradation. Mg-PSZ/15LaPO₄ composite showed a higher thermal shock resistance and behaved as a typical refractory. The calculation of thermal shock resistance parameters for the composites and the monolith had indicated possible explanations for the differences in thermal shock behavior.

Abstract: Different flame retardant contents of polyurethane rigid foam (PRF) were prepared in this paper. Combustion performances of PRF were tested by cone calorimeter (CONE). Fire risk of PRF was evaluated based on Analytic Hierarchy Process (AHP). The evaluation results were compared with the traditional LOI results. It was found that the evaluation method based on AHP combined with CONE test results for evaluating fire hazard of thermal insulation material for exterior walls of buildings is more accurate and objective compared with the method of the traditional LOI.

Abstract: The characteristics of the woven fabric laminates structure is described. The steps and method of building the woven fabric laminates structure finite element model in MSC Patran is provided. The accuracy of this method is verified by a group of finite element calculation and experimental data.

Abstract: Curing conditions is one of the most influential factors on mechanical properties and durability of concrete. The mechanical properties (strength and dynamic modulus of elasticity) and durability (water permeability, air permeability and coulomb electric flux) of concrete under water curing and air curing were analyzed through the tests, and the significance of the curing conditions influence on mechanical properties and durability were compared. Test results indicate that the effect of curing conditions on the durability was much large than on the mechanical properties, and strength should not be the single control indicator while considering the effect of curing, moreover the some durability indicators of concrete also should be taken into consideration, which can provide the reference for engineering application.

Abstract: Water absorption behavior and mechanical properties variation of the carbon fiber reinforced epoxy matrix composites (CFRP) immersed into artificial seawater were investigated by experiments. The rate of water absorption of the composite specimens is gradually reducing as the duality of immersion increasing. Due to the reversible and irreversible changes in the resin matrix and the failure of the fiber/matrix interface, the tensile strength, the flexural strength, and the ILSS of the composite specimens after 70 days immersion decreased 9.3%, 13%, and 17% respectively. And the tensile modulus and the flexural modulus the specimens after desorption were 83% and 70% of the original state, respectively