Applied Mechanics and Materials Vols. 174-177

Abstract: The compatibility and mechanical property of two kinds of synthetic fibers to geopolymer were studied. Polyvinyl alcohol (PVA) and polypropylene (PP) were used as reinforcing fiber materials. The result shows that flexural strength of geopolymer is obviously increased by mixed with reinforcing fiber. PVA is better than PP in reinforcing the flexural strength, both of these fibers have no significant effect in reinforcing the compressive strength to geopolymer.

Abstract: The cellulose nanofibers (CNFs) were made from the wood powder with the chemical and the mechanical treatment. The image of the scanning electron microscopy (SEM) could help to analysis the morphology of the obtained CNFs combined with the photographs of dispersions of the CNFs’ suspensions. It was found the fibers distribute uniformly, and the high aspect ratio was be calculated through the SEM images. Then the obtained CNFs were used as the fiber-reinforced material in the epoxy composite because of their structure of the network and the high aspect ratio. The mechanical properties of the epoxy nanocomposite were evaluated by tensile test, and the increase in Young’s modulus was observed at different fiber contents. The mechanism of action was analyzed combined the tensile test and the SEM images of fracture surface that the CNFs restricted the free movement of thermoset polymer chains by crack tip pinning. In the further study, more different content of the CNFs will be observed in the epoxy composites.

Abstract: The applications and effect of titanium dioxide are investigated in the aspects of coating,cement, concrete, wallpaper, glass, porcelain and PVC profile, from a perspective of environment-friendly building materials and according to the characteristics of structural materials and decorative materials. We should consider several problems caused by improper use of titanium dioxide among environment-friendly building materials and proposes that related standards that be established, titanium dioxide technology development,adjustment, control of different size and size distribution be focused on, and meet the needs of the client in the end

Abstract: Influence of addition amount and granularity of expandable graphite on the facing waterborne silicone-acrylic emulsion fire retardant coating was investigated. The results show that the waterborne silicone-acrylic emulsion fire retardant coating adding expandable graphite can improve its flame retardant time. The coating gets the best flame retardant effect when the addition amount of expandable graphite is 4%(by mass). The smaller granularity of expandable graphite can be more effective for improving the fire retardant performance.

Abstract: This paper deals with the viability of using lignin fibers as an additive in OGFC mixtures. Draindown test results indicated that OGFC mixtures with the two kinds of fibers can both be effectively used to retard draindown of the binder and mineral filler. Mixture designs were performed for a range of 3.5–6.0% asphalt content. Laboratory tests including indirect tensile load tests, Cantabro test, soaking Cantabro test were carried out on OGFC mixtures to determine the tensile strength, anti-abrasion ability and durability. The test results indicated that OGFC mixtures with lignin fibers showed improvement in strength, improved resistance to abrasion, and reduce moisture susceptibility when compared with mixtures without fibers. Comparison of test performance of two different lignin fibers added to OGFC mixture shows that flocculent lignin Fibers is superior to the Granular fiber.

Abstract: Fibres composite materials designed as glass fibre, carbon fibre and aramid fibre. They were used for chemical resistance, compressive strength, stiffness, impact resistance, and fire resistance. However, they had a number of limitations, including vandalism, accidental damage, short-term durability, high cost, and suitably qualified staff shortage. These problems could be solved by appropriate monitoring, suitably qualified designers and contractors. The design and use of fibre composite materials has become an important aspect of engineering.

Abstract: Based on the experimental study of the shear performance of three brand-new types of masonry brick wall and through the comparison of their shearing resistance by examining respective intrinsic factors, this essay aims to provide some reliable mechanical properties of these wall materials for their practical application in engineering and moreover offers some basic references for their popularization and application.

Abstract: A carbon black modified 0–3 cement-based piezoelectric composite was fabricated with piezoelectric ceramic [0.08Pb(Li1/4Nb3/4)O•0.47PbTiO3•0.45PbZrO3], sulphoaluminate cement and carbon black by compressing technique. The influences of poling conditions on the piezoelectric and dielectric properties of the composites were investigated. The results show that the higher poling electric field, the longer poling time and the higher poling temperature, the composites have the higher piezoelectric strain factor d33, piezoelectric voltage factor g33, dielectric constant εr and dielectric loss tanδ. At the same time, the carbon black modified composites are polarized more easily than the unmodified composites, and have better piezoelectric and dielectric properties. Meanwhile, the optimum poling conditions were obtained, and the optimum poling field E, poling time t and poling temperature T were 4 kV/mm, 20 min and 80 °C.

Abstract: This paper presents an experimental study to determine the thermal transmittance of various types of lightweight concrete with an objective to assess the applicability of lightweight concrete as a roof insulation material. The lightweight concrete ranging in density from 400 kg/m3 to 1700 kg/m3 was investigated. The results were also compared with normal weight concrete. It was found that the expanded clay aggregate concrete with density of 700 to 900 kg/m3 had adequate insulation property and enough strength to be applied without the use of surface tiles. Lightweight concrete with Perlite provided better insulation than expanded clay aggregate concrete. Because of its lower in strengths, Perlite concrete required the use of surface tiles to permit maintenance access to roof.

Abstract: The accumulation of fly ash leads to severe problems in ecological environments. Various ways to excite the activity of fly ash in Portland cement based cementitious materials have been carried out for many years. In the present study, effect of large volume of fly ash in phosphate cement was studied. Dead burned magnesia, two phosphates (monoammonium phosphate and monosodium phosphate), and fly ash were used. The fabricated cement mortar specimens with different fly ash dosages were cured for 28 days in the lab air. Compressive strength was determined in 1d, 3d, 7d and 28d respectively. It is showed the compressive strength reduced with increase of fly ash content and increased with the curing time. After cured 28 days, the compressive strength of cement mortar developed to14MPa, when 80% fly ash was used. The reaction product, Na2HPO4•17H2O was found by X-ray diffraction analysis in sodium phosphate based cement. No ammonia gas was emitted and large volume of fly ash can be used in cement prepared from sodium phosphate. It is a new environmentally friendly cement material.