Papers by Author: Wei Xin Hu

Abstract: Lightweight aggregate concrete with bleed air : the air-entraining agent added to the lightweight aggregate concrete , cement paste to form the porous structure of the porous structure of the right amount of artificial lightweight aggregate concrete . Reduce the density of the concrete to improve the insulation properties of the concrete . Applied to structural insulation concrete strength than 20Mpa, the thermal conductivity is less than 0.36W / ( m • K) . Of lightweight aggregate structure insulation concrete materials properties and microstructure of variation with air entraining agent .

Abstract: This paper addresses the efficiency of using recycled concrete as an aggregate by systematically presenting results on the influence of fly ash on recycled aggregate concrete (RAC) properties. The percentage of recycled aggregate replacements of natural aggregate used by weight was 50%. Fly ash (FA) was used as 0, 10, 20, 30, and 40% by weight replacement of cement. The results showed that an increase in the W/B decreased the resistance to carbonation depth. Nevertheless, the use of FA as a substitute for cement decreased the carbonation depth of the recycled aggregate concrete. Being analyzed on the basis of Gray Theory, it can be seen that the biggest influence on the depth of carbonation of the recycled aggregate concrete comes from W/B, then the carbonation age and FA content affects the least.

Abstract: A new environment-friendly wall material- the unfired brick is produced by using clay, carbide slag, fly ash and cement as the main raw materials，and certain amount of chemical excitator. The primary mixing ratio is designed on the basis of its mechanical properties and durability. When adopting water curing under normal temperature and atmosphere pressure，the compressive strength，flexural strength and frost resistance of the unfired brick are measured. The results reveal that the optimum mixing ratio for unfired brick is: Carbide slag 30%，fly ash 30%，cement 25% and clay 15%. For the unfired brick formed by vibration with the optimum mixing ratio，the min. compressive strength of each brick is more than 10 MPa, the overall properties meet the requirement as specified in standard JC 239—2001“Fly Ash Brick”.

Abstract: Based on the investigation and detection of Dongji Bridge, a reinforced concrete (RC) T-beam bridge, the major diseases of the bridge was identified. The disease characteristics and rules are classified, the strength of the bridge was analyzed by finite element technology. Research is expected to provide scientific and rational basis for maintenance and reinforcement of Dongji bridge and same style bridges, and lay a foundation for further research work for RC T-beam bridges.

Abstract: This study was carried out to test the feasibility of a mixture of cement, waste concrete powder (WCP) for their permeability, compressive strength and flexural strength. Various samples with different mass ratios of this mixture were tested to determine their permeability, compressive strength and flexural strength. The best proportions of 10% WCP, 90% cement and 0% NaOH excitant with a value of 51.3MPa was obtained at 28d, and the flexural strength can reach 8.6MPa. Moreover, the samples containing 10% WCP , 90% cement and 1% Na₂SiO₃ excitant also showed quite good compressive strength and flexural strength with values of 45.1MPa and 8.3MPa, respectively, while the samples containing 30% WCP and 70% cement showed low compressive strength and flexural strength.