Applied Mechanics and Materials Vols. 584-586

Abstract: The article reports a laboratory experimental programme that investigated effect of metakaolin on the early strength of concrete made with ternary combinations of Portland cement (CEM I) with ground granulated blast slag (GGBS) and metakaolin (MK). The various level of cement combinations (65%CEM I+30%GGBS+5%MK, 45%CEM I+45%GGBS+10%MK and 45%CEM I+40%GGBS+15%MK) was examined in comparison to CEM I and equivalent GGBS binary concretes for up to 28 days. Results show that the reduction in early strength is greater with the higher cement replacement level. However, the ternary concrete containing 15%MK has minor increase in early strength compared to those with 10%MK but a significant increase in strength is examined at later age (28 days). It is concluded that the presence of MK compensates the adverse effect of GGBS at early strength development and improves the strength at later ages.

Abstract: Bond-slip properties of concrete reinforced by bamboo-based fiber composites were investigated. The influences of strength grade of concrete, bond length, strength grade of bamboo-bar and section form were studied based on the L₁₆(4⁵) orthogonal experiment. The function law was uncovered to support the anchoring checking between concrete and bamboo-based fiber composites. The results show that: the tensile strength of bamboo-based fiber composites stables at 200Mpa with large inflation rate; section form of the composites is the key influencing factor, but should not be too large; bond length and strength grade of concrete are important factors; tensile strength of the composites is not significant factor. C35 concrete, 50 mm bond length, 200Mpa tensile strength of the composites and 10mm*10mm section form are the optimal combinations.

Abstract: In order to investigate the effect of Nano-SiO₂ on the compressive strength of concrete, the paper studies the effect of different mixing ratios (0%~3%) on the compressive strength, and the effect of age on the compressive strength of nano-concrete. Research shows that the incorporation of Nano-SiO₂ increased the compressive strength of concrete: it increases slowly with the mixing ratio 0%~1%; the growth rate is declining when the mixing ratio is 1.5%~3%; the optimal mixing ratio is 1.0~1.5%, which can replace 3.33~10% of cement.

Abstract: Green high performance concrete is concrete materials which can reduce the load of the earth's environment, coordinate development with the ecosystem and create comfortable living environment. The relationship between the construction materials and the sustainable development and the characteristic of green high performance concrete were introduced, the measures of green concrete production was analyzed and the work essential for the development of green high performance concrete was proposed in this paper. The research shows that the development of green high performance concrete is the inevitable way for the sustainable development of concrete.

Abstract: The volume deformation test, differential scanning calorimetry and chemical titration technique were used to experimentally research the interventions of retarders on the free autogenous volume deformation of cement paste doped with CaO expansion clinker at different ages systematically, as well as the hydration rate and hydration process of CaO expansion clinker. Two types of retarders were used as following: sodium gluconate and sodium citrate. The experimental results show that the two retarders can delay the hydration process of CaO expansion clinker, slow down its hydration rate both in pure water and cement paste. At the same time, the free autogenous volume deformation of cement paste was increased. In this sense, the use of retarders is favorable to improve the expansion efficiency of CaO expansion clinker.

Abstract: With the study of permeability of plain concrete and concrete mixing with fly-ash and concrete mixing with fly-ash and nanoSiO₂ as admixture for resistance to chloride ion, the outcome of the test goes that the permeability of concrete with nanoSiO₂ for resistance to chloride ion will be increased considerably.

Abstract: 4 kinds of mix proportion High performance concrete (HPC) was manufactured, whose material was produced from Inner Mongolia areas. During the brine corroded HPC experiment, the effects on surface chloride ion concentration of HPC, which was produced by different curing age and soak time, were studied. And the resistance to corrosion of HPC was analyzed. The curing period of HPC was adopted as 28d, 56d, and 90d. The soak period of brine-corroded HPC was 1 year. The changes of HPC surface chloride ion concentration were obtained in the experiment. Results show that, in the brine-corroded environment, the surface chloride ion concentration of HPC decreases obviously by the extension of HPC curing period. Furthermore, the surface chloride ion concentration of 4 HPC samples increases by the extension of HPC soak period, whose late growth is becoming gently. In the meanwhile, the regression relationship between HPC surface chloride ion concentration and different curing period, soak period is achieved.

Abstract: This paper, with the help of FEMLAB Software, analyzed the change of thermal resistance value of the same hollow block with different number of air layers or with the same rate of holes but different length of air layers and came to such a conclusion that the thermal resistance value can be promptly raised by increasing the number of air layers of the hollow block but decreased when an air layer is equally divided into several holes.

Abstract: New urbanization is an important feature of China's development. The development of urbanization has a far-reaching effect on the building materials industries. The development of the building materials industries is closely interrelated with all of the national economy, and it is obviously affected by macro economy and investment in the fixed assets. In the national economy, building materials industries is an important basic one, and plays an important role in the course of the industrialization and urbanization of our country. Urbanization needs to speed up the upgrade of the building materials industries transition, and come true the new Chinese-style industry. In the building materials industries, there are still many problems, such as Low-level competition, high pressure in eliminating the backward, and so on. The building materials industries provide an important material foundation to fixed assets investment of the urbanization.

Abstract: Combined with the heat-resistant concrete used for the construction of a company’s roaster, on the basis of preliminary preferred components for the concrete, with the design theory of ordinary concrete mix ratio, the design study of the mix ratio for C20 ~ C35 heat-resistant concrete was carried out. The study results showed that, the strength of the heat-resistant concrete formulated by the design theory of ordinary concrete mix ratio could meet the requirements, but the strength and water-cement ratio could not satisfy the linear equation. The study provided theoretical reference for the design of mix ratio for heat-resistant concrete.