Advanced Materials Research Vols. 374-377

Abstract: By means of two-scale method, the approximation solution of the displacement for structure of composites with small periodic perforated configuration is built, and the algorithm corresponding to two-scale finite element method is presented. One new method of higher order for computing approximate solution of the displacement in periodic perforated composites is given.

Abstract: In order to study the effect of fly ash (FA) and slag powder (SP) on coefficient of thermal expansion (CTE) of concrete, the influence of FA and SP to CTE of concrete was compared, the influence of replacement proportion of FA to CTE of concrete was tested, and the unhydrate mineral admixture particles were observed with SEM and validate with Energy Spectrometry. The results showed that the influence of FA and SP to CTE of concrete is different, the CTE of SP concrete is near to the norm concrete，but is higher than the FA concrete; With the replacement proportion of FA increased, the CTE of concrete decreased; The per strength CTE increased obviously when the replacement proportion exceed 10%, and the decrease of strength badly when the replacement proportion of FA exceed 30%; The unhydrate mineral admixture particles is one of the most important factors that influence the CTE of concrete, and the mineral admixture could influence the composite and the microstructure of cement paste, then cause the change of porosity and density.

Abstract: The modified tests are put on by selecting gypsum from different habitats, using doping technology and calcination technology. The tests results can be summarized as follows. Different kinds of gypsums have different effects on the strength of fly ash autoclaved products, and so do the gypsums collected from different habitats. Low-purity gypsums helps to improve the strength of autoclaved products. Low-purity scatter of gypsum can be achieved by means of natural doping and artificial doping, and natural doping is better. Calcined gypsum could increase the strength of fly ash products within a certain range, and the best calcining temperature is about 650°C.

Abstract: The bending mechanical properties of bamboo plywood which was glued with phenol formaldehyde (PF) resine were detected and analysised. The study results showed that the differences of the bending strength (MOR)and the elastic modulus(MOE) of bamboo plywood prepared separately within 110-130°C were not large, and MOR and MOE exceeded all the targets ruled by JB/T 156-2004. It was proved that the property of this kind of middle temperature PF resine was very well for using in bamboo plywood. When the load was the same, the differences of the deflection、the stress of the bamboo plywood prepared on the different hot-pressing temperature were very small too, but some differences existed in the those strains，and the strains on the lower sursurface of the boards were larger than those on upper surface. When the load was smaller, The deflection、stress and strain of the boards linearly changed with the load increase, which proved that the bamboo plywood mainly produced elastic deformation under this circumstances.

Abstract: Different contents of stearic acid were added to mixtures, and the influences of stearic acid as grinding aids on portland cement performances, including specific surface, compressive strength, hydration heat, Ca(OH)2 (CH) content, C-S-H gel and ettringite (AFT) content were discussed in this paper. The results show that the addition of small amount of stearic acid is enough, and excessive addition of stearic acid is not a good matter to cement grinding. Adding a small amount of stearic acid, not only don’t improve the compressive strength, but also lower the compressive strength significantly. Although the specific surface of samples with 0.1% stearic acid is lower than that of the samples with 0.025% stearic acid and reference, the compressive strength appears of higher than others. Addition of stearic acid affects not only on the rate of heat liberation, but also the hydration heat significantly. The addition of stearic acid has uncommonly impact on the content of CH, C-S-H and AFT in cement paste at 3 days, 7days and 28 days hydration age, the samples with 0.1% stearic acid has higher content of CH, C-S-H and AFT than others, and lower conversion content of AFT from 3days to 7days and 7days to 28 days. This can explain why the cement with 0.1% stearic acid is provided with the higher compressive strength than others, from the perspective of hydration production composition.

Abstract: The cement-base composite formwork reinforced by FRP is developed to act as permanent construction formwork. Considering such properties as the minor stiffness out of the plain and the smaller bending resistance of the formwork, the matched cross support device is designed which can be recycled. In this paper, components of the support device and the corresponding functions are introduced, the technological process is described. By means of finite element program, the appropriate support distances of formwork during concrete placement are calculated, the stress and deformation performances are also analyzed. In the end, economic benefit and environment efficiency of the permanent formwork system are discussed. The above research results indicate the feasibility and economy of the support system, which present a gist for investigation and application of the permanent FRP cement composite formwork.

Abstract: There is need to assess the potential of the construction materials for the green building future generation. Research is necessary for complete assessment of construction materials for present and future generation of green building. This paper provides a consistent basis and specific factors for construction materials based on eco-labeling sciences. Within the methodological framework, three categories of sustainable building materials’ implementation are discussed: economical implementation; environment implementation; and social implementation. The paper shows that green building improvements can be achieved with help of the choice materials based on existing factors of eco-labeling construction. Construction eco-labeling can help to select a suitable material for creating a better outdoor environment and indoor environment of building.

Abstract: Production process of sintered thermal insulation wall material with high content fly ash was investigated in this paper. The proper addition amount of fly ash, the types and addition amount of the binders, the demand of molding and the molding process as well as the schedule of sintering was determined. The results show that: When the addition amount of fly ash is 65wt.%, the plasticity index of mixture mad is still more than 8. The compressive strength of the sintered sample can reach 12MPa; the porosity is in the range of 40-50%; Bulk density is 1.45g/cm³. If the macro porosity of the industrial product is designed as 40%, the final bulk density can reach 1.40g/cm3, and the theoretical thermal conductivity is less than 0.88w/(m²•K). This product can me^{Superscript text}et the demand of building energy saving and replace traditional external wall thermal insulation materials.

Abstract: The depreciation of machinery and equipment of building construction, as an important factor, always plagues the development of their enterprises; How to extract depreciation effectively and reasonably for construction equipment is a problem faced by construction businesses. In this paper, the gray relational theory is used to analysis different depreciation programs by author, and then the author selects the best depreciation program from all programs. The time value of money, the service life span of machinery and equipment and other factors are considered in this paper. A theoretical basis is provided for the construction enterprise to extract depreciation fast and reasonably through analysis these factors. And then the feasibility of the method is verified through the example analysis.

Abstract: A new 3D unit cell model is developed for homogenization calculation of composites containing randomly dispersed ellipsoid inclusions. The new unit cell is constructed using the Ansys Parameter Design Language (APDL), taking the inclusion volume fraction, inclusion orientation and spatial dispersion as variables. A series of unit cells containing multiple ellipsoids, showing random distributions in particle size and position, were constructed and used for finite element calculation at microscale, the effective modulus of the composites with periodic microstructures, which modeled by the unite cells, were then estimated by homogenization. The influences of particle volume fraction and the particle stiffness on the effective elastic modulus of the composites were examined. The estimated results were compared with different particle volume fractions were calculated, and the calculated data was compared with other classic models.