Applied Mechanics and Materials Vols. 174-177

Abstract: The autoclaved aerated concrete is a new type of wall material of energy reserve and enviroment protection, it has good economy profit and social profit during basic construction. Basic on application of aerated concrete in Hunan, this paper discussed its application from material, construction, plastering and existing problem. It is reference for relevant design and construction people.

Abstract: To discover the fatigue behavior and durability of the new type fiber concrete named “steel fiber reinforced polymer high strength concrete (SFPHC)”, considering climatic conditions in Guangdong Province, using research method of theoretical analysis combined with experimental study, thermal fatigue behavior of SFPHC used in bridge superstructure in three different temperatures (20°C，50°C，80°C) is discussed and compared with concrete C60 which has similar static mechanical properties at room temperature. The results show that the thermal fatigue performance of SFPHC can be described effectively with the proposed computing formula, and the fatigue performance has been greatly enhanced compared with the C60 concrete.

Abstract: Keywords: High Performance Concrete, mix proportions, compressive strength , and durability Abstract. The use of concrete materials to date, remain a key ingredient in such construction work on the construction of building, bridges and infrastructure. One indicator is the increased production of readymix concrete which is nearly 16 billion tons in 2010. But the increased used of concrete, apparently bring the impact of environmental damage. This is due to the fact that production of raw materials contributes greatly to CO2 in the air. One effort to reduce such impact is to use of high performance concretes. Mix proportion of High Performance Concrete are strongly determined by the quality and availablity of local materials. The implications of research result from other countries can‘t be directly used. Therefore is need to the research on development of High Performance Concrete mix using locally available materials. In this research the mix proportions for f’c : 60 and 80 MPa are developed using local materials that are commonly used by readymix producers. The high Performance Concrete is developed based on compressive strength and durability. The result is expected to be applied to readymix industry particularly for construction use in Indonesia.

Abstract: Alkali activated slag cement was a new green cementing material with many performances. Whereas, high viscosity and bad workability of the fresh mixture were the matters to embarrass its application. For exploring the special superplasticizer, the adsorption characteristics of surfactant on slag was studied, by UV Vis Absorption Spectrum Method. The results showed, first, the adsorbed amount of cationic surfactant [CH3(CH2)11N(CH3)3]Cl was the highest value among the five surfactants, 12.8 mg/g. Second, the effect of alkali on the adsorbed amount of surfactant was complex. Cationic surfactant had cooperativity with alkali. But, adding water glass, the adsorbed amounts of the surfactants on slag were negative, because it was both colloid property and alkali solution property. Finally, the retarder of YP-3 made the adsorbed amount of ionic surfactant to increase, due to YP-3 contracted electric double layer in the surface of slag.

Abstract: The artificial lightweight aggregates (ALAs) were manufactured using dredged soil produced at thermal power plant and waste catalyst slag by direct sintering method at 1050~1250°C for 10min. The ALAs of 100% dredged soil showed the black core phenomenon even at the low sintering temperature as 1050°C and become lightened by bloating pores in black core area with sintering temperature. On the other hand, the aggregates with 100% waste catalyst slag did not showed black coring and bloating phenomenon and had the low forming ability and many cracks inside. Adding the dredged soil to the waste catalyst slag decrease the specific gravity by promoting the black coring and bloating inside. The water absorption(%) of ALAs decreased with sintering temperature. The ALAs fabricated in this study showed the specific gravity of 0.8~2.0 and water absorption of 2~16% so it could be applied to various fields such as the lightweight concrete or the field of the porous carriers for purification of a contaminated soil or water.

Abstract: With the rapid development of science and technology of concrete, the direction of research is changing from single high strength to high performance (strength and durability).Admixtures can improve concrete workability and improve resistance corrosion, especially it can inhibit alkali-aggregate reaction. Admixtures are paid attention to researchers in this field. In order to realize research and application of high performance concrete for the better, this paper systematically expounds the mineral admixtures and biomass admixtures. Mineral admixtures cost is higher, and it is limited available resources. Biomass admixtures have recycling, sustainable application and other characteristics, so it has the very good application prospects.

Abstract: The explosive spalling of high-strength concrete due to fire is a problem that has garnered increasingly widespread attention, particularly the explosive spalling of reactive powder concrete (RPC). For years, based on the vapor pressure mechanism, the addition of fibers has been demonstrated to be somewhat effective in protecting against spalling. However, relevant experiments indicate that fibers are not effective for dense concrete, which is a challenge for the simple vapor pressure mechanism in providing spalling resistance for RPC. The authors found that silica fume plays an important role in the explosive spalling of RPC. Thus, four classes of RPCs with different ratios of silica fume were prepared, and the spalling phenomena and the inner temperature distribution during heating were investigated. The results show that silica fume content has a prominent effect on the spalling process of RPC.

Abstract: Ferrochrome slag, an essential component in stainless steel, is the by-product of ferrochromium production. The composition of the ferrochrome slag and leaching tests show that the chromium content, 3.68%, is high, although the data of leaching tests under normal conditions is very low. Leaching test was performed on an oscillating shaking table with ratio adjusted to 150r/min at L/S 8 and 80°C, during 5h. The maximum content of water-soluble Cr (Ⅵ) is 2.78μg/g (0.3475 mg/L) from ferrochromium slag under these conditions. The soluble (Cr6+ and Cr3+) content rise in the solidification process，with the increase of ferrochrome slag. The Water-soluble Cr (Cr6+ and Cr3+) under different cured times can’t be detected. The content of ferrochrome slag reached 10% is the best ratio by comprehensive consideration of water-soluble Cr (Ⅵ) of all processes, compressive strength and relevant national standards.

Abstract: Experiment with intensity level for the LC30 ceramsite concrete as the research object, changing the content of cement, GRT fiber, rubber powder by the orthogonal test to configure GRT fiber—rubberized haydite concrete samples, maintenance samples 7d and 28d in standard conditions and respectively testing their bend strength. Through the analysis of the test data, using multiple regression analysis established the GRT fiber—rubberized haydite concrete 7d and 28d bend strength regression formulas.By means of BP neural network theory combine MATLAB programme established GRT fiber—rubberized haydite concrete 7d and 28d bend strength neural network model.Finally using 3 groups new test data to compare the value of multiple regression equations and BP neural network’s predicted value.The results indicate that the multiple regression equations of 28d’s and 28d’s BP neural network model are availabled.But because of the water and cement which in the GRT fiber—rubberized haydite concrete can not hydration reaction sufficiently during the 7d’s,so the multiple regression equations of 7d’s is unavailabled.

Abstract: The colour change and flextural properties of recycled milk-cartons/PE composite siding after tested in UV light accelerated aging champer and xenon lamp accelerated aging champer were studied. It showed that:(1)The ΔE value of samples in UV light champer was higher a little than it in xenon lamp champer after tested in later 1000h, which indicated UV light accelerated aging had more serious damage on material compared with xenon lamp accelerated aging; (2)The MOE of samples reduced 26.24%、39.82%、45.44% respectively after tested in UV light champer for 500h, 1000h, 1500h, with the MOR reducing 18.39%、19.01%、30.65%; while the MOE reduced 11.91%、29.60%、44.94% respectively after tested in xenon lamp champer for 500h, 1000h, 1500h, with the MOR reducing 8.53%、8.21%、26.02%, which showed that the effect on flextrual properties of UV light champer was greater than xenon lamp champer; (3) FTIR analysis showed it appeared carbonyl absorption peak on sample’s surface and methylene content increased a lot, which indicated polymer molecular chains had degraded into samll molecular chains.