Advanced Materials Research Vols. 1065-1069

Abstract: In this paper, iron-tailings was substituted for natural sand in self-compacting concrete(SCC). Iron-tailings SCC mix proportioning design at different substitution rates were made. Slump,slump-flow, the time T500(S) of the slump-flow reaching 500mm, J-ring test, U-flow test were used to evaluate the iron-tailings SCC mixture working performances at different substitution rates, which contrast to the common SCC working performances. Through the experimental results and their variation regulations, taking the single working performance into consideration,a reasonable range about the substitution rate of iron-tailings is obtained.

Abstract: In this paper, based on the analysis of cross-section of steam oxidation of Super304H sample at 600°C, thermal stress contours were obtained by using finite element analysis through establishing geometric model and refine meshing. After extracting the stress in the interface of oxide layer and analyzing the thermal stress, it can be found that there exists compressive and tensile stress in the interface between substrate and scale, which is affected by the slope of the interface.

Abstract: Considering the essential influencing factors for the mechanical properties of the engineered cementitious composite (ECC), the polyvinyl alcohol (PVA) fiber was used and a batch of cube specimens and thin plate specimens of PVA-ECC were manufactured based on the variation of water cement ratio, amount of fly ash and amount of water reducer. The compressive strength test for the PVA-ECC cube specimens and the flexural strength test for the PVA-ECC thin plate specimens were conducted. A practical decision-making frame based on the Analytic Hierarchy Process (AHP) method was proposed to solve the problem of the optimal mix proportion of PVA-ECC, which can take into account the compressive strength, the flexural strength and the corresponding deformation capacity together.

Abstract: Aiming at the problem of the Alpine, high altitude and other complex environment in the northwest area, and lack of concrete mix and durability data in this harsh environment. Based on the real engineering project, the effect of W/C and the content of cementitious materials on concrete performances were studied, the strength, impermeability and frost resistance of concrete which was mixed respectively two kinds of water reducer and maintained in standard condition and outdoor condition were Studied comparatively. The pore structure of cement paste which was added respectively two kinds of water reducer were also analyzed. The results show that: The self-made polycarboxylate superplasticizer has the effect of low temperature and early strength, and it also can ameliorate the internal pore structure of the sample and improve the impermeability and frost resistance, and improve the durability of concrete.

Abstract: supersulphated phosphogysum-slag cement (SSC) is a newly developed non-burned cementitious material. It’s mixed and ground with 40%-50% phosphogypsum, 40%-50% ground granulated blast-furnace slag (GGBFS), 2% steel slag and 4% portland cement clinker. But the component of SSC differs greatly from that of Portland cement, there is few application researches about the SSC. In order to realize resourceful utilization of phosphogypsum, the mix proportion design method of SSC are studied. The mix proportion design method for C30 are systematically studied and a design optimization was carried out. According to the design regulations of mix proportion of ordinary concrete and the characteristics of SSC, the C30 high flowing concrete is prepared, and the optimum water-cement ratio is obtained based on revised Bowromi formula. According to the mix proportion optimization design, the 28d strength of SSC is up to 38.5MPa.

Abstract: Based on the mechanism of reinforcement corrosion in concrete structures and the experimental measurements of corrosion potential and resistance, this paper investigates the impact of concrete cover thickness and chemical alkalinity on reinforcement corrosion. Experimental results show that the rate of reinforcement corrosion decreases as the thickness of concrete cover of reinforcement increases. Moreover, given no risk of alkali-aggregate reaction, raising the chemical alkalinity of concrete cover helps maintain passivation of reinforcement. Additionally, under general atmospheric conditions, cracks that are not along bars barely affect structural durability if the width of cracks is smaller than its standard limit.

Abstract: Through uniaxial compression test, tensile splitting test and bending test, we have researched the three kinds basic mechanical behaviors of Reactive Powder Concrete (RPC for short) with different steel fiber volume contents at 0%, 1%, 2% and 4% respectively. According to the result, the tensile splitting strength is a linear increase nearly with the increase of steel fiber volume content; and the bending strength is also increase with the increase of steel fiber volume content, When steel fiber volume content increases from 1% to 2%, the growing rate of bending strength reaches to maximum. When steel fiber volume content is within 4%, the compressive strength increases with the increase of steel fiber volume content. The compressive strength of plain RPC can reach to 135MPa, and the RPC with 4% steel fiber volume content is about 220MPa. This information can tell us that the addition of steel fiber in RPC can get an great increase of strength and toughness.

Abstract: With the increasing of industrialization, the heavy metals cause serious pollution of water in China. This paper reviewed the study of many kinds of new adsorbent materials remove heavy metal from pollution water, these new adsorbent including modification activated carbon, inorganic absorbent material, industrial waste, biological adsorbents and synthetic adsorbent, and pointed out the trend of development of the new adsorbent material application in the future.

Abstract: Along with the rapid development of highway, regenerated materials are used more frequently in highway engineering. Featured by low carbon and environmental protection, it confirms to the philosophy of sustainable development in China. However, the fast developing transport industry brings more heavy vehicles and heavy-load traffics take place commonly, thus causing diseases to China’s highway in advance. The major highway disease is wheel ruts. The appearance of wheel rut not only affects the service life of highway and the comfort level of driving, but also threatens driving safety, thereby causing huge losses and harmful effect. According to an investigation, 70% of highway suffers from the problem of wheel rut. High temperature and heavy load are two most important factors of wheel rut. This paper will take Tieling-Fuxin line for example to analyze the pavement performance and test the material performance of regenerated mixtures under different loads.

Abstract: It is known in the literature, at different temperatures bond strength bond between steel and concrete and relevant test data segment free end slip magnitude rarely, it is necessary to study this type of test, in order to more in-depth study of steel and variation between concrete bonding properties at different temperatures in order to verify different temperatures we derive between steel and concrete expressions are appropriate bond stress and slip. This test is primarily measured under different temperature conditions, reinforced concrete specimens under axial tension force central role, respectively, at the free end of the specimen and loading end bond segment relative slip steel and concrete at different temperatures . Because when the temperature reaches about 200 °C, the specimen began to appear on the adhesive debonding phenomenon, so this calculation is only done by experiments and theoretical consideration a temperature in the range of 20 °C to 190 °C.