Advanced Materials Research Vol. 739

Abstract: Portland cement, silica fume and superplasticizer were used to obtain high strength mortar with lower water to binder ratios and suitable binder to sand ratios. The splitting tensile strength and the rupture strength of the high strength mortar were improved further by a type of arc-shaped steel fiber when the content of steel fiber was 3-6.5 vol. %. The results indicated that the tenacity of the high strength mortar improved significantly by the steel fiber.

Abstract: Polycarboxylate was synthesized and the structure of the superplasticizer was characterized by FTIR. The water reducing effect of the synthesized copolymers was studied in terms of stirring time, the surface tension of superplasticizer and the adsorption on cement particles of superplasticizier. For all the samples tested in this research, increase in stirring time caused an increase in fluidity. The surface tension of the product solution (1wt%, w/w) is 51.2536 mN/m and the maximum value of adsorption was at about 2.6 mg/g at the concentration of 6wt%.

Abstract: concrete materials with low tensile strength, easy to crack, and the brittleness of the shortcomings in the polypropylene fiber concrete can improve performance. The compressive strength and flexural strength of the mechanical properties of polypropylene fiber reinforced concrete pilot study shows that the fiber content and curing age a great influence on the mechanical properties of polypropylene fiber reinforced concrete, the polypropylene fibers affordable dosage take1.5 percent is appropriate.

Abstract: The paper studied a compound desulphurization gypsum waterproof agent, which could modify the water-resistance performance of gypsum products on the basis of their microstructural properties. The waterproof mechanics were the synthesis results of superficial hydrophobic of hydrophobic emulsion, hindrance water of film forming matter and reducing the porosity in materials. The experiment results showed that the water-absorption rate of gypsum hardened body can be reduced to 3.5% and that the compressive strength reserve rate was 89.7% after 24h.

Abstract: In the design of base isolated structure, the parameter of seismic isolation layer is very important. At this problem, taking the reinforced concrete frame structure for example, using ANSYS software, the paper analyzed the dynamic characteristics of the base isolated structure, focused on the relation of the elastic stiffness of isolation layer and the isolation effects, and provided reference for reasonable selection of seismic isolation layer parameter.

Abstract: In order to determine the heavy plate structure have sufficient fracture toughness, based on BS7448 fracture toughness test experiment standard,the study of the typical bridge steel material were extended to CTOD( crack tip open displacement) fracture toughness test at 20 °C, The average CTOD value of base metal which was more than the allowable value of CTOD were obtained,so the structure can satisfy the design need .

Abstract: As a new kind of seepage control material, the geomembrane has been widely used in embankment dam, yet the seepage characteristics and effect of the geomembrane have not been studied on theory. Based on seepage mechanism in geomembrane, this thesis classifies the seepage into two types: one is permeability of geomembrane itself; the other is defect leakage flux in geomembrane. After studies respectively the influencing factors of permeability and defect leakage flux in geomembrane, the corresponding engineering measures were summed up. The study shows that the reasonable design and careful construction are requisite condition for the success of geomembrane seepage prevention works. At last, the philosophy of leak-position detection with electricity and its function in construction quality assurance was described.

Abstract: Since the three Gorges reservoir Water storage, reservoir water level have about 30m water levels fluctuation every year, different level will lead to the bank slope infiltration lines rise and fall, and influent on the bank slopes stability. The test according to Manzo reservoir laboratory test data and geological survey report, using the finite element software of ANSYS to establish the finite element model. The model put different water level decline speed, different osmotic coefficient and the different infiltration recharge tension cases to analysis separately,the result shows:1) more greater the reductions speed, more steeper the saturation lines luffing, more adverse the slopes stability;2) more smaller the permeability coefficient, more poor the slopes drainage capacity,more steeper the infiltration line, more poor the slopes stability; 3) seepage lines position higher than no infiltration seepage lines position.

Abstract: Large applications of pre-mixed mortar and the dwindling natural sand resources make people feel anxiety about the sustainable development of pre-mixed mortar, therefore, it is imperative to find replacement of natural sand. In this paper, several kinds of local tailings are selected. First, the basic performances of tailing sand are analyzed, then, the effect of the tailing sand on the performances of pre-mixed mortar are tested. The tests show that the mortar performance meets the technical requirements absolutely when tailings are used as aggregate mix mortar. When tailings substitute the natural sand, the mortar has qualified consistency and hierarchical degrees, but the strength is slightly lower. The natural sands are added to the limestone with more content of limestone powder which enrich the aggregate gradation, decrease the porosity of the aggregate and increase the fluidity. Also, both the consistency and hierarchical degrees of the mortar are very good. The tailings can be partially or completely substituted for the natural sand to mix the mortar, therefore, the exploitable yield of the natural sand can be reduced. The tailings are very suitable for mixing mortar.

Abstract: The paper deals with a statistical evaluation of the real material properties of weathering steels used for the construction of motorway bridges in the Czech Republic between 2001 and 2007. The statistical analysis and evaluation is carried out for a range of hot rolled plates made of S355J2W weathering steel. The paper contains an evaluation of the strength properties of the steel and its chemical composition. The paper also contains derived real values of partial factors of materials corresponding to the relevant reliability classes RC1 to RC3 pursuant to the European standard EN 1990.