Advanced Materials Research Vols. 535-537

Abstract: Keywords: Boron carbide, concrete, shielding, neutron, attenuation. Abstract. Boron carbide (B4C) is a ceramic material which is effectively absorb thermal neutron due to wide neutron absorption cross section. In this work, B4C is added into concrete as fine aggregates to test the attenuation properties by getting the attenuation coefficient of the concrete/ B4C. The samples of concrete/ B4C were exposing to the thermal neutron radiation source (241-Americium-Berylium) at the dose rate of 29.08 mR/h. The result show that the attenuation coefficient of the sample with 20wt% B4C is 0.299 cm-1 and the sample without B4C is 0.238 cm-1 and hence, concrete/ B4C is suitable as a shielded for thermal neutron radiation.

Abstract: In Mexico, since the early stages of the civilization, the stone masonry has assumed an important role in construction due to the wide availability of this kind of material. Masonry is a material composed by bricks, carved or even rubble stones jointed without (dry joint) or with mortar (mortar joints); which is principally formed with sand, water and cementitiuos materials. The research presented in this paper deals with the procedure of obtaining the mechanical properties of rocks placed on piers of four vehicular bridges located in the south of the state of Mexico, these mechanical properties are compressive strength, modulus of elasticity, Poisson ratio, Cohesion and Internal friction Angle of the rocks as independent units, also are reported the Density values. All of these properties are necessary to conduct further research regarding the mechanical behavior of the pier as a structure since this piece of research is part of an ongoing project concerning risk assessment of vehicular bridges developed in Mexico. The identified rocks in masonry were volcanic igneous materials such as dacites, basalts, rhyolites, andesites and rusted andesites. The materials with the highest and the lowest mechanical properties are the basalt and the dacite respectively. It is recommended to use the dacite’s properties in order to perform a conservative analysis of the mechanical behavior of any masonry structure, located near the selected sample studied herein.

Abstract: Ultra High Performance Fibre Reinforced Concrete (UHPFRC) is a cement-based material, which behaves like a low-porosity ceramic material with excellent mechanical performance. This work was aimed to study soft cast (flowable at casting time) UHPFRCs and, in particular, UHPFRC mechanical performance was monitored by means of compression, bending and splitting tension tests. Two different kinds of mineral addition were compared: silica fume and fly ash. In the case of fly ash, several water to cement ratios were tested ranging from 0.20 to 0.25. Moreover, steel fibers and acrylic-based superplasticizer were employed to prepare the UHPFRC mixtures.

Abstract: This article researches the newly emerged architectural skin materials such as ETFE membranous material, paper, fabric, plastic, mental tapping board and mental weaving net, printing glass and colored glass, and various special materials. It analyses their characters and impression effects in architecture.

Abstract: In this paper, the mineralogical characteristics of Brazil kaolinite and Beihai kaolinite have been researched. The structure and performance of samples were systematically analyzed by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electron microscopy (TEM).The results showed that Brazil kaolinite had inerratic pseudo-hexagonal morphology, low diameter-thickness ratio and a Hinckey index of 1.501. While Beihai kaolinite has irregular-polygonous morphology, higher diameter -thickness ratio and a Hinckey index of 1.197. The differences in structural make them have different physical properties.

Abstract: Concrete is the most widely used building material and due to its use, water tightness is one of the factors essential for many constructions. Materials applied on concrete surface as secondary protection can have various forms. One of the material group with waterproofing ability, are materials on so called "crystalline technology base". As this material is cement-based its wide world production brings significant effect on environment. To bring on building materials market new materials should be considered its environmental friendlier production. One of the ways for this group of materials with crystalline abilities is replacing cement by other substituent, at best by secondary raw material. This would bring double advantage, lowering usage of cement and on the other hand use of already produced secondary raw material. This article deals with new developed materials based on "crystalline technology" with cement partly replaced by fly-ash substituent. At this article are presented results of new developed screed and coating modifications and its effectiveness on concrete waterproofing.

Abstract: Abstract: In view of the mass brittle failures of reinforced concrete construction in Whenchuan earthquake, the ductility of construction was selected to be the research object. A group of the cyclic-loading experiment was carried out on seven shear-and-pressure concrete columns which mixed with different fiber types and various volume content, but same cross-section and reinforcement. In the process, the load-displacement curves of the columns were attained and the skeleton curves accordingly were drawn, together with the key values in various stages. Based on these, an analysis on various factors which affect the ductility of the columns is conducted. The results show that the ductility of columns is improved significantly and the appearance of plastic hinge is delayed, which are likely to avoid the occurrence of brittle failure in earthquake. The experimental result indicates the steel fiber-strengthening concrete possesses the strongest energy dissipation capacity, the carbon fiber improve ductility of the column, and the synthetic fibers can effectively delay emergence of the plastic hinge, but a lesser extent to improve the shear capacity of the column.

Abstract: In response to the requirement of saving 65% energy in hot summer and cold winter zone, a comprehensive comparative analysis has been conducted in various aspects towards the common organic and inorganic thermal insulating materials in the market. And a conclusion has been drawn that, on the basis of reaching the standards, inorganic thermal insulating materials represented by aluminum sulfate boast obvious advantages compared to organic ones in terms of fire proofing, durability, economical efficiency, and environmental protection etc. Thus, the inorganic thermal insulating material will become the first choice in future market.

Abstract: In order to study the feasibility that whether the all-lightweight aggregate concrete slabs can be the structural member， we test on 6 pieces of all-lightweight aggregate concrete slabs. The flexural behaviors of all-lightweight aggregate concrete slabs which have the same intensity level and section size is analyzed comparatively under the same mode of action， but different reinforcement situation. The result shows that the all-lightweight aggregate concrete slab has certain bearing capacity and deformation capacity. It can replace the ordinary concrete slab as load-bearing member. The experimental study in the paper can provide a basis of the lightweight and energy-saving multi-story structure.

Abstract: The velocities of shear waves propagating along radial direction of birch and elmwood specimens are measured in order to study the effect of anisotropy on shear wave velocity. The relationship between the shear wave velocity and the oscillation direction is examined by rotating an ultrasonic sensor. The results indicate that the effect of anisotropy on shear wave velocity in birch and elmwood specimens is similar to Japanese magnolia specimen. When the oscillation direction of the shear wave corresponds to the certain anisotropic direction of the wood specimen, the shear wave velocity decreases sharply and the relationship between shear wave velocity and rotation angle tends to become discontinuous. The intrinsic birefringence due to the anisotropy of birch and elmwood woods is observed. Their texture anisotropies are strong. In an isotropic nylon, on the contrary, the value of shear wave velocity was similar to a circular ring. This investigation is significant meanings in architectural and civil engineering field.