Applied Mechanics and Materials Vols. 357-360

Abstract: Wood, a potentially good construction material in terms of sustainability, has less structural use now in India. Due to easy availability, low cost and good working quality there is a scope for the value addition of rubber wood in the Country. Finger jointing technology benefits high economic advantage by upgrading rubber wood. There is a dearth of information for the influence of adhesive on the mechanical properties of jointed rubber wood in India. This study was conducted to evaluate the effects of adhesive type on the end jointing and face gluing of rubber wood. The end jointing adopted for the study was the most common finger joint configuration of the wood industry in Kerala, the largest producer of rubber wood in the Country. The adhesives were polyvinyl acetate (PVAc) and phenol resorcinol formaldehyde (PRF). The face gluing evaluation was done based on the adhesive bond strength and percentage wood failure. The integrity of glue types to delamination was also tested .The results of the study have indicated glue type has no statistically significant effect on modulus of rupture, modulus of elasticity of finger joints and the shear strength of adhesive bond in the dry stage with the same wood failure percentage. The joint efficiency of PRF adhesive was superior to PVAc in tension and compression of finger joints. The PRF adhesive exhibited excellent performance in the exterior exposure condition durability test.

Abstract: A series of tests were conducted with laboratory normal devices to investigate the engineering property of coal ash mixed with various clay contents. By analyzing experimental data, some conclusions were made: It is helpful to improve the compaction effect and significantly reduce the consumption of the water needed in engineering by mixing the clay into coal ash. The shear strength of coal ash decreased slightly with increase of clay content. The shear strength of coal ash mixed with the 30% clay content is nearly equal to that of pure coal ash. With the increase of clay content, the coefficients of compressibility a_1-2 have a little irregularly growth. It always belongs to medium compressibility soils.

Abstract: The shear tests were made on 18 different groups of deep beams with steel fiber and polypropylene fiber according to the orthogonal experimental design. For comparison, 2 groups of high performance concrete deep beams without fiber were conducted. Shear ductility and deformation performance of deep beams were analyzed quantitatively. Results illuminate that failure mode of high performance concrete shear deep beam is splitting failure, while hybrid fiber reinforced HPC shear deep beam has two failure modes (splitting failure and diagonal compression failure). The mixing of hybrid fiber makes rigidity of HPC deep beam increase obviously, the strain of web horizontal reinforcement and web vertical reinforcement decrease significantly. The catastrophe of strain of cracked concrete is also obviously smaller and the descending step of loaddeflection curve is flatter when adding hybrid fiber. Hybrid fiber can greatly increase shear ductility of deep beams and shear ductility is at the most increased by 40.7% whereas it can not change the brittleness of shear damage radically. The volume fraction of steel fiber plays the most important role in shear ductility whereas the shape of steel fiber has minimum effect among analyzed six factors.

Abstract: The paper presents an test and computational results of finite element studies on the behavior and capacity of abnormal exterior joints of Steel Reinforced Concrete (SRC) column and Reinforced Concrete (RC) beam. The critical parameters influencing Anti-Shear Capacity are analyzed by ABAQUS, such as the eccentricity of column section, the steel ratio of the joint core zone, the concrete strength and the axial compression ratio and so on. As a result, the Anti-Shear capacity of the joints mainly depends on “the minor joint zone”. The calculating formula of Anti-Shear capacity of the joints, with the computing unit of minor joint core zone, is deduces.

Abstract: In recent year, Korea relies on imports for most of the iron ore, the main raw material of rebar, resulting in CO₂ pollution with lots of energy consumption. Hereupon, this study carried out the research on the energy consumption and CO₂ emissions of the recycled rebar using the wasted steel from building demolition. For that, this study worked out the energy consumption and CO₂ emissions in the process of generation, transportation and production of wasted steel and, on the basis of which, it conducted the comparative study with virgin materials. The major research results are as follows: First, the energy consumption and CO₂ emissions of the recycled rebar were found to be highest in the process of its production at 89.2% and 85%, respectively. In addition, in the comparison between recycled rebar and virgin material, the former was found to be most advantageous in energy consumption. On the contrary, as for CO₂ emissions, the recycled rebar showed a 88.3% reduction possibility of greenhouse gas (GHG) emissions comparing to statistics of input-output analysis based on competition inducement coefficient, but it was found to be more disadvantageous from the perspective of GHG reduction than the statistics of input-output analysis based on non-competition inducement coefficient.

Abstract: Corrosion of steel constructions due to the affection of aggressive agents is one of the principal problems affecting reinforced concrete constructions. In critical cases, this phenomenon may cause static destabilisation of the construction and as a result, it is necessary to protect constructions using primary and secondary protection which significantly decreases this risk. This paper addresses the options for evaluating various types of protective anti-corrosion systems which use progressive corrosion inhibitor technology in a laboratory environment. Corrosion inhibitors efficiently slow down the course of corrosive processes on steel reinforcement and prolong the service life of building constructions. The rate of efficiency can be verified with high information capability in the laboratory by a series of testing methods.

Abstract: To predict bearing capacity on mortar-rock interface of compression type rock anchor, the failure model of fixed anchor length is established. The maximal shear stresses on the interface in front of the bearing plate are determined based on tests. The relation of maximal shear stress and fixed anchor length is assumed. Double exponential function curves are adopted to simulate the ultimate state of the fixed anchor length. Two parameters are introduced to adjust the curve shape. According to the results of the field test, the values range of the parameters in soft rock is determined. After comparing ultimate bearing capacity measured in test with predicting value, it is shown that the empirical formula can calculate the bearing capacity of fixed anchor length reasonably. Compression type rock anchors have more capacity than ordinary tension type anchors and the capacity is convergent gradually with fixed anchor length increase.

Abstract: Related to temperature control measures and material parameters, crack prevention by temperature control in quasi-mass concrete is an optimization problem including multiple complicated factors. This study tries to do some optimization of temperature control measures in the given concrete thermodynamics parameters circumstance. The quasi-mass concrete structure’s minimum value of the relationship between principal tensile stress duration curves of internal and surface and the tensile strength growth curve are taken as the input, and the gate pier surface heat preservation effect, pouring temperature, water cooling temperature, water cooling time are taken as the output, we establish the optimal temperature control measures by the neural network model. Applying the uniform design principle to combine the temperature control parameters, and using the finite element method to analyze the temperature field and creep stress field in the quasi-mass concrete structure containing cooling water pipes, we obtain the samples, for training the network, to describe the nonlinear relationship between the principal tension stress duration curve and the tension strength growth curve and the different temperature control measures. After inputting the fitting minimum value of relationship between the principal tension stress duration curve and the tension strength growth curve to the trained network, the system is able to automatically select the optimal temperature control measures for crack prevention. The example shows that the proposed optimal neural network model for temperature control measures is feasible.

Abstract: Based on the research and indoor experiments, this paper investigates the mixing and curing techniques, pavement performance, and influencing factors of emulsified asphalt cement concrete. The results indicate that mixing sequence of raw material and curing condition have great impact on the strength of the mixture. Adding cement to mixture can improve the pavement performance of mixture greatly. However, increasing the content of emulsified asphalt has opposite effect. Proper content of emulsified asphalt will ensure the bonding strength and waterproof property of the mixture. The critical factors that influence the pavement performance of emulsified asphalt cement concrete are asphalt cement ratio, water cement ratio, content of emulsified asphalt and cement, sand percentage, and aggregate gradation.

Abstract: The interception products of vanadium processing as vanadium alloys were studied in producing vanadium-containing seismic resistant rebar. The experimental results show that vanadium alloying with intermediate products was feasible and low-cost. Compared with conventional production process or ferrovanadium alloying, applied vanadium slag alloying in producing HRB335E could save 12.45 RMB per ton of steel, applied vanadium ball alloying in producing HRB400E could save 21.23 RMB per ton of steel, applied V-iron alloying in producing HRB400E could save 11.06 RMB per ton of steel.