Compressive Tensile Strength Research Articles

Characterization of green building materials manufactured from canola oil and natural zeolite

The main objective of this paper was to evaluate the feasibility and performance of building materials similar to gas concrete using epoxidized canola oil (ECO), fly ash (FA), natural clay (C) and natural zeolite (Z). In this study, ECO, C, FA [wastes produced in Afsin-Elbistan (Kahramanmaras, Turkey) thermal power station] and Z are used for producing building material. FA, C and Z were used as raw materials for producing the samples. ECO was used for binding. Density, thermal conductivity and compressive-tensile strength were decreased with the increase of ECO, FA and Z at all levels of replacements. Moreover, increasing process temperatures decreased density, thermal conductivity and compressive-tensile strength. Abrasion loss and water absorption were increased with the increase of ECO, FA, Z ratios and process temperatures.

Investigations into the tensile failure of doubly-convex cylindrical tablets under diametral loading using finite element methodology

In the literature various solutions exist for the calculation of the diametral compression tensile strength of doubly-convex tablets and each approach is based on experimental data obtained from single materials (gypsum, microcrystalline cellulose) only. The solutions are represented by complex equations and further differ for elastic and elasto-plastic behaviour of the compacts. The aim of this work was to develop a general equation that is applicable independently of deformation behaviour and which is based on simple tablet dimensions such as diameter and total tablet thickness only. With the help of 3D-FEM analysis the tensile failure stress of doubly-convex tables with central cylinder to total tablet thickness ratios W/D between 0.06 and 0.50 and face-curvature ratios D/R between 0.25 and 1.85 were evaluated. Both elastic and elasto-plastic deformation behaviour were considered. The results of 80 individual simulations were combined and showed that the tensile failure stress σt of doubly-convex tablets can be calculated from σt=(2P/πDW)(W/T)=2P/πDT with P being the failure load, D the diameter, W the central cylinder thickness, and T the total thickness of the tablet. This equation converts into the standard Brazilian equation (σt=2P/πDW) when W equals T, i.e. is equally valid for flat cylindrical tablets. In practice, the use of this new equation removes the need for complex measurements of tablet dimensions, because it only requires values for diameter and total tablet thickness. It also allows setting of standards for the mechanical strength of doubly-convex tablets. The new equation holds both for elastic and elasto-plastic deformation behaviour of the tablets under load. It is valid for all combinations of W/D-ratios between 0.06 and 0.50 with D/R-ratios between 0.00 and 1.85 except for W/D=0.50 in combination with D/R-ratios of 1.85 and 1.43 and for W/D-ratios of 0.40 and 0.30 in combination with D/R=1.85. FEM-analysis indicated a tendency to failure by capping or even more complex failure patterns in these exceptional cases. The FEM-results further indicated that in general W/D-ratios between 0.15 and 0.20 are favourable when the overall size and shape of the tablets is modified to give maximum tablet tensile strength. However, the maximum tensile stress of doubly-convex tablets will never exceed that of a flat-face cylindrical tablet of similar W/D-ratio. The lowest tensile stress depends on the W/D-ratio. For the thinnest central cylinder thickness, this minimum stress occurs at D/R=0.50; for W/D-ratios between 0.10 and 0.20 the D/R-ratio for the minimum tensile stress increases to 0.67, and for all other central cylinder thicknesses the minimum tensile stress is found at D/R=1.00.

Evaluation of mechanical properties of five cements for orthodontic band cementation

The aim of this in vitro study was to compare the flexural, compressive and diametral tensile strengths of five cements used in orthodontics for band cementation. Twelve specimens of each cement were tested: 1 - GC Fuji Ortho Band (FJ), GC America Inc.; 2 - Meron (MR), Voco; 3 - Multi-Cure Glass Ionomer Band Cement (MC), 3M Unitek; 4 - Band-Lok (BL), Reliance Orthodontic Products; and 5 - Ketac Cem (KC), 3M ESPE. The results (mean) for diametral tensile strength were: 10.51 MPa (FJ), 9.60 MPa (MR), 20.04 MPa (MC), 42.80 MPa (BL), and 4.08 MPa (KC). The results for compressive strength were (in the same order): 64.50 MPa, 77.71 MPa, 94.21 MPa, 193.88 MPa, and 81.93 MPa. The results for flexural strength were (in the same order): 20.72 MPa, 25.84 MPa, 53.41 MPa, 137.41 MPa, and 20.50 MPa. The statistical analysis was performed by two-way ANOVA and Tukey tests with p-value £ 0.05. In terms of diametral tensile strength, BL showed the highest strength statistically, and MC, the second highest. In terms of compressive tensile strength, BL showed the highest strength statistically, and FJ did not attain the minimum recommended strength. In terms of flexural tensile strength, BL cement was superior to MC, and MR, FJ and KC were equivalent and inferior to BL and MC.

Dynamic biaxial tensile–compressive strength and failure criterion of plain concrete

Dynamic biaxial tensile–compressive tests have been performed on dog-bone-shaped specimens of plain concrete under different tensile stresses and different strain rates, 100mm×100mm×100mm cubic specimens have been adopted in the tests of dynamic uniaxial compression. All tests have been performed by using the large static–dynamic true triaxial test machine. In the compressive direction, the friction-reducing pads have been used, which are made of three layers of plastic membrane with glycerin in-between. In the tensile direction, four bolts have been used to connect the specimen and loading head at the both ends of the specimen. The dynamic tensile–compressive strength, dynamic uniaxial compressive strength and dynamic ultimate compressive strain have been obtained in the paper. The failure modes of specimens have been described. The influences of strain rates and lateral tensile stresses have been discussed. The experimental results have been compared with the results of previous references, in which dynamic splitting tensile tests have been performed under the constant lateral compressive stress. By fitting the experimental data, the dynamic tensile–compressive failure criterion of plain concrete has been established. The dynamic failure criterion can provide the basis for analyzing concrete structural performances under dynamic tensile–compressive load.

Finite element prediction of surface strain and fracture strength at the distal radius

To better understand the mechanisms underlying distal radius fracture we have developed finite element models to predict radius bone strain and fracture strength under loading conditions simulating a fall. This study compares experimental surface strains and fracture loads of the distal radius with specimen-specific finite element models to validate our model-generating algorithm. Five cadaveric forearms were instrumented with strain gage rosettes, loaded non-destructively to 300N, and subsequently loaded until failure. Finite element models were created from computed tomography data; three separate density–elasticity relationships were examined. Fracture strength was predicted for three specimens that failed at the distal radius using six different failure theories. The density–elasticity relationship providing the strongest agreement between measured and predicted strains had a correlation of r=0.90 and a root mean squared error 13% of the highest measured strain. Mean absolute percent error (11.6%) between measured and predicted fracture loads was minimized with Coulomb–Mohr failure theory and a tensile–compressive strength ratio of 0.5. These results suggest that our modeling method is a suitable candidate for the in vivo assessment of distal radius bone strain and fracture strength under fall type loading configurations.

Property of High Volume Industrial Residue Concrete

To protect circumstance and improve of structure durability of Cao’e River floodgate, high volume industrial residue concrete (HVIRC) was prepared, and its mechanical property and durability were studied systematically. 10% of fly ash and 40% of ground granulated blast-furnace slag was used to replace 50% of cement in HVIRC. HVIRC had better anti-carking ability with larger tensile strength, larger ultimate tensile strain, larger tensile-compressive strength ratio and smaller elastic modulus-to-strength ratio. Dry shrinkage rate of HVIRC was similar with that of ordinary Portland concrete (OPC). HVIRC had higher compactness with smaller gas diffusion coefficient and relative permeability coefficient. Expansion caused by alkali-silica reaction reduced greatly by using high volume industrial residue and alkali-silica reaction was controlled markedly. HVIRC had better property of chloride ion penetration resistance with low effective diffusion coefficient. HVIRC could protect steel-bar from premature corrosions. Properties of sulfate resistance and frost resistance of HVIRC were also favorable. It’s proved that high volume industrial residue can enhance greatly mechanical property and durability of concrete and HVIRC can be used in Cao’e River floodgate.

Research of the Thermal and Strength Properties for Materials Obtained with Sunflower Oil

The use of pulverized fly ash (PFA) obtained from thermal power plants and epoxidized sunflower oil (ESFO) as recycled material in the construction industry was investigated. Epoxidized sunflower oil, clay (C) and pulverized fly ash were mixed at various proportions and were fired at 160, 180 and 200°C. The thermal conductivity and strength (compressive strength, tensile strength and abrasion loss) of the samples were determinated. The lowest value of thermal conductivity, 0.25 W/mK, was measured for the sample with a 70% FA/30% C ratio and 50% ESFO processed at 200°C. This sample had the lowest compressivetensile strength (3.28 MPa–0.633 MPa) and the highest abrasion loss (4.39%). The highest compressivetensile strengths and the lowest value of abrasion loss observed, were 7.21 MPa–0.939 MPa and 1.15%, respectively.

The effect of the rock type forming the aggregate in lightweight polymer concrete on compressive and flexural tensile strength

In this study, lightweight polymer concrete samples were produced with limestone (Ceyhan, Adana), pumice (Nevsehir) and zeolite (Gordes, Manisa) as a binder resin, and compressive and flexural tensile strength of these samples were determined via laboratorial experiments. For the study, the cylinder and prismatic samples of polymer on normal aggregate concrete (NAC), polymer on normal and lightweight aggregate mixture concrete (NLAC) and polymer on lightweight aggregate concrete (LWAC) were prepared. The polymer concrete produced was cured 3, 7, 28 and 90 days. The concrete samples were cured at 65% relative humidity with 20°C temperature. The density and slump workability of concrete mixtures were also measured. Laboratory test results showed that lightweight polymer concretes can be produced by the use of limestone, pumice, zeolite andas a binder resin. The use of mixture was recommended due to its satisfactory strength development. Key words: Polyester resin, compressive strength, flexural tensile strength, aggregate type, curing time.

Elastic-Plastic Analysis of the Interaction between Ice and Offshore Structures

In this paper, the mechanical properties of ice, which are affected by the existence of cavities and the different tensile-compression strength ratio, are analyzed in micromechanics view. Then the constitutive equation is established, and the distribution of stress field caused by the ice-structure interaction is constructed with the constitutive equation. Finally, the ultimate bearing capacity of ice is also discussed with different values of pressure sensitivity parameter and the tension-compression ratio. Thus, this paper provides the theoretical reference for offshore platforms design.

RELATİONSHİPS OF COMPRESSİVE STRENGTH WİTH TENSİLE STRENGTH AND E-MODULUS İN SELF COMPACTİNG CONCRETE

In this study, relationships of compressive strength with tensile strength and elastic modulus was investigated for self-compacting concrete (SCC) containing different types and dosages of mineral admixtures (fly ash (FA) and silica fume (SF)). Slump-flow, T50cm, L-box and sieve segregation tests were achieved for SCC mixes. In the following day of casting, the specimens were de-moulded and located in standard 20±20C water cured for the period of 28 days. Compressive strength, splitting tensile strength and elastic modulus tests were performed using a total of 3 specimens for each concrete property. Compressive–tensile strength and compressive strength-elastic modulus formulas obtained from regression analysis using a numerous data were compared with the equations of previous studies. Consequently, it was found that compressive strength-elastic modulus formula obtained from this study has almost estimated the elastic modulus of both normal and high strength self-compacting and other concretes, whilst compressive–tensile strength formula has correctly estimated the tensile strength of high strength self-compacting and other concretes.

Unified characteristics line theory of spacial axisymmetric plastic problem

The unified strength theory proposed by Yu in 1991 is extended to spacial axisymmetric problem. A unified spacial axismymmetric characteristics line theory based on the unified strength theory is proposed. This theory takes account of different effects of intermediate principal stress on yielding or failure and the SD effect (tensile-compression strength difference) of materials. Various conventional axisymmetric characteristics line theories, which are based on the Haar-von Karman plastic condition, Szczepinski hypothesis, Tresca criterion, von Mises criterion and Mohr-Coulomb theory, are special cases of the new theory. Besides, a series of new spacial axisymmetric characteristics fields for different materials can be introduced. It forms a unified spacial axisymmetric characteristics theory. Two examples are calculated with the new theory, the results are compared with those obtained by the finite element program UEPP and those based on the Mohr-Coulomb strength theory. It is shown that the new theory is reliable and feasible. The economic benefit can be obtained from the engineering application of the new theory.

Composite-to-metal tubular lap joints: strength and fatigue resistance

The axial strength and fatigue resistance of thick-walled, adhesively bonded E-glass composite-to-aluminum tubular lap joints have been measured for tensile and compressive loadings. The joint specimen bonds a 63 mm OD aluminium tube within each end of a 300 mm long, 6 mm thick E-glass/epoxy tube. Untapered, 12.5 mm thick aluminium adherends were used in all but four of the joint specimens. The aluminum adherends in the remaining four specimens were tapered to a thickness of 1 mm at the inner bond end (the bond end where the aluminum adherend terminates). For all loadings, joint failure initiates at the inner bond end as a crack grows in the adhesive adjacent to the interface. Test results for a tension-tension fatigue loading indicate that fatigue can severely degrade joint performance. Interestingly, measured tensile strength and fatigue resistance for joints with untapered adherends is substantially greater than compressive strength and fatigue resistance. The joint specimen has been analyzed in two different ways: one approach models the adhesive as an uncracked, elastic-perfectly plastic material, while the other approach uses a linear elastic fracture mechanics methodology. Results for the uncracked, elastic-plastic adhesive model indicate that observed bond failure occurs in the region of highest calculated stresses, extensive bond yielding occurs at load levels well below that required to fail the joint, and a tensile peel stress is generated by a compressive joint loading when the aluminum adherends are untapered. This latter result is consistent with the observed joint tensile-compressive strength differential. Results of the linear elastic fracture mechanics analysis of a joint with untapered aluminum adherends are also consistent with the observed differential strength effect since a mode I crack loading is predicted for a compressive joint loading. Calculations and a limited number of tests suggest that it may be possible to selectively control the differential strength effect by tapering the aluminum adherends. The effect of adherend material and thickness on fracture mechanics parameters is also investigated. The paper concludes by examining the applicability of linear elastic fracture mechanics to the joints tested.

Size Effects in Model Concretes?

The paper reviews current research on the effect of specimen size on compressive, indirect tensile and flexural tensile strengths, the stress-strain characteristics, and related quantities. The measured compressive and tensile strengths were observed to increase with a decrease in specimen size in all investigations. The nondimensional stress-strain curves in compression tests were noted to be homologous for prototype and model concretes. A higher tensile-compressive strength ratio is observed in smaller specimens. The effects of duration and conditions of curing compactions, shape of specimen, and other factors are reported. Techniques are suggested to select the cylinder size to evaluate the concrete compressive strength in a model specimen. To assist with the determination of size effects and standardization, the ACI Committee 444 on Models of Concrete Structures has recommended that model investigations should include compression tests on 2-in.x4-in. (50-mmx100-mm) cylinders along with any other cylinder sizes used.