Papers by Keyword: Splitting Tensile Strength

Abstract: Tests on the Indonesian coconut fiber showed that, compared to the results of previous studies, tensile strength and tension failure improved after the fiber was washed with water and dried. This study aims to obtain the effects of fiber length and fiber content on splitting tensile strength behavior of the concrete composite reinforced with coconut fiber. Experimental observations were carried out on the splitting tensile strength of coconut fibers as determined by the fiber content (1, 2, 3, and 4 % by a mass ratio of fiber per cement) and the length of the fibers (5, 20, 40 mm) in the concrete. The results show that a coconut fiber length of 5 mm and a fiber content of 3 % in fiber concrete composite gives the composite 1.28 times higher splitting tensile strength than plain concrete. The density of the fiber concrete composite decreases with the addition of coconut fiber content.

Abstract: The adverse environmental impact of the construction industry may be mitigated through the partial replacement of cement with supplementary cementitious materials (SCM). SCMs such as ground granulated blast furnace slag (GGBS), impart many favourable fresh and long-term concrete properties. A study by Mohamed [1] assessed the splitting tensile strength of sustainable self- consolidating concrete in which up to 80% of the cement was partially replaced with ground granulated blast furnace slag (GGBS), and developed a prediction formula for the splitting tensile strength. In this paper, the tensile strength prediction formula developed by Mohamed et al. [1] is benchmarked against formulas proposed in different building codes and validated with additional test results obtained from the literature. The proposed prediction formula showed excellent correlation to experimental data obtained from the literature.

Abstract: The American Concrete Institute (ACI) code of concrete design ACI 318, and many other concrete codes report expressions for estimating splitting tensile strength as a function of the specified concrete compressive strength. However, for self-consolidating concreate, research is still needed to develop reliable expressions for the prediction of splitting tensile strength. Mohamed et al. [1] proposed an expression for splitting tensile strength of sustainable self-consolidating concrete in which cement was partially replaced with fly Ash, silica fume, and ground granulated blast furnace slag (GGBS). This paper presents validation of the splitting tensile strength expression using additional test data in which concrete mixes were prepared using various water/cement ratios. expression developed by Mohamed et. al. [1] exhibits excellent correlation with test data as demonstrated in this paper.

Abstract: This paper describes approaches to evaluating the resistance of cement-based composites to sulphate attack. The conventional approach of evaluation by means of measuring expansion is discussed in comparison with the sulphate diffusion, which was quantified as a function of depth. Besides CSA Types GU and HS, a 30:70 blend of fly ash and cement Type GU was also examined. The specimens so produced were immersed in a sulphate solution as per ASTM C1012 and retrieved variously after 7, 14, 28, 56 and 84 days of exposure. As expected, Type HS cement performed best with minimum expansion and sulphate ingress. On the other hand, the Type GU cement showed lower expansion and sulphate ingress in comparison to the fly ash blended binder. Although bearing identical porosity, the blended binder had the smallest median pore size. Therefore, the sulphate ingress and consequent ettringite production likely cracks the blended system more than the other two. Significantly, after longer durations of sulphate exposure, the blended system showed higher tensile strength which implies a healing of cracks through ettringite formation.

Abstract: Siliceous concrete (SC) is applied in European Pressurized Water Reactor that is a key component of the third generation nuclear power plant. This paper investigates the mechanical properties and damage evolution of SC (with and without polypropylene fibers) exposed to high temperatures. The mass loss, compressive strength, splitting tensile strength and spalling sensitivity of SC before and after being heated to 200, 400, 600, 800, and 1000 °C are investigated. The ultrasonic testing technique was used to assess the thermal damage, by evaluating the variations of the ultrasonic wave velocity (UWV) for different temperature levels. According to the available literature, a new relationship between damage and UWV was proposed to establish a damage evolution model of SC. The results indicated that: (a) specimens without polypropylene (PP) fibers suffered severe spalling in the range 380-400°C and 470-510°C, while no spalling took place in the specimens with PP fibers in the whole range 25-1000°C; (b) the damage evolution with and without polypropylene fibers was similar, and could adequately be described by means of a Weibull distribution model.

Abstract: The effect of graphite oxide (GO) on the mechanical properties of oil well cement was experimentally studied, in view of the zonal isolation failure due to the brittleness. The microstructure of cement stone was observed by SEM, and the mechanism of graphite oxide reinforced cement stone was also investigated. The result illustrates that the mechanical properties of cement was improved significantly due to the addition of GO. When the GO dosage was 0.05%, the compressive strength, flexural toughness, and splitting tensile strength of cement paste at 7 day age were increased by 61.32%, 15.46% and 145.34% respectively. GO had no bad effect on the application properties of cement slurry, and the stability of the slurry was favorable. Besides, GO could reduce the fluid loss of cement slurry. When GO reinforced cement stone undergoes damage under complex stress, if damage occurs within graphite oxide layer, chemical bonds of GO layers must have been broken, and the force between the layers of GO must be overcome when interlaminar peeling happens, which will lead large amounts of energy consumption as well. The mechanical properties of the cement stone were enhanced by the above two aspects. The research results can provide a theoretical reference for solving the brittle fracture of oil well cement stone.

Abstract: Polymer resin grout can be used as bonding material for grouted sleeve connections This paper presents the experimental results on the effectiveness of fly ash as micro filler to the splitting tensile strength of polymer grout. In addition, the cement grout that is usually used as bonding material had been tested for comparison. Eleven proportions, of fly ash as the filler and polymer as binder, were tested with the binder to filler volume ratios of 1:1 and 1:1.5. The test results revealed that fly ash can be used as a micro-filler material to partially replace ordinary river sand in polymer resin grout. The splitting tensile strength of the polymer grout increases with the increase of fly ash contents. However, for higher level of fly ash of more than 22%, the splitting tensile strength deteriorated. For binder: filler ratio of 1:1, the optimum fly ash content of 22% gave the maximum splitting strength of 17.62 MPa, which can be considered acceptable for producing grout with high strength bonding material.

Abstract: In order to realize the recycle of waste tires, rubber concrete can be utilized in road engineering. The bond property of interface between rubber concrete and matrix ordinary concrete is one of the key factors. This paper studied the interfacial bond property by splitting tensile strength test and shear strength test and considered several influence factors, such as rubber volume fraction, rubber particle size, interfacial roughness and curing time of matrix concrete. The results show that the shear strength decreases with the increase of rubber content, longer curing time of matrix concrete, and the larger size of rubber particle. The splitting tensile strength also deceases with the longer curing time of matrix concrete or smaller interfacial roughness. However, no regular relationship is found between the splitting tensile strength and the size of rubber particle or rubber volume content.

Abstract: Designing recycled concrete mixture proportion of different recycled coarse and fine aggregate replacement content by pulp content ,then testing compressive strength and splitting tensile strength. The text results show that: With the increasing of recycled aggregate content , the compressive strength and splitting tensile strength of recycled aggregate concrete trended to decrease. Compared to recycled coarse aggregate, recycled fine aggregate impact on the properties of recycled concrete is greater. Establishing the compressive strength and splitting tensile strength formula of recycled concrete based on a lot of experimental results.

Abstract: This paper reports an investigation on mechanical properties of high volume fly ash (HVFA) concrete produced using different types of mixing water i.e. tap water and saturated lime water. The mechanical properties of ordinary Portland cement concrete are also investigated as control tests. The concrete were tested for their compressive strength, flexural strength and splitting tensile strength at the curing ages of 56 days. The results showed that strength development of high volume fly ash concrete up to 56 days is lower than ordinary portal cement. In addition, the flexural strength and splitting strength of concrete are lower than ordinary Portland cement. Moreover, the use of saturated lime water as mixing water reduces the mechanical properties of class C high volume fly ash concrete.