Weiqiang Zhang

• China University of Mining and Technology

Previous researchers have shown that the Katz–Thompson theory is useful in predicting permeability of sedimentary rock from mercury intrusion porosimetry data. In this paper, the variations in pore characteristics of sandstone and limestone in the temperature range of 25 °C–600 °C are studied based on mercury injection test and the permeability evo...

Clay is a vital industrial raw material, and its physical and mechanical properties undergo significant changes when heated at high temperatures. A good understanding of those properties can provide details on the best use of clay, and may eventually facilitate new application areas. In this paper, the physical and mechanical properties of clay aft...

In this paper, thermal shock experiments at different temperatures and cycles were carried out on red sandstone. Its surface properties, including color and roughness, were systematically studied. The results show that the color change of sandstone is mainly related to two compositions: one is goethite, the other is calcium carbonate (CaCO3). The o...

Temperature significantly affects the physical and mechanical properties of granite. To have a comprehensive understanding of the thermal cycle effect on uniaxial compressive strength ( UCS ) and thermal damage rate, a series of thermal cycle experiments on granite specimens were carried out with five types of designed temperatures and five types o...

Variations in wave velocity and porosity of sandstone after high-temperature treatment are investigated. The results for normalized wave velocity and porosity show that 400 °C is the critical threshold temperature of sandstone. Below 200 °C, porosity increases slowly as the treatment temperature increases, while wave velocity gradually decreases. W...

To quantify the damages caused by thermal cycles, the chromaticity, P wave velocity, thermal conductivity and tensile strength were measured on diorite samples subjected to different heating/cooling cycles at different temperatures. The mechanism is analyzed based on dehydration, tensile stress and phase changes of the quartz mineral. It is found t...

The study on radon emanation and exhalation in soil is more and more important for environmental protection, and many influencing factors on radon emanation coefficient and exhalation in soil have been well documented. In order to evaluate the radon change and key influencing factors, this paper made an overall summary based on these studies. The m...

In determining the physical and mechanical parameters of clay, it is sometimes necessary to determine them indirectly from other parameters since they cannot be measured directly from laboratory or field tests. In order to determine the effect of temperature on the behavior of clay, an indirect approach is used here by analyzing the changes of mass...

Understanding the properties of concrete under load is essential for assessing the stability and serviceability of buildings. In this work, the uniaxial compression test of concrete was carried out based on acoustic emission (AE) in order to monitor the dynamic damage of concrete in real time and study the failure mechanism. The change of AE energy...

In this study, the rate of emission of arsenic during the burning process of different kinds of coal is examined in order to study the volatile characteristics of arsenic during coal combustion which have negative effects on the ecological environment and human health. The results show that the emission rate of arsenic gradually increases with incr...

This work analyzes the results from experiments for studying the effect of high temperature on primary wave velocity of granite. Test samples are preheated to different temperatures (from 25° to 900 °C) and then cooled down by air. The primary wave velocity test is performed on the heated samples. Lastly, the microstructure test is carried out to s...

In order to study the effect of thermal damage on the electrical property of sandstone, an electrical resistivity test is carried out with an electrical instrument. The prepared cylindrical samples are successively heated to target temperatures (i.e. 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, 700 °C and 800 °C) at a fixed slow rate and gradual...

Heating at high temperature will make the tensile strength of sandstone change due to the loss of water and minerals and the effect of thermal stress. In this paper, the sandstone samples are heated from room temperature to 900 °C in a high temperature furnace and then are subjected to Brazilian test with a computer-controlled hydraulic universal t...

Rainfall is one of the important factors causing the failure of slope, such as the occurrence of transverse cracks and localized slumps. The process of rainfall seepage was studied with an indoor soil slope model based on the Network Parallel Electrical Method. The responses of geoelectric-field parameters were analyzed to infer the evolution proce...

This paper studies the variation of mass, density, wave velocity and thermal conductivity of concrete after high-temperature heat treatment. The range of temperature to which the concrete specimens are exposed is 25–900 °C, in a heating furnace. The results are summarized as follows: three temperature ranges (20–300 °C, 300–600 °C and above 600 °C)...

In order to study the effect of high temperature on the sandstone, scanning electron microscope (SEM) experiments and primary wave (P-wave) velocity tests have been carried out on sandstone specimens heated to different temperature. The results showed that: (1) the mass loss rate increases exponentially with the increase of temperature and reaches...

This paper experimentally studied the changes in mechanical and porous characteristics of limestone heated to high temperature (up to 600 °C). The results showed that ① 200 °C and 500 °C are two special temperature point of limestone under the high temperature effect, and the most mechanical and pore parameters change a lot before and after them; ②...

This paper experimentally studies the variation of pore characteristics and mechanical properties of sandstone at different temperatures (from 25°C to 600°C). The results show that the sandstone samples mainly have holes with diameters between 0.7μm and 3μm and at threshold diameters of 0.01μm and 3μm, the cumulative pore volume changes drastically...

This paper reports the variations of strength, resistivity and thermal parameters of clay after high-temperature heating. Experiments were carried out to test the physical properties of clay heated at temperatures ranging from room temperature to 800°C in a furnace. The experiment results show that below 400°C the uniaxial compressive strength and...

This work discusses an experimental investigation on the thermal damage characteristics of limestone and underlying mechanism. Cylindrical rock samples were heated to a specific temperature level of 25, 100, 200, 300, 400, 500, 600, 700, 800, and 900 °C. Then the thermal damage evolution equation was established based on the experimental results an...

In order to investigate the effect of high temperature (25–800 °C) on mechanical properties of concrete, uniaxial compression test is carried out to study the relationship between compressive strength and temperature, and the crack development in concrete specimen is monitored based on the acoustic emission (AE) phenomenon to reflect the change of...

This paper reports the variations of mass, porosity, and wave velocity of sandstone after high temperature heating. The range of temperature to which the sandstone specimens have been exposed is 25-850°C, in a heating furnace. It has been shown that below 300°C, porosity and wave velocity change very little. Above 300°C, there is a rapid increase i...

This paper reports the variations of thermal conductivity, thermal diffusivity and heat capacity of sandstone after high-temperature heating. Experiments were carried out to test the thermal properties of sandstone which had been heated at temperatures ranging from room temperature to 900 °C in a furnace. Temperature has a significant impact on the...

High temperature thermal treatment to clay mineral often leads to the development of new micro-cracks or extension/widening of pre-existing micro-cracks, which naturally would result in the variation of physical properties. Experiments aiming to understand the evolution of physical properties of clay have been carried out from 20 to 800 °C in a hea...

The changes of mineral components, internal structure and water content of the rock after heating lead to the variation of the physical and mechanical properties. This paper aims to study the thermal effect (from 25 °C to 500 °C) on physical and mechanical properties (such as mass, density, porosity, P-wave velocity, compressive strength, peak stra...

To study the effect of high temperature on the microstructure and velocity of primary wave (P-wave) propagation in rocks, scanning electron microscope (SEM) experiments, mercury injection experiments and P-wave velocity tests were conducted on limestone samples which had been heated at high temperature (from 25 to 900 °C), and then the variations o...