Experimental Study on Dynamic Mechanical Properties and Energy Evolution Characteristics of Limestone Specimens Subjected to High Temperature

Abstract

To study the effect of high temperature on the dynamic mechanical properties and energy evolution characteristic of limestone specimens, the basic physical parameters of limestone specimens that cool naturally after experiencing high temperatures of room temperature (25°C), 200°C, 400°C, and 600°C were tested. In addition, compression tests with 6 impact loading conditions were conducted using SHPB device. The changes of basic physical properties of limestone before and after temperature were analyzed, and the relationship among dynamic characteristic parameters, energy evolution characteristics, and temperature was discussed. Test results indicated that, with the increase of temperature, the surface color of specimen changed from gray-black to gray-white, and its volume increased, while the mass, density, and P-wave velocity of specimen decreased. The dynamic compressive stress-strain curve of limestone specimens after different high-temperature effects could be divided into three stages: elasticity stage, yield stage, and failure stage. Failure mode of specimen was in the form of spalling axial splitting, and the degree of fragmentation increased with the increase of the temperature and incident energy. With the increase of the temperature, the reflection energy, the absorption energy, the dynamic compressive strength, and dynamic elastic modulus of rock decreased, while its transmission energy, the dynamic peak strain, and strain rate increased. The dynamic compressive strength, dynamic elastic modulus, dynamic strain, and strain rate of limestone specimens all increased with the increase of incident energy, showing a quadratic function relationship.

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

“…The dynamic mechanical properties of rocks under hightemperature circumstances have caused scholars' widespread concern. Nevertheless, due to the limitation of test conditions, the majority of scholars adopted the test method that the sample was heated before the implementation of the SHPB test, in the early research [5,6]. Macroscopically, when the temperature was fixed, the dynamic peak strain and strength of rock increased with the increase of the strain rate, which was basically similar to dynamic response characteristics of rocks at room temperature [7].…”

“…The change of macroscopically mechanical characteristics is closely related to the variation of physical properties of rocks. Research shows that temperature plays a significant role in physical properties of rocks, such as reducing density [9,10], increasing porosity [11][12][13], and reducing longitudinal wave velocity [14,15], which is an essential reason for the variation of mechanical characteristics [6,16]. In addition, the material composition and microstructure characteristics of rocks after thermal treatment were systematically studied by microstructure observation methods, such as X-ray diffraction [17] and SEM scanning [18,19].…”

Dynamic Mechanical Properties and Energy Dissipation Analysis of Sandstone after High Temperature Cycling

“…e strain gauge test usually uses the testing principle of Wheatstone bridge. e two strain gauges were symmetrically pasted on both sides of the pressure bar and placed on the same cross section of the pressure bar to avoid the influence of the pressure bar bending on the test data and eliminate the interference signal of the nonaxial strain [22]. Based on the basic principle of SHPB test [23], the dynamic strength, dynamic strain, and dynamic elastic modulus of sandstone samples after high temperature cycle were analyzed by using the three-wave method.…”

Experimental Study on Physical and Dynamic Mechanical Properties of Temperature‐Water Coupled Sandstone

“…Split Hopkinson pressure bar (SHPB) device is the most commonly used loading device in the study of rock dynamic physical and mechanical properties. Ping et al [12][13][14][15] analyzed the variation rule of the dynamic stress-strain curve of sandstone under a high temperature of 25°C to 1000°C. In addition, the effects of temperature on dynamic compressive strength, dynamic peak strain and strain rate, dynamic elastic modulus, and failure mode were investigated.…”