Pore, mechanics and acoustic emission characteristics of limestone under the influence of temperature

• Published in: Applied thermal engineering Vol. 123; pp. 1237 - 1244
• Main Authors: Zhang, Yuliang, Sun, Qiang, Cao, Liwen, Geng, Jishi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2017; Elsevier BV
• Subjects: Acoustic emission; Acoustic emission testing; Acoustic microscopy; Critical temperature; Curvature; Deceleration; Ejection; Emission analysis; High temperature; High temperature treatment; Limestone; Mathematical analysis; Pore; Porosity; Process parameters; Rocks; Scanning electron microscopy; SEM; Yield strength; Yield stress; Limestone; Acoustic emission; Yield strength; SEM; Pore; High temperature treatment
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2017.05.199

•340°C is a critical temperature at which several parameters change a lot in our research.•Great criteria for deformation and good precursor for destruction are found in acoustic emission information.•Explain the macroscopic properties based on the microstructure. The study on the properties of limestone after temperature treatment has a significant value for the engineering relating to high temperature. This paper reports the variations of pore distribution, porosity, wave velocity, yield strength and acoustic emission of limestone after different temperatures heating. The scanning electron microscope results are used to explain the microscopic mechanism of these parameters above. The injection process is divided into four phases (approximate straight-line increase phase, accelerated increase phase, decelerated increase phase, stagnant phase). After 340°C, the closed pores emerge which is the reason for mercury ejection. Uniformity coefficient and coefficient of curvature which were first proposed to describe pores reveal that the pore distribution becomes scattered versus temperature. Wave velocity and porosity have a good linear relationship. In acoustic emission information curves, there are obvious characteristics in stable fracture stage and unstable fracture stage. The ratio of yield strength to peak strength is between 0.7 and 1.0, with a slightly decrease after 340°C. Yield strength and wave velocity have a good linear relationship. 340°C is a critical temperature at which several parameters change a lot.