Mixed-mode I + II tensile fracture analysis of thermally treated granite using straight-through notch Brazilian disc specimens

Effect of microwave heating on fracture behavior of granite: An experimental investigation

This paper presents the results of an experimental investigation on the deformation and cracking behaviors of ring-shaped granite specimens. Diametrical compression tests were conducted on ring-shaped granite specimens with inclusion and those without inclusion for comparison. The inclusion materials were of different strengths, stiffness, and sizes. Strain gauges (SGs) were amounted at the boundary of the hole to trace the strain evolutions, and digital image correlation (DIC) technique was used to identify the crack initiation and propagation process. The results indicated that the inclusion has a positive effect on the enhancement of the carrying capacity. The maximum carrying capacity of the specimen with low-strength inclusion decreases with increasing the inclusion diameter, while it first decreases and then increases when the inclusion diameter increases from 10 to 20 mm for the high-strength infilled specimens. The results of the strain evolutions analyzed by the SGs and DIC methods indicate that a lager hole diameter and a lower inclusion strength lead to a more intensive strain concentration around the hole. Due to the mismatch in the deformation at the rock–cement mortar interface, serious strain concentrations are induced, and hence leading to three types of failure, i.e., debonding between the interface, tensile crack in the granite, and tensile crack in the inclusion material.

Deformation and cracking characteristics of ring-shaped granite with inclusion under diametrical compression

Experimental study on wave propagation through granite after high-temperature treatment

Loading rate effect on mixed mode I/II brittle fracture behavior of PMMA using inclined cracked SBB specimen

Determination of double-K fracture toughness parameters of thermally treated granite using notched semi-circular bending specimen

Determination of the mixed mode I/II fracture characteristics of heat-treated granite specimens based on the extended finite element method

Experimental investigation on dynamic mechanical behavior and fracture evolution of fissure-filled red sandstone after thermal treatment

The stability of rock mass after fire is a concern of many engineering projects. In this paper, the effects of open fire and different cooling methods on granites were investigated. The static Brazilian test, dynamic Brazilian test, and P-wave velocity test were carried out to evaluate the mechanical properties and damage evolution behavior. A high-speed camera is employed to monitor the failure process of rock. The microstructures of the treated granites were observed by scanning electron microscope (SEM). The results showed that the fire duration and cooling treatment have a significant effect on the P-wave velocity, static nominal tensile strength, and dynamic nominal tensile strength of granite. These characteristics decrease rapidly during 0 to 10 min, and slowly decrease after 20 min. Compared to the air-cooling treatment, the water-cooling treatment has greater damage to the heated granite. To better understand the results, the rapid heating process of open fire heating was simulated using Abaqus software. The results reveal that there is a thinner compressive stress zone at the bottom of the specimen, and there is a large zone in the middle of the sample with higher tensile stress. The crack extension would be expanded due to high tensile stress, leading to the reduction of the tensile strength of the rock. This paper aims to better predict the degree of damage of rock materials after actual fire, as well as preliminarily explore the effect of the fire exposure duration and fire extinguishing method on the tensile properties of rock.

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Papers

Determination of double-K fracture toughness parameters of thermally treated granite using notched semi-circular bending specimen

Mixed-mode I + II tensile fracture analysis of thermally treated granite using straight-through notch Brazilian disc specimens

Determination of the mixed mode I/II fracture characteristics of heat-treated granite specimens based on the extended finite element method

Experimental investigation on dynamic mechanical behavior and fracture evolution of fissure-filled red sandstone after thermal treatment

Experimental investigation on the effect of open fire on the tensile properties and damage evolution behavior of granite