Experimental Study on Mechanical Properties of Low-Strength Mortar–Granite Composite Specimens.

To study the quasi-static compressive mechanical properties of low-strength mortar–granite composite specimens, quasi-static compression experiments were carried out on composite specimens with different contact angles and mortar strengths and specimens of pure mortar. The failure, stress state, and structural characteristics of the specimen were analyzed. The strength differences and failure modes of the pure mortar specimens and composite specimens were obtained. The strength of the composite specimens is slightly greater than that of the corresponding pure mortar specimens. When the strength of the mortar reaches 50 MPa, the failure mode of the composite specimen changes from only crushing to both crushing to sliding. The strength of the mortar is the main factor influencing the strength and failure mode of the composite specimens. Highlights: The failure mode of composite samples comprising low-strength mortar and high-strength granite was investigated. The damage to the composite samples mainly occurred in the mortar parts. Moreover, the strength of the composite samples was slightly greater than that of the pure mortar samples of the same size. The effects of the contact angle and mortar strength on the uniaxial compressive strength and failure characteristics of the composite samples were studied for the first time. Notably, the contact angle and mortar strength jointly affected the failure form of mortar. Under a low mortar strength, with increasing contact angle, the composite samples experienced two failure modes: crushing and sliding. Under a high mortar strength, the influence of the contact angle on the failure form of the composite samples decreased, and the samples were destroyed as a whole. The main factor influencing the strength of the composite samples was the strength of the mortar. A distribution model for the internal stress in the composite samples was established. By analyzing the internal stress distributions in the composite samples with different contact angles, the fragile zones and failure modes were obtained. [ABSTRACT FROM AUTHOR]