Experimental Study on Strength and Deformation Characteristics of Rock–Concrete Composite Specimens Under Compressive Condition

Uniaxial and conventional triaxial tests were conducted on low-strength sandstone, concrete, and integral rock–concrete composite specimens by using TFD-2000 computer servo-controlled triaxial rock rheology testing machine, and the deformation and strength characteristics of rock–concrete composite specimens were studied. According to the test results, the uniaxial compression curves of the rock–concrete composite specimens can be divided into five distinct characteristic stages with peak stress up to 30.56 MPa, and brittle–ductile failure happens to the specimens. Under triaxial compression, the rock–concrete composite specimens have ductile dilatation failure (mainly compression), and the curves have obvious failure load, showing a linear change. In addition, the volumetric dilatation failure stress and yield stress of the rock–concrete composite specimens are basically the same, and the turning point of dilatation gets higher with the increasing confining pressure. Confining pressure can make the rock–concrete composite specimens more resistant to deformation and failure. The test results provide new ideas and basis for studying deformation and failure of rock–concrete composite and establishing constitutive equations.