Mechanical Behavior of Cemented Granular Aggregates under Uniaxial Compression

Abstract

Cemented granular aggregates composed of densely packed particles bound together by a matrix partially filling the interstitial pore space, connecting adjacent grains and forming cemented grain-to-grain contacts. The artificial cemented granular aggregates from the high alumina ceramics beads as particles and self-compacting cement paste as cement matrix are used to investigate the mechanical behavior under uniaxial compression testing. The samples are fabricated by using the technique of rock-filled concrete without disturbing the granular backbone. The results show that the elastic modulus of the cemented granular aggregates is nearly four times or even one order of magnitude higher than that of the cement matrix. It is found that a linear-elastic regime is a dominant behavior in the prepeak region, and strain-softening is accompanied by the strain-hardening after the peak strength. Both decreasing the matrix volume fraction and reducing the matrix strength make the strain-hardening behavior disappeared. Interestingly, the uniaxial compressive strength and elastic modulus are found to be a nonlinear function of the matrix volume fraction, whatever the strength of cement matrix. The strength increases rapidly with a relative small value of matrix volume fraction. The bulk effect of matrix on the compressive strength and elastic modulus becomes more significant beyond a critical threshold value.