Abstract
Grouted concrete block masonry (GCBM) exhibits distinct directional properties. In total, 66 tests on 5 kinds of macro-elements were conducted for different principal stress ratios under biaxial compression. The surface of peak strength has been obtained in terms of heterogeneity index and stress ratio. The surface can express the anisotropic nature of GCMB. Comparisons of 5 kinds of macro-element failure curves were made and it has been found that the biaxial compressive strength when the applied stress direction and the material axis coincide is much greater than that of applied stress inclined to material axis. On term of heterogeneity index and stress ratio, the law of strength varying with orientation has been obtained. It shows that the degree of anisotropy is affected by the stress state. Strong behaviour occurs only when one principal stress predominates, that is, the stress ratio value is low, and gradually becomes weaken as the difference between the two principal compression stresses decreases, namely the stress ratio is increasing. Under equal biaxial compression, the different macro-element strengths are nearly equivalent and the masonry seems to be isotropic. The work conducted in this paper provides a basis for further theoretical study on the behaviour of GCBM under biaxial compressive stress.