FLEXURAL TENSILE-STRENGTH OF PARTIALLY GROUTED CONCRETE MASONRY

Partially grouted concrete masonry incorporates to some degree the beneficial properties of fully grouted concrete masonry at a reduced cost. It is also an economical and convenient means of improving the limited flexural tensile strength of hollow-concrete masonry and, hence, a study of flexural tensile strength of partially grouted concrete masonry was considered opportune. Methodology and techniques of one-third scale direct modeling were used in the study, for which the bond wrench test was used to determine the flexural tensile strength of wall assemblages. A total of 15 model walls were tested to determine the effect of grout spacing on flexural strength for bending normal to bed joints. Formulas were developed, empirically and analytically, for prediction of flexural tensile strength of partially grouted masonry. Test results indicate that flexural tensile strength improves significantly with reduced grout spacing, and that the apparent factor of safety of the ACI-530/ASCE-5 code of 1988 varies considerably for different extents of grouting.