Diagonal tensile strength and lap splice behavior of concrete masonry assemblies with lightweight grout

Lightweight (LW) grout is not yet permitted per the TMS 402/602-16 masonry design code as only limited testing has been done to characterize the difference in its behavior from normal weight (NW) grout. This paper presents an experimental investigation carried out as a part of a pilot project directed in comparing the performance of LW grout with NW grout by completing diagonal tensile strength tests and lap splice tests. For the diagonal tensile strength tests, three types of wall panels, each fully grouted with either expanded clay (EC) grout, expanded slate (ES) grout or NW grout, are constructed, and tested in accordance with ASTM E519. The results of the dataset are compared to the predicted diagonal tensile strength for a NW specimen using equations from TMS 402/602-16. For the lap splice test, two lap splice configurations are tested using masonry assemblies constructed with EC and ES grout. Regression analysis is used to compare this dataset to historical data of lap splice specimens with NW grout. For both the diagonal tension tests and the lap splice tests, results are compared to other NW masonry testing in the literature, if available. Additionally, parallels are drawn between the relative performance of masonry assemblies grouted with LW and NW grout and the relative performance of LW versus NW concrete specimens from the literature. The results of this study indicate that a reduction (2) factor in the design value of diagonal tensile strength and lap splice strength for masonry assemblies with LW grout is merited, analogous to reduction factors for these properties in LW concrete.