Behavior of Anchor Bolts in Concrete Masonry with Lightweight Grout

Lightweight (LW) aggregates (LWAs) improve fire resistance, moisture resistance, and durability in addition to reducing the self-weight of concrete. However, the ACI 318 code includes a modifi-cation factor (lambda) to account for reduced tensile capacity in LW concrete. LWAs are not currently permitted for use in masonry grout due to lack of test data to establish appropriate modifica-tion factors for the TMS 402/602 code. This study is a pilot study that aims to experimentally determine how the tensile breakout and shear breakout capacity of cast-in-place bent-bar anchors in masonry assemblies with LW grout compare with the predictions of TMS 402-16 for anchors in normalweight (NW) grout, and with results in the literature for assemblies using NW grout to see if addi-tional testing would be needed to determine a lambda factor for shear and tensile behavior of LW grout. The results indicate that a reduction factor for bent-bar anchor bolts in masonry constructed with LW grout may not be needed, but additional testing should be conducted with smaller bar diameters to demonstrate the consis-tency of these results across bar sizes.