Analysis of innovative sandstone bricks and comparative performance evaluation with burnt-clay and fly-ash bricks

Abstract
This study presents an experimental evaluation of sawed sandstone units as an innovative masonry material and a comparative performance assessment against conventional burnt-clay and fly-ash bricks. Sandstone samples sourced from the Chakwal region were machined to standard brick dimensions and tested according to relevant ASTM procedures to determine physical properties such as apparent porosity, water absorption, initial rate of absorption, bulk density and specific gravity, as well as mechanical properties including modulus of rupture, unit compressive strength, masonry-prism compressive strength and bond shear strength. The sandstone units exhibited a mean unit compressive strength of approximately 33.3 MPa and a mean modulus of rupture of approximately 4.6 MPa. Water absorption was low, approximately 2 to 3%, and the initial rate of absorption was about 10.3 g per minute per 30 square inches, which favorably influences mortar performance and reduces moisture-related risks. Masonry prism tests indicated a practical wall-level compressive strength of approximately 10.1 MPa, whereas bond shear strength was relatively low at approximately 0.166 MPa, a result attributed to the smooth sawed surface of the stone. The findings indicate that with engineered surface treatments such as texturing or cavity formation and with optimized mortar formulations, sandstone bricks can serve as a sustainable, high-strength alternative to fired masonry in appropriate applications. By quantifying the performance and limitations of sandstone bricks, this work equips engineers, regulators and builders with the data needed to adopt lower-emission masonry options, update design guidance, and prioritize investments in sustainable construction practices.