Physical, mechanical and crystallographic properties of clay bricks and mortars of the sixteenth–nineteenth century monuments of East Punjab

The physical properties, mechanical properties and crystallographic composition of Nanakshahi clay brick and mortar of Eastern Punjab (India) historical monuments constructed during sixteenth to nineteenth century have been investigated. The historical monuments were visited and clay brick and mortar samples were collected and tested for physical, mechanical and crystallographic properties. The average size (cm) and weight of Nanakshahi clay bricks emerges to be 18.3 × 9.4 × 2.7 (L × B × H) and 1.28 kg respectively. The compressive strength of lime mortar, lime surkhi mortar and clay bricks vary from 1.72 to 1.88 MPa, 2.16 to 2.64 MPa and 21.64 to 161.8 MPa respectively. Elastic modulus of Nanakshahi clay bricks has been found to be in the range of 1.31–9.41 MPa. X-ray diffraction confirms that the mortar and clay brick samples of eastern Punjab have a crystalline molecular structure and are majorly comprised of quartz and calcium carbonate compounds, with minor proportions of hydrazinium hydrogen sulfide compound. The X-ray fluorescence analyses indicate that the lime surkhi mortar in historical monuments is lime-rich with lime binder to surkhi, sand aggregate proportion of 1:1.3:1.6.