Jagadeesh Bhattarai has completed his PhD in the Institute of Materials Research at Tohoku University, Japan in 1998. He has been working for more than thirty\r\nyears as a Faculty Member of Chemistry in Central Department of Chemistry at Tribhuvan University, Nepal and had promoted to Full Professor of Chemistry in 2013. He had carried out research works at Tokyo Institute of Technology from 1991-92 in the field of Clay Mineralogy and Tohoku Institute of Technology from 2007-08 in Japan. He has published more than 125 papers in reputed journals. Currently, he is the Chief Editorial Board Member of the Journal of Institute of Science & Technology an official journal of Institute of Science & Technology, Tribhuvan University, Nepal.

The mineralogical composition of the clay raw materials used for the production of different types of ceramic products like tiles, contemporary and ancient clay bricks is one of the main quality indicators of its physicomechanical properties. Hence, it is considered that the mineralogical phase analysis of the clay-based bricks is one\r\nof the important aspects of studies for the approximate estimation of physico-chemical and mechanical properties.\r\nIt is said that mechanical strength, i.e., durability of clay bricks depends on their physico-mineralogical properties.\r\nThe mineralogical, physical and mechanical properties of the fired clay bricks are generally inter-related to each\r\nothers. Considering these facts, present work was focused to investigate the properties of mineralogical composition,\r\nwater absorbtivity (WA), apparent porosity (AP), bulk density (BD) and compressive strength (CS) of twenty four different types of contemporary (17 samples) and ancient (7 samples) bricks of Katmandu valley using XRD, FTIR\r\ntechniques and ASTM standards. Minerals in the analyzed brick samples were found mainly of quartz, feldspars, spinel with primary mullite, muscovite, margarite and hematite. Disappearance of feldspars and appearance of the\r\nalumina-rich spinel and primary mullite phase peaks in all brick samples are not same degree indicating that the firing temperature used to produce these brick samples should not be same. It is a good correlation between the physical properties of WA, AP and BD with CS for both types of ancient and contemporary brick samples. In general, compressive strength of all analyzed samples is found to be increased with decreasing the WA and AP, and with increasing the BD as depicted in Figs 1(a) and 1(b). Furthermore, the durability of ancient bricks seems to be more than contemporary ones.