Browsing by Author "Premarathne K.D.H.J."

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Open Access
Geochemical insights into ancient burnt clay bricks in Sri Lankan archaeological structures
(Elsevier B.V., 2026-07) Premarathne K.D.H.J.; Young, Sansfica M.; Mendis T.; Rajapaksha M; Jayasekara J.M.I.R.K.; Halwatura R.U; Kamei A.
Ancient burnt clay bricks in Sri Lanka exhibit comparatively advanced technological characteristics relative to many contemporary clay bricks (1–5 MPa), suggesting the presence of optimized material design principles. This study investigates the geochemical signatures and structure–property relationships of ancient clay bricks with relatively high compressive strengths to derive insights relevant to the development of sustainable modern construction materials. Ancient burnt clay bricks were collected from ten stupas located in Anuradhapura, Sri Lanka. Standard methods were used to test the compressive strength of the brick samples. Advanced materials characterization techniques, including X-ray fluorescence (XRF), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were employed to analyze the geochemical signatures. The data were analyzed to explore provenance trends, relative weathering alteration, chemical composition, mineralogical phases, and possible firing temperature ranges of the ancient burnt clay bricks. The provenance analysis is broadly consistent with relatively felsic source materials of dacitic to rhyolitic affinity. A significant correlation was identified between flux content (19.56%) and compressive strength (9.78 MPa), suggesting that vitrification and densification may have contributed to improved mechanical performance. Further, the bricks are consistent with production from non-calcareous, low-refractory clays (CaO < 6%), with flux levels exceeding 9%, which may have supported effective sintering during firing. The higher-strength burnt clay bricks likely experienced comparatively higher firing temperatures, as indicated by the possible presence of high-temperature mineral phases such as mullite and diopside. SEM-EDX results suggest that the morphology and elemental distribution patterns of the clay bricks may have contributed to higher compressive strength. Overall, the findings suggest that ancient brick production involved favorable material characteristics and firing conditions, providing a useful basis for the development of next-generation sustainable clay-based construction materials.