Pozzolana
Historical use:
– Pozzolanas like Santorin earth used in Eastern Mediterranean since 500-400 BC
– Romans fully developed lime-pozzolan pastes for Roman concrete
– Vitruvius mentions four types of pozzolana: black, white, grey, and red
– Roman port at Cosa built of pozzolana-lime concrete under water
– Cosa’s three piers still visible in excellent condition after 2100+ years
Geochemistry and mineralogy:
– Volcanic pumices and ashes contain highly porous glass
– Alterable nature limits occurrence to active volcanic areas
– Chemical composition varies based on regional volcanism
– Mineralogical composition determined by presence of phenocrysts and parent magma
– Presence of associated minerals like feldspar, leucite, quartz, and pyroxenes
Modern use:
– Pozzolana extensively used in countries like Italy, Germany, Kenya, and China
– Used as addition to Portland cement
– Larger ranges in composition and physical properties compared to industrial by-products
– Expected to expand due to exhaustion of industrial sources and technical advantages
– Controlled by local availability and competition with industrial by-products
Pozzolanic reaction:
– Chemical reaction in Portland cement containing pozzolans
– Basis of Roman concrete invented in Ancient Rome
– Acid-base reaction between calcium hydroxide and silicic acid
– Studies on blended Portland cements containing Santorin earth
– Sustainable development and climate change initiatives related to pozzolanic reactions
References:
– Ludwig, U.; Schwiete H.E. (1963). Lime combination and new formations in the trass-lime reactions
– Mortureux, B.; Hornain H.; Gautier E.; Regourd M. Comparison of the reactivity of different pozzolans
– Mehta, P.K (1981). Studies on blended Portland cements containing Santorin earth
– Damtoft, J.S.; Lukasik J.; Herfort D.; Sorrentino D.; Gartner E.M. (2008). Sustainable development and climate change initiatives
– Cook D.J. (1986) Natural pozzolanas. In: Swamy R.N., Editor (1986) Cement Replacement Materialshttps://en.wikipedia.org/wiki/Pozzolana