Suitability of Gini moraines as natural pozzolanic material for Diamer Basha dam project

Abstract

Diamer Basha dam is to be located on the mighty Indus River about 315 km upstream of Tarbela dam. The dam will be 272 m high and constructed from roller-compacted concrete (RCC). Earlier studies for the RCC mixture and placement conditions regarding heat development showed that extensive use of cement substitutes is essential for the construction of the RCC dam. The total amount of cementitious substitutes will be up to 2·0 Mt, which need to be supplied over a period of 4·5–5 years. Potential substitutes (blast-furnace slag from Pakistan Steel Mills, Karachi and fly ash from Lakhra, Pakistan and Bathinda, India) were considered unfeasible due to low production capacities, long distances from the project site and political reasons. In this study, locally available potential pozzolanic materials from Gini Gah, about 54 km upstream of the dam site, were investigated through physical, chemical and pozzolanic activity tests to assess their suitability for use in mass concrete. The results revealed that glacial moraines obtained from Gini are acceptable for use in RCC.