Eocene Kohat Formation suitability as an aggregate from Kohat Range, Sub-Himalayas, Pakistan, based on outcrop, petrographic and geotechnical properties

characteristics of the Limestone of the Kohat Formation. The
Eocene Kohat limestone is generally exposed in the Kohat, Hangu,
and Bannu districts. Kohat Formation limestone is well exposed
throughout the Northern Kohat fold and thrust belt at Togh Bala
village. It is cream to grey, hard, compact, well-bedded and
fossiliferous. Kohat Formation has been identified into two
lithofacies which are from base to top calcareous shale lithofacies
with large benthic foraminifera and limestone lithofacies. The
faunal assemblage indicates that the Kohat Formation was deposited
in an inner to middle shelf environment. The petrographic analyses
of samples of the Kohat Formation depict that it principally consists
of calcite (60-90%) with a small to trace assemblage of dolomite (0-
3%), ungraded quartz (0-1.5%), opaque minerals (0-1.2%) and
fossils (8-40%). Aggregate physical properties like water absorption
(0.88%), specific gravity (2.69), soundness (2.55%), Los Angeles
abrasion value (23.06%), aggregate crushing value (11.56%),
aggregate impact value (12.68%), flaky index (9.90%), elongation
index (12.76%) and coating and stripping values (96.27%) conform
to available standards. Our results indicate that Kohat Limestone is
safe in terms of Alkali Carbonate Reactivity (ACR) and AlkaliSilica Reactivity (ASR). The facies, thin section study,
geochemical, and geotechnical understanding of Kohat Formation
indicate that these aggregate deposits are potential aggregate
sources for ballast (railway), road, building material, concrete,
mortar and other mega projects for connecting Asia and Europe.