Introducing a new aggregates index (AI) using petrograghical and geomechanical properties (Case study: Hamedan province limestones)

Aggregates are materials which are used extensively in construction industry such as concrete constructions¡ road base and subbase and rail ways. Hamedan province has extensive sources of limestones¡ so it is essential to evaluate the limestone characteristics for their applications in different civil projects. In this study¡ Hamedan limestones are classified based on their applications in projects with different sensetivites by considering aggregate parametrs (Aggregate impact value¡ Aggregate crushing value¡ Los Angeles aggregate abrasion value) and petrography investigations. This classification is called aggregate index (AI). Then¡ this index is divided to P wave velocity called aggregate adjusted index (AAI). Finally¡ this parameter has been estimated by simple and multiple (by using bestsubsets) regression methods¡ based on physical and mechanical properties of studied rocks. In simple regression¡ Schmit hammer rebound is the only parameter which has a determination coefficient less than 50% and it is not suitable for estimation¡ while in multiple regression the best parameters (e. g. P wave velocity¡ uniaxial compressive strength¡ tensile strength and dry density) have been chosen and unfavorable parameters have been ignored which finally leads to a relaible equation with 99% significant level.