Susceptibility of Jhelum river bed aggregate to alkali silica reaction and its potential as construction aggregate.

Durability and suitability of concrete aggregates are influenced by mineralogical composition. This paper therefore discuses the mineralogical composition of Jhelum river aggregates and identifies the deleterious components responsible of ASR expansion, when used in normal weight concrete. Accelerated Mortar Bar Test (ASTM C-1260) and petrographic analysis were performed to determine the durability aspects of river aggregate. Aggregate Suitability was assessed by aggregate quality tests i.e. specific gravity & absorption, Loss Angeles abrasion, sulfate soundness, shape test, fineness modulus and sand equivalent. On obtaining satisfactory results of coarse aggregate tests, concrete mix designs for class-A, class-B, class-C and class-D were devised by absolute volume method (ACI- 211.1). Projected UCS (Unconfined Compressive Strength) considered 4000Psi for A-type, 3000Psi for B-type, 2000Psi for C-type and 1500Psi for D- type concrete at the at 28days. Results of 24 casted cylinders show that achieved average UCS at the age of 28 days is, 4921 Psi, 3773 Psi, 2780 Psi and 2432Psi for A, B, C and D-type concrete respectively. Jhelum River Aggregate is found mechanically fit and suitable for normal weight concrete. There are about 40% samples which deviate from the suitability standard of Accelerated Mortar Bar Test. Mineralogical studies of Jhelum river aggregate revealed that most of the aggregate components (Sandstone, Quartz Arenite) are suitable for construction but some of these are highly susceptible to alkali silica reaction due to the presence of highly strained quartz. The studied river aggregate is economical while used with slag cement and additives. [ABSTRACT FROM AUTHOR]