Assistant professor, SJ College of Engineering, Mysore,
An integral part of concrete mix proportioning is the preparation of trial mixes and making adjustments to such trials striking a balance between the requirements of placement, strength, and durability. When coarse aggregate characteristic strength is lower than the levels of strength of the concrete desired, different methods, viz., British, ACI, and the country's standard code, cannot be used directly. In this paper a generalized method is advanced to proportion concrete using quarry wastes, namely, cuddapah and marble in concrete, as coarse aggregate. Concrete is regarded as a composite of cement mortar matrix and coarse aggregate. The basic principle of the method is to assess the characteristic strength of coarse aggregate from compressive strength data of concrete failed by aggregate fracture and from that characteristic strength to assess the cement mortar strength required so as to ensure the development of the required strength of concrete. To arrive at the exact water-cement ratio of mortar matrix, the generalized Abrams' law is used.
Paper ID: CCA10479J