Proportioning cement based composites with burnt coal cinder

This paper presents an experimental investigation to advance a stepwise procedure to proportion plain and slag concrete mixes with burnt coal cinder waste as coarse aggregate. When typical strength of coarse aggregate in concrete is lower than the concrete strength required, conventional methods such as British Method, ACI and country's standard code cannot be used directly since failure of concrete is predominantly by aggregate crushing. To analyze the data, concrete, for simplicity, is regarded as two phase composite of cement mortar matrix and coarse aggregate. With the concrete and constituent cement mortar matrix strengths and their respective volume fractions as input parameters, the typical strength of coarse aggregate in concrete is determined from linear law of mixtures. Using again the same law, the cement mortar matrix strength required for higher or at par to that of the typical aggregate strength is calculated. To arrive at water-cement ratio for matrix strength, the Generalized Abrams' law is employed.