Rheology helps to define the fresh concrete properties as required by specific applications and the concrete design can be
prepared as required. This research includes the study of rheological parameters of high-strength recycled concrete mixes of grade M50 and M60. The concrete mix is made by replacing certain percentages of natural coarse aggregates (NCA) with recycled coarse aggregates (RCA). Four concrete mixes were studied by varying proportions of RCA as 0%, 20%, 40%, and 60% each of grade M50 and grade M60. The empirical tests like the ‘slump cone test’ performed on concrete mixes to determine the workability mostly give only one-point results; often these tests are operator sensitive which is why a more quantitative estimate can be derived from fundamental physical quantities such as plastic viscosity and yield stress. The rheological parameters give more accurate and independent values which define workability according to the functions
where it is to be used. Various workability tests like the Slump Cone test, Flow Table test, Vee Bee test, and Compaction Factor test was carried on concrete mixes with the above-mentioned proportions of varying RCA and the results of tests are simulated to form equations of rheological parameters. The analysis and correlation of the four tests were done with the Multiple Linear Regression (MLR). The equations relating the yield stress and plastic viscosity of concrete with the empirical test were obtained for the literature and the graph obtained by these equations are plotted against the rheological parameters and the trendline showing its deviation is obtained. The percentage changes in the values obtained from the equations and the experimental results are also presented.