Analytical deflection modelling of symmetric non-prismatic reinforced laterite-concrete slabs

This study investigates the intricate interplay between geometric attributes and mechanical characteristics of non-prismatic concrete slabs. Analytical models were derived which showed the extent to which the geometry, as well as the mechanical properties of non-conventional constituent materials, influence the flexural response of non-prismatic slabs. This study adapted the Euler-Bernoulli beam theory as well as the theory of plates and shells to derive a time-dependent model. The derived time-deflection response includes a Weierstrass function which was resolved through the assumptions of appropriate boundary conditions. Experiments were also carried out to obtain basic mechanical properties of reinforced laterite-concrete prismatic beams which were used as input parameters in the analytical model for the non-prismatic slabs. The singly reinforced concrete slab model investigated showed a non-linear relationship between the anchorage bond and the shear adequacy due to the addition of laterite, thereby increasing the shear capacity of the slab by over 70 % at a replacement of total aggregate volume by 22 % of laterite. The optimization of aggregate proportion was obtained using a pseudo-inverse model, with coefficients of determination of 99.91 % and 99.95 % for the respective grades of concrete, hence indicating the robustness of the findings. This study is expected to contribute to the development of more precise analytical models for designing and optimizing non-prismatic concrete slabs. • Modelling of behaviour of symmetric non-prismatic laterite-concrete slabs was carried out. • Fundamental theory of beam, plate and shell were used to derive the models. • Analytical models were validated with experimental data. • Optimum aggregate proportions were obtained using a pseudo-inverse model. • Enhanced shear resistance indicates the benefit of laterite inclusion in concrete.