Behaviour of Spread Footings Resting on Fibre-Reinforced Green Binder-Stabilised Sand Layers

The construction of spread footings supported on fibre-reinforced soil–cement layers is an option to avoid the excessive costs related to the building of deep foundations in low-bearing capacity soils. Besides, polypropylene fibres are frequently used in earthworks to minimise the drop in post-peak strength, leading to a more reliable solution reduction on the brittle response of the soil–foundation system. Thus, the present study assesses the load–displacement response of circular footings assented on polypropylene fibre-reinforced soil–cement layers bearing over a weakly bonded residual soil. Rather than the ordinary Portland cement, a sustainable binder composed of ground waste glass and carbide lime was used. Load tests were carried out on circular steel plates (diameter of 300 mm) resting on the fibre-reinforced soil–cement layers with distinct diameters (450 and 900 mm) and constant height of 300 mm. Likewise, load tests of steel circular plates (diameters of 300, 600, and 900 mm) bearing directed on the residual soil were conducted. The proposed solution has shown its usefulness in enhancing the bearing capacity of the foundation, and the inclusion of fibres was positive in augmenting the ductility of the response, inhibiting crack propagation throughout the cemented layer. Moreover, the coupling of existing analytical solutions proved to be a helpful way to predict the failure mechanism and the bearing capacity of sustainable treated layers bearing over low-bearing capacity soils, contributing to the comprehension of the conditions in which this kind of solution applies.