BIOCHAR AND ITS EFFECTS ON INTERLAYER BOND STRENGTH IN 3D-PRINTED CONCRETE STRUCTURES

Abstract

Additive manufacturing within the built environment has been gaining traction as it brings about economic and environmental benefits that can potentially change how construction is carried out in the future. On the other hand, biochar, a versatile eco-material produced from pyrolyzing biomass, possesses several benefits and has also been used within the industry as an additive to enhance the properties of building materials. While 3D concrete printing is a promising mechanism to address many issues of traditional construction, it comes with limitations of its own, such as the reduction of bond strength with increased placement time between two 3D-printed concrete layers. This study integrates biochar to address this limitation of 3D printing, by hypothesising that the material’s excellent water retention properties can reduce surface evaporationbefore the next layer is printed, by placing a water-saturated biochar netting in between the printed layers. Samples were prepared and tested via a series of mechanical tests to validate this hypothesis. The resulting data shows the hypothesis is invalidated, as the biochar netting at the interface of the concrete actually served as a barrier limiting the amount of space available for the concrete layers to bond with each other. Hence, the interlayer bond strength of the samples were reduced significantly compared to the control. However, it was also discovered that the biochar netting improved ductility, giving the samples more residual resistance. It may even enhance material strength based on the findings of the bending test; however, further research is necessary to look into these claims.