Self-Compacting Earth-Based Composites: Mixture Design and Multi-Performance Characterisation

Abstract

A new generation of self-compacting earth-based composites (SCEC) for vertical elements with fully exposed earth, in which the main feature is the elimination of compaction, is proposed in the current work. The first objective was to develop earth-based mixture compositions with locally available raw materials and achieve self-compactability. A Portuguese soil, typically employed in rammed earth construction, was stabilised using cementitious materials and a superplasticiser to ensure flowability. The mixture design studies allowed to achieve flowable fresh composites. Results on the hardened state showed that SCEC presents high compressive strengths (5–14 MPa). The electrical resistivity SCEC increased with time and achieved at least 5600 Ωm at 28 days, while mass loss stabilised after 14 days in a controlled environment room. Additional tests were performed on selected optimal SCEC mixtures: drying shrinkage and water capillary absorption, with promising results. Overall, this work provided initial boundaries for the mixture design and assessment of SCEC and opened the door for further studies on new and novel earth materials construction techniques.

Glass Bottle Earth Brick for Structural Wall

“…The objective is to create a self-compacting earth-based composite from local earth that will be utilised to construct a brick in which glass bottles will be cast. Several research efforts have been made to give earth-based materials similar properties to that of concrete, to enable casting and enhance their competitiveness in relation to other construction materials (Clausell et al 2021;Cong and Chen 2016;Gomaa et al 2022;Landrou et al 2016;Matos and Varum 2022;C. Ouellet-Plamondon and Habert 2014;C.…”

“…For this research, five different types of earth-based mortar mixtures with different compositions were created. The proportions of the mixtures are informed by a comprehensive review of existing literature, as documented by (Clausell et al 2021;Cong and Chen 2016;Gomaa et al 2022;Landrou et al 2016;Matos and Varum 2022;C. Ouellet-Plamondon and Habert 2014;C.…”

Learning from the Past: Parametric Analysis of Cob Walls

“…Guidance is provided in the form of parametric equations capable of computing collapse multipliers (for the limit analysis approach) or safety factors (for the linear elastic finite element method (FEM) approach). Such guidance could as well be used as a tool for the initial dimensioning, and later design, of new sustainable and resilient cob buildings, which is a field that has recently received increased attention [15][16][17][18][19].…”