Print Email Facebook Twitter What Makes Cow-Dung Stabilised Earthen Block Water-Resistant? Title What Makes Cow-Dung Stabilised Earthen Block Water-Resistant? Author Kulshreshtha, Y. (TU Delft Materials and Environment) Vardon, P.J. (TU Delft Geo-engineering) Meesters, G.M.H. (TU Delft ChemE/Product and Process Engineering) van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology) Mota, Nelson (TU Delft Space & Type) Jonkers, H.M. (TU Delft Materials and Environment) Date 2022 Abstract The water-resistance of cow-dung has made it a widely used stabiliser in traditional earthen structures in several Asian and African countries. Multiple studies have shown an improvement in water-resistance with the addition of cow-dung, but none provides insight into this behaviour. The present study investigates the water-resistance behaviour of cow-dung stabilised earthen blocks through an extensive experimental programme to identify and characterise the components of cow-dung responsible for its water-resistance. Fresh cow-dung was collected and separated into fibres (>63 μm), medium-sized microbial aggregates (1-63 μm) and small-sized microbial aggregates (0.5-7 μm). Each component was mixed with soil and samples were prepared at different water contents (optimum water content corresponding to the highest dry density and water content higher than optimum) and compacted with 2.5 MPa force to prepare compressed blocks. The water-resistance of these blocks was evaluated through the immersion and modified drip/rain test. It was found that the small-sized microbial aggregates are almost entirely responsible for water-resistance behaviour of cow-dung stabilised earthen blocks. Small-sized microbial aggregates were further characterised by gas chromatography, mercury intrusion porosimetry, N2- BET surface area, zeta potential measurement and electron microscopy. The results indicate that the small-sized microbial aggregates are composed of clay-sized negatively charged particles that are rich in fatty acids. The hydrophobicity of these particles is hypothesised to be responsible for water-resistance behaviour. These insights are further used to produce stabilised blocks that performed at least 30 times better than the unstabilised blocks in both water-resistance tests. The study concludes with practical recommendations for the use of wet cow-dung over dry cow-dung and a reduction of fibre content to increase the water-resistance of earthen blocks. Subject Cow-dungearthen constructionwater-resistanceimmersionmicrobial aggregates To reference this document use: http://resolver.tudelft.nl/uuid:77bc5836-8f61-4004-95ad-c4bf9ca2a5e2 DOI https://doi.org/10.4028/www.scientific.net/CTA.1.540 ISSN 2674-1237 Source Construction Technologies and Architecture, 1, 540-548 Part of collection Institutional Repository Document type journal article Rights © 2022 Y. Kulshreshtha, P.J. Vardon, G.M.H. Meesters, Mark C.M. van Loosdrecht, Nelson Mota, H.M. Jonkers Files PDF CTA.1.540.pdf 1.21 MB Close viewer /islandora/object/uuid:77bc5836-8f61-4004-95ad-c4bf9ca2a5e2/datastream/OBJ/view