On the mechanical properties and crack pattern analysis of a strain-hardening cement-based composite reinforced by natural sisal fibers

Abstract

Besides the strength enhancement and strain improvement (strain-hardening behavior), the use of natural fibers as reinforcement in cement-based matrices can also be highlighted as an economical and eco-friendly alternative for the future of the construction industry. In the present work, cement-based composites reinforced by natural sisal fibers were produced and tested under direct tensile loading. The Portland cement was partially replaced by pozzolans (metakaolin -MK and fly ash -FA), aiming to produce a calcium hydroxide-free matrix to ensure the durability of the fibers. The natural sisal fibers were used in a 5% volume fraction (in mass), divided into three layers. The mechanical properties of composite plates were compared to other literature results and demonstrated to be compatible with recent research. The crack pattern was analyzed by Digital Image Correlation (DIC) for a better understanding of their failure mechanisms. The material presented a tensile strength increase after the first crack formation, marked by multiple cracking partners from this point. Finally, a comparison between direct (LVDTs) and indirect (DIC) methods of strain measurement was done and demonstrated minor results for the DIC, approximately 84% of those obtained from the LVDTs.

Experimental investigation on soil stabilization technique by adding nano-aluminium oxide additive in clay soil

“…When this method is used, a lot of carbon dioxide is released. Aside from these problems, the cement stabilisation process is affected by the ratio of water to cement, the temperature at which the mixture cures, and the specific surface area of the mixture, the presence of contaminants or foreign substances and the presence of additives [1] Other than this traditional method, the following materials are used for chemical stabilization: GGBS, volcanic ash [11,12], fly ash, biomass bottom ash, Phosphogypsum, steel slag, concrete slurry waste [13], fibre and pith of coir, rubber waste, glass, polypropylene fibre, straw of barley fibre,sisalfibre [14], carpet waste, geogrid, geotextile, geocomposite, Chemical soil stabilisation involves modifying the physical-synthetic properties of clay particles so that less water is needed to maintain the static imbalance [15]. Apart from these materials recycled aggregate waste [16], plastics, red mud, kaolin waste etc are also nowadays used in civil works like concrete batch preparation and making building materials [17].…”