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This research investigated the development of a fast-drying silica-based binder for hemp concrete products with enhanced mechanical and thermal properties. Hemp-silica bio-composites were prepared by mixing hemp shivs with a two-component binder system composed of liquid sodium silicate and tributyl citrate (TBC). Compressive strength, thermal conductivity, moisture buffering value, cyclic moisture resistance and microstructure of hemp-silica composites were analysed, and the results were compared with those of hemp-lime concrete. Hemp-silica blocks with shiv-liquid sodium silicate mass ratio of 1:3.75 and TBC content of 37.5 wt% of sodium silicate dry matter produced a compressive strength of 0.56 MPa only after 3 days of drying and 1.92 MPa after 28 days. These were higher than hemp-lime blocks at the same density range. Hemp-silica panels showed a thermal conductivity of 0.101 W/mK and an excellent moisture buffering value of 3.49. Hemp silica formed an open porosity with large air gaps between the particles and a water-resistance silica-based layer on the shiv surface producing a higher moisture resistance compared to hemp-lime systems. This paper focuses on the development of a novel fast-drying binder system with a potential for use in conjunction with other lingnocellular plant aggregates to form low-carbon and efficient multifunctional building materials. • A novel quick-drying silica-based binder for hempcrete was developed. • Hemp-silica concrete showed enhanced mechanical properties compared to hemp-lime. • Hemp-silica concrete reached 0.56 MPa only after 3 days of drying. • Tributyl citrate improved the water resistance of sodium silicate binder. [ABSTRACT FROM AUTHOR]

Clay is used as a raw material for the production of lightweight aggregates because it is readily processed into suitable granules and forms low-density but high strength aggregate particles when sintered at relatively low temperatures. The use of waste clay generated by major infrastructure development projects to make lightweight aggregate has a positive environmental impact and contributes towards a more circular economy. This paper reviews the manufacturing process used to produce lightweight aggregates from clay and the influence of processing conditions on properties. It also reviews secondary materials that have been incorporated into clays to produce lightweight aggregates. Additional research is required to improve understanding of the effects of composition and production parameters on the pore structure, density, water adsorption and strength of clay derived lightweight aggregates. [ABSTRACT FROM AUTHOR]