Compressed earth blocks stabilized with glass waste and fly ash activated with a recycled alkaline cleaning solution

Abstract

The study reported in this paper focused on the physical-mechanical properties of compacted earth blocks (CEB) stabilised with a sustainable alkali activated cement, completely produced from wastes and residues, including coal fly ash and glass waste (from the production of ophthalmic lenses) activated with an alkaline solution resulting from the aluminium industry. A common Portuguese silty clay was used as the mineral skeleton of the blocks, which were then evaluated based on the protocols of the UNE 41410 and DIN 18945-47 standards. The results evidenced the effectiveness of the alkaline cementing agent in forming a binding matrix for the soil particles, and the resulting material was used to manufacture the earth-based masonry elements. After a careful optimisation of the sustainable binder, an average compressive strength of 17.23 MPa, in unsaturated conditions, was obtained for the blocks. The newly formed soil-binder structure was very capable to withstand wetting and drying cycles, ice-thaw cycles and erosion. The microstructure of the material was further analysed, using scanning electron microscopy and energy dispersive spectroscopy. The results demonstrated the real possibility of using this type of cement as a viable alternative to traditional soil stabilisation binders used in earth construction.

Compressed Earth Blocks Using Sediments and Alkali-Activated Byproducts

“…The compressive strengths of few mixes were almost four times those needed to withstand higher loads. Furthermore, the obtained compressive strengths are more competitive with other previous studies, such as S. Larbi and J. Rivera with 6.64 MPa [32] and 12 MPa [5], respectively. However, the compression strengths of mixes with FA and GBFS are almost double those of FA mixes.…”

“…Moreover, the reuse of alternative materials has become a solution to reduce high levels of CO 2 emissions into the atmosphere, which represent considerable financial burdens and environmental challenges. Indeed, the construction industry consumes large amounts of raw materials (about 1 million tons/day) [4,5]. Therefore, the building sector is one of the areas where an action is imperative.…”

“…The sediments can potentially be used as alternative aggregates in the sector, especially in concrete, bricks etc. Dredged sediment can also be incorporated as sand in compressed earth blocks (CEB) [6], whose production consumes less energy than that of clay blocks [5].…”

“…The use of traditional binders such as Portland cement or lime for the manufacture of CEBs yield modest mechanical and physical properties (for example, compressive strength ranging between 2 and 4 MPa), including thermal. In addition, the use of cement and lime has an environmental impact because it generates significant greenhouse gas emissions [4,5]. The negative impacts of traditional block production (mechanical, physical, and economic) make finding alternative construction materials appropriate, even essential.…”

Study on Triaxial Mechanical Properties and Micro Mechanism of Fly Ash Reinforced Cement Calcareous Sand

“…The above studies show that Portland cement can play a better role in cementing calcareous sand and can effectively enhance the mechanical properties of calcareous sand. Industrial waste fly ash has been widely used as an admixture in cement-based materials such as concrete and cement-soil [17][18][19][20][21]. In addition to acting as a filler in cement-soil, it also participates in chemical reactions to generate products like that of cement hydration [22], which can effectively improve the strength of cement-soil.…”