Effect of fibre type and content on performance of bio-based concrete containing heat-treated apricot shell

Abstract

The heat-treated apricot shell can be utilized as coarse aggregates for producing sustainable bio-based lightweight concrete with good compressive strength but poor tensile strength. In order to improve the tensile properties of apricot shell concrete (ASC), the effects of polypropylene (PP) fibre, glass (G) fibre and basalt (B) fibre at various volume fractions (Vf) (0.25%, 0.5% and 0.75%) on the performance of ASC were investigated. The results indicated that the fibre type had no significant effect on the physical properties of ASC such as slump, density, water absorption and permeable porosity. However, the slump of ASC decreases with an increase in fibre content. The B fibre has a better improvement in mechanical properties than the PP fibre and G fibre thanks to the better elastic modulus and tensile strength. When the Vf was 0.5%, the compressive strength, splitting tensile strength, flexural strength and modulus of elasticity of ASC reinforced with B fibre were increased by 16.7%, 29.1%, 29.2%, and 18.1%, respectively, compared to ASC without any fibres. The magnesium sulfate attack results showed that the incorporation of the B fibre decreased the mass loss and compressive strength of ASC exposed to a MgSO4 solution for 6 months because the fibre arrested the microcracks caused by the expansive stress. It is concluded that the mechanical properties of bio-based ASC and its resistance to magnesium sulfate attack can be significantly improved by incorporating 0.5% B fibre.

Impact of Addition of Banana Fibres at Varying Fibre Length and Content on Mechanical and Microstructural Properties of Concrete

“…Also, incorporation of banana fibres in concrete alters its failure mode from a brittle to plastic failure and hence mitigating the formation and propagation of cracks. Similar results were observed by other researchers who reported that fibres control microcrack formation and lead to the delay in failure and hence increasing the ultimate strength and strongly contribute in the load carrying capacity of the postpeak phase [58][59][60]. It has also been suggested that incorporating fibres in concrete enables it to resist extra compressive stress by blocking and redirecting the cracks [61].…”

“…A similar behavior of an initial increase in tensile strength up to a certain amount of fibre content and thereafter experiencing a drop with further increase in fibre content has been observed in another study [58]. Wu et al [58] observed that for all fibres used (i.e. polypropylene, glass, and basalt fibres), splitting tensile strength of apricot shell concrete (ASC) significantly increased when the fibre content was increased from 0.25 to 0.50% but then dropped when the fibre content was increased from 0.5 to 0.75%.…”

“…Also, as already discussed, incorporation of banana fibres in concrete alters its failure mode from a brittle to plastic failure especially as the fibre content increases because fibres adequately inhibit the formation and propagation of cracks as well as limiting the confluence of cracks and adsorbing more destructive energy in the end [59]. Similar results were observed by other researchers who reported that addition of fibres had a significant improvement in tensile strength because they slowed down crack propagation, thereby enhancing mechanical strength of concrete [16,58,65,66]. A drop in tensile strength of BFRC beyond 1% of fibre content can be attributed to excessive amount of fibre content in the concrete, which end up having an adverse effect on the strength of concrete as was similarly observed for compressive strength.…”

“…However, it was observed that beyond 1% of fibre content, all BFRC mixes exhibited a drop in strength values with increasing fibre content. A similar behavior of an initial increase in tensile strength up to a certain amount of fibre content and thereafter experiencing a drop with further increase in fibre content has been observed in another study [58]. Wu et al [58] observed that for all fibres used (i.e.…”

Durability Performance of Basalt Fiber-Reinforced Concrete Subjected to Sulfate–Magnesium Combined Attack

“…With excellent toughness, BF inhibits the formation of micro-cracks in the concrete and improves its compactness [ 34 ]. Many studies indicate that the use of BF enhances concrete’s resistance to sulfate attack [ 33 , 35 , 36 , 37 , 38 , 39 ]. Wang et al [ 38 ] found that an appropriate amount of BF can limit the expansion of pores and cracks, thereby enhancing corrosion resistance, but excessive BF would adversely affect durability.…”