Development of vegetable fibre–mortar composites of improved durability

Abstract

The primary concern for vegetable fibre reinforced mortar composites (VFRMC) is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength and toughness as a result of weakening of the fibres by a combination of alkali attack and mineralisation through the migration of hydration products to lumens and spaces. This paper presents several approaches used to improve the durability performance of VFRMCs incorporating sisal and coconut fibres. These include carbonation of the matrix in a CO 2 -rich environment; the immersion of fibres in slurried silica fume prior to incorporation in the ordinary Portland cement (OPC) matrix; partial replacement of OPC matrix by undensified silica fume or blast-furnace slag and a combination of fibre immersion in slurried silica fume and cement replacement. The durability of the modified VFRMC was studied by determining the effects of ageing in water, exposure to cycles of wetting and drying and open air weathering on the microstructures and flexural behaviour of the composites. Immersion of natural fibres in a silica fume slurry before their addition to cement-based composites was found to be an effective means of reducing embrittlement of the composite in the environments studied. Early cure of composites in a CO2-rich environment and the partial replacement of OPC by undensified silica fume were also efficient approaches in obtaining a composite of improved durability. The use of slag as a partial cement replacement had no effect on reducing the embrittlement of the composite.

Rice Husk Ash as a Supplementary Raw Material for the Production of Cellulose–Cement Composites with Improved Performance

“…These mechanisms are described in detail in the literature [14,15] and specifically concern the composite's strength loss due to:…”

“…Durable cellulose-cement composites can be obtained at low matrix alkalinity and reduced porosity and permeability of the matrix and interfaces [14,15]. The incorporation of mineral admixtures in cement-based materials results in chemical and physical effects of interrelated nature.…”

Natural fiber nonwoven reinforced cement composites as sustainable materials for building envelopes

“…The use of cellulosic or vegetable fibers has emerged during the last decades as an interesting option to substitute for asbestos, allowing the development of materials with good performance at relatively low cost [6][7][8][9]. Cellulosic fibers provide adequate stiffness, strength, and bonding capacity to cement-based matrices, enhancing their flexural strength, toughness, and crack resistance.…”

Comparison of thermal behavior of natural and hot-washed sisal fibers based on their main components: Cellulose, xylan and lignin. TG-FTIR analysis of volatile products

“…Furthermore, their biomass component proportion makes them suitable for processability and biofuel production [15,16]. In particular, Agave sisalana fiber or sisal fiber is one of the most widely used due to its good mechanical properties, used in a great variety of traditional applications due to its hardness, coarseness and resistance to wear, which has gained great interest during the last decades in the manufacturing of composite materials, particularly as reinforcement of mortars, concrete and polymeric matrices [17][18][19], as polypropylene [20][21][22].…”