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

Abstract

Rice husk is an agricultural by-product worldwide in large quantities available. This is a suitable biomass source for energy production. Compared to other agricultural by-products, the burned rice husk presents a high yield of ash (about 20%) mainly composed of silica that will be mostly amorphous when properly incinerated. Extensive research in the past three decades has allowed the introduction of rice husk ash (RHA) as a supplementary raw material in cement-based products, whereby significant improvements in strength and durability can be achieved, also contributing to ecological demands. This paper investigates the influences of two RHA admixtures on the physical and mechanical properties of bamboo-pulp-reinforced cement composites. These fibers suffer early degradation in the alkaline environment. RHA blending will reduce the ordinary Portland cement (OPC) content and can improve strength and density due to more effective particle packing, and significantly diminish alkalinity. The composites were produced in the laboratory by a method resembling the Hatschek process used by the fibrocement industry, with fixed reinforcement content and varying amounts of RHA. The results revealed that partial replacement of ordinary Portland cement by up to 30% of RHA had not impaired the mechanical behavior of the composites. Further, use of low-carbon-content RHA decreased porosity in the matrix and enhanced interfacial bonding of the composites. Since the deterioration of cellulose-cement composites is closely related to moisture movement and alkalinity, it is concluded that introduction of low-carbon content RHA can lead to improved durability performance of these composites.

Use of Rice Husk Ash as Partial Replacement of Cement in Sandcrete Blocks

“…X-ray fluorescence analysis was used for determination of chemical composition. The silica content in the RHA was 73% that was in agreement with the previous published research and indicated high possible reactivity of RHA as pozzolanic/ cementing agent [16,17].…”

Evaluation of the mechanical properties and durability of cement mortars containing nanosilica and rice husk ash under chloride ion penetration

“…Sufficient grinding of RHA allows the dissolution of silica in the highly alkaline environment of the cement paste and the reaction of SiO 2 , Al 2 O 3 and Fe 2 O 3 existing in RHA with Ca(OH) 2 , produces C-S-H (calcium silicate hydrate), C-A-H (calcium aluminate hydrate) and C-A-F-H (calcium aluminate ferrite hydrate) that results in a higher densification of the matrix [38,39]. Also, the finest RHA particles tend to concentrate near the aggregate-matrix interface, leading to reduced porosity and enhanced internal bonding capacity [40].…”

Comparison and Evaluation of Co-composting Corn Stalk or Rice Husk with Swine Waste in China

“…A few of researchers proposed improved methods, for instance, Zhang et al [49] and Soda et al [50] found that rice husk ash had an obvious effect on co-composting with livestock manure and remediation of acidic polluted soil. Isoda et al [51] prepared activated carbon from rice husk, Conrado et al [52] introduced rice husk ash as a supplementary raw material in cement-based products. These study works provided a new approach for rice husk utilisation as a resource in China.…”