Environmentally Friendly Utilization of Wheat Straw Ash in Cement-Based Composites

Abstract

The open burning of biomass residue constitutes a major portion of biomass burning and leads to air pollution, smog, and health hazards. Various alternatives have been suggested for open burning of crop residue; however, each of them has few inherent drawbacks. This research suggests an alternative method to dispose wheat straw, i.e., to calcine it in a controlled environment and use the resulting ash as a replacement of cement by some percentage in cement-based composites. When wheat straw, an agricultural product, is burned, it is very rich in SiO 2 , which has a pozzolanic character. However, the pozzolanic character is sensitive to calcination temperature and grinding conditions. According to the authors' best knowledge, until now, no systematic study has been devised to assess the most favorable conditions of burning and grinding for pozzolanic activity of wheat straw ash (WSA). Hence, a systematic experimental program was designed. In Phase I, calcination of WS was carried out at 500 • C, 600 • C, 700 • C, and 800 • C for 2 h. The resulting ashes were tested for color change, weight loss, XRD, XRF, Chapelle activity, Fratini, and pozzolanic activity index (PAI) tests. From test results, it was found that beyond 600 • C, the amorphous silica transformed into crystalline silica. The WSA calcined at 600 • C was found to satisfy Chapelle and Fratini tests requirements, as well as the PAI requirement of ASTM at 28 days. Therefore, WSA produced at 600 • C (WSA600) showed the best pozzolanic performance. In Phase II, WSA600 was ground for various intervals (15-240 min). These ground ashes were tested for SEM, Blaine fineness, Chapelle activity, Fratini, and PAI tests. From test results, it was observed that after 120 min of grinding, there was an increase of 48% in Blaine surface area, with a consequence that WSA-replaced cement cubes achieved a compressive strength almost similar to that of the control mix. Conclusively, wheat straw calcined at 600 • C and ground for 120 min was found to be the most effective way to use pozzolanic material in cement-based composites. The addition of WSA in cement-based composites would achieve manifold objectives, i.e., aiding in the production of environmentally friendly concrete, the use of wheat straw as fuel for electricity production, and adding economic value to wheat straw.

Evaluating the Effect of Calcination and Grinding of Corn Stalk Ash on Pozzolanic Potential for Sustainable Cement‐Based Materials

“…When ashes obtained from agricultural by-products are used in cement-based materials, they resolve the matters of sustainability as well as create more durable concrete by acting as pozzolans [17,18]. Research studies that have been conducted on bagasse ash and RHA have shown significantly viable results.…”

An Approach to a New Supplementary Cementing Material: Arundo donax Straw Ash

“…Rice straw ash (RSA) has been characterized and used to replace 10% and 25% OPC [11]. Wheat straw ash and corncob ash were studied by Memon et al [12,13] and demonstrated good pozzolanic performance of the ash, aiding in the production of environmentally friendly concrete. Elephant grass ash (EGA) has been studied in terms of pozzolanic reactivity and the development of eco-friendly cements [14][15][16].…”

Incorporation of Wheat Straw Ash as Partial Sand Replacement for Production of Eco-Friendly Concrete

“…In short, researchers found the incorporation of agricultural and industrial waste suitable for the achievement of sustainable concrete as it has disposal problems and depletion of natural sand associated with it. It is worth mentioning that WSA has been previously used as a cement blend and composite [ 38 , 39 , 40 ]. The high concentration of amorphous silica in WSA induces pozzolanic reaction upon its incorporation in concrete [ 40 ], like that of other supplementary cementitious materials such as fly ash, ground granulated blast furnace slag and metakaolin as reported in the literature [ 41 ].…”