Thermal and flexural properties of bagasse/cement composites

Abstract

Enhancing the sustainability, circular economy and use of by-products and renewable resources concerns a great number of researchers. Adding value to tropical vegetable resources and proposing a replacement for asbestos are challenges for chemists. Sugar cane bagasse is evaluated both as a mineral replacement and as a reinforcement in cementitious paste. In this matrix, ordinary Portland cement is partly replaced by natural pozzolan and bagasse ashes; a ternary binder is obtained. The pastes reinforced with vegetable fibers are prepared by the incorporation of untreated and pyrolyzed bagasse fibers (2-6 wt%) in this modified matrix. The thermal conductivity and the bending strength of the composite pastes, placed in various environments (curing chamber and water), are evaluated and compared to those of composite pastes made with commercial cement and bagasse fibers, exposed to identical aging conditions. The more relevant results are obtained in the curing chamber: the composite pastes prepared with the ternary matrix conduct less heat than the commercial binder composites at 28 d, and better bending strengths are obtained with the ternary binder composites at 28 and 90 d, particularly with the untreated bagasse fibers. . IntroductionGuadeloupe is a French Caribbean island with a tropical climate (latitude 16°59¢45″ north, longitude 62°04¢03″ west) and where seismicity is high and hurricanes occur frequently, so the choice of construction materials takes an essential place in structure design. As the durability of construction materials is strongly related to the exposure conditions, metallic structure degradation by corrosion is one of the preoccupations of researchers.As shown by various authors, 1-3 a way to prevent structure corrosion is the use of pozzolanic materials during the preparation of pastes, mortars or concretes. These silico-aluminous materials, when they are finely crushed, 4 react with the calcium hydroxide (Ca(OH) 2 ) released during cement hydration, to form products of the same chemical nature as the hydration products of cement. In Guadeloupe, cement is widely used for construction. A way to prevent the corrosion of steel framework in concrete is the partial replacement of cement by natural local pozzolan or ashes prepared from agro-industrial by-products. As indicated by Malhotra and Metha, 5 using pozzolanic materials coming from vegetable, mineral or agro-industrial by-products leads to (a) mechanical and physical-chemical benefits: improved mechanical strength, low permeability and strength against aggressive chemicals and thermal cracking; (b) economic benefits: reduced cost of buildings with the replacement of 20-60% by mass of cement by pozzolanic materials; and (c) ecological benefits: reduction of greenhouse gas (GHG) emission because of the partial replacement of cement in concrete and contribution to sustainability.Moreover, French thermal and acoustic regulations 6 expect autosufficiency and use of 50% renewable power in energy consumption by 2020. These regulations are essentia...

Editorial: Non-conventional materials

“…In the fourth paper, Bilba et al 4 evaluate sugar cane bagasse, a by-product and renewable resource, as mineral replacement and as reinforcement in cementitious paste. When ordinary Portland cement is partly replaced by natural pozzolan and bagasse ashes, a ternary binder is obtained.…”