Date Palm Fiber Composites in Hot-Dry Construction and Building

Abstract

Southern regions of Algeria are characterized by hot and dry climate over period which extends eight months from March to October. Temperatures in summer reach over 45° C in the shade. Actually, modern buildings in these regions are made in cement materials (concrete and mortar) these buildings are weak, not durable and present a lot damages caused by low resistance to cracking and thermal shrinkage. In addition, these cement materials present poor thermal insulation. It is therefore necessary to reinforce them with fibers. Several fibers can be used for that, but for economic and environmental reasons vegetable fibers from the by-products of date palms can fulfill the purpose in a good way. Because their treatment is inexpensive and such valorization contributes favorably to the protection of palm groves against fires, often started by this waste stored in an anarchic manner. The reinforcement of building materials with palm fibers, especially concrete or gypsum, is relatively a newly research topics. In the literatures several researches discuss the reinforcement of building materials with steel, carbon or polymer fibers. On the other hand, only a few scientific works are devoted to vegetable fibers, especially palm fibers. In this chapter it will be investigated the mechanical, physical and thermal properties of certain local building materials (gypsum and earth (clay plus dune sand)) that exist in abundance in the southern regions of Algeria, and their reinforcement by date palm fibers and concretes and mortars reinforced by the same fibers. In addition, it will be presented the mechanical characteristics of the used date palm fibers. This study focuses on the improvement of mechanical and thermal performances of the last materials. It aims the characterization of the newly adopted materials and eventually their use in construction in hot and dry climate. Firstly, the results showed that among the four types of date palm fibers: male palm, Elghers, Deglette Nour, Degla Bida (local names), the male date palm fibers have the best mechanical performances in terms of resistance tensile and deformation at break. Second, for concrete reinforced with date palm fibers and initially kept in a 14-day wet cure, a volume fraction of 3% with fibers 6 cm long was very beneficial for improving mechanical performance. Under the last wet cure conditions, it was noted that beyond 6 months the durability of the fibers was badly affected by the alkaline hydraulic products of Portland cements (CPJ-CEM II/A 32.5). To resolve the exposed problem, cement with low alkalinity (Portland cement composite (CPJ-CEMII/B 42.5)) plus 10% by mass of fly ash was used. This treatment got better the durability of fiber in cement matrix. Third, it was shown that clay brick with (60% clay + 40% sand + 3% fiber) exhibited the best thermal performance with acceptable mechanical properties. And finally, the reinforcement of the gypsum by date palm fibers (5% by mass of separated fibers and 4% by mass of fibers in mesh layers) have gave the best thermal and mechanical performances. In conclusion, Africo-Asian countries, including Algeria, possess a great wealth of renewable bio-resources. Vegetable fibers especially those obtained from by-products of date palm and the variety of local construction materials can be used to develop industries interested by newly eco-friendly reinforced materials having good mechanical and thermal characteristics. This study wishes to popularize the valorization of date palm by-products in construction materials and proceed to the industrial stages. Consequently, contribute to a sustainable development in these regions of the world.