Durability of date palm fibres and their use as reinforcement in hot dry climates

This paper concerns the durability of male date palm surface fibres (MDPSF) immersed in three alkaline solutions: calcium hydroxide, sodium hydroxide and Lawrence solution with a pH ranging between 12.5 and 12.95. In addition the durability of MDPSF as reinforcement in small scale concrete beams has been studied. The concrete specimens were cured for six months in two different ways: 28 days in water followed by curing in wet chamber; and 14 days in water followed by a hot dry environment. The durability of MDPSF is evaluated by the loss of tensile strength and elongation, occurred over time, of fibres submitted in alkaline solutions using the tension test. The durability of the fibre-reinforced concrete is estimated by the variation of the first cracking strength, maximum post-cracking load and the maximum load ratio obtained from bending test. Some scanning electron microscopy (SEM) images of fibres extracted from alkaline solutions, as well as from the matrix at the fibre–matrix interface, have been examined to characterize the microstructure of the fibres. The results of the investigation have shown that MDPSF are easily attacked by alkaline solution under both curing conditions. Hence the durability of MDPSF-reinforced concrete is poor.