Elaboration and characterization of a bio-composite destined for construction

The composite materials industry evolves and grows continuously by introducing new materials and technologies. As an alternative for mineral materials, materials of natural origin (especially vegetable) started to be used. Due to their desirable characteristics such as low environmental impact, low cost, biodegradability, low density and good mechanical properties, the vegetable fibers have been extensively used as reinforcement in cement-based composite. Among the vegetable fibers family, date palm fibers (DPF) generated from the annual crop taking of date palm trees represent a considerable amount of vegetable fibers which normally considered as a waste or it is used for applications of daily life in low values of the total products. Date palm mesh fibers (DPMF) is a type that belong to these fibers, it is a cross mat of single fibers surrounding the stem of the date palm tree. The valorization of the DPMF is a major step toward the production of green lightweight cement-based materials and reducing the cost of materials destined for construction sector. The present thesis exposes an experimental investigation on the use of DPMF as reinforcement for cementitious materials. For this purpose, the influence of the DPMF’s inclusion with multiple fractions on the fresh properties of a cement mortar was studied. Furthermore, the mechanical performance of cement mortar composites has been examined through investigating the compressive, flexural and fracture behaviors. The results obtained show that the fresh properties of the reinforced mortar composites were not influenced after adopting such a mixing process in which the DPMF were introduced in wet state. The selected physical and mechanical properties of the cement-based mortar composites showed a decrease with the gradually increase of fibers content. Nevertheless, the inclusion of DPMF improves the post-peak behavior, the ductility and delays the failure of cementitious composites compared with plain mortar specimens. Also this study has shown an interesting fracture properties obtained for low content of DPMF ( 2% by volume). Previous research works reported a similar fracture toughness value

Ultrasonic Evaluation of Cement-Based Building Materials Modified Using Marble Powder Sourced from Industrial Wastes

This paper presents an experimental study on the assessment of the cement-based materials properties made with marble powder (MP) at different replacement ratios (0%, 5%, 10%, and 15%) of cement by using the ultrasonic pulse velocity (UPV) test. The used MP has a Blaine fineness similar to that of Portland cement. The physical and the chemical characteristics of Portland cement and MP were determined. To determine the UPV values, cubic specimens (50 × 50 × 50 mm3) of cement paste and mortar were prepared and cured either in air at a temperature equal to 22 ± 2 °C and relative humidity equal to 20 ± 1%, or in water at a temperature equal to 20 ± 1 °C. The experimental tests including the UPV, the compressive strength (fcd), and the apparent density (ϒad) were conducted at 3, 7, 28, and 65 days, the relationship between each of these parameters were presented. Additionally, economic performance of cement and waste MP used in this study was performed. The results show that the use of MP as partial replacement of cement causes a decrease in the compressive strength and apparent density in both curing conditions. In addition, the results show a good relationship between the destructive test and non-destructive test adopted by UPV

The influence of date palm mesh fibre reinforcement on flexural and fracture behaviour of a cement-based mortar

The aim of the present paper is to investigate both flexural and fracture properties of a cement-based mortar reinforced with Date Palm Mesh (DPM) fibres. In particular, three-point bending tests on DPM fibre-reinforced specimens (with different fibre volume fractions) are performed. On the basis of the experimental results, the value of flexural strength is computed as a function of the peak load according to the UNI Recommendations, whereas the value of fracture toughness is analytically determined according to the Modified Two-Parameter Model (MTPM) recently proposed by some of the present authors for quasi-brittle materials