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This paper deals with experimental and numerical investigations of the composites damages with ductile and fragile reinforcement under quasi-static indentation loading. The main goal of the work is to increase the post-damage residual strength and ductility of thermoplastic composite. Two types of composite laminates with polypropylene (PP) matrix are tested: glass fibre laminate (GFPP) and steel fine wire mesh laminate (SWPP). The specimens are [0° 90°]2s stacking sequence and prepared by using a compression moulding technique. Quasi-static indentation tests were performed with two distinct penetration scales under low velocity (1.2 mm/min). The diameter of the hemispherical indenter is 16 mm. The failure mechanisms of composite layers were examined by the field emission scanning electron microscope (SEM). The results show that the failure mode of SWPP laminates is principally dominated by the plastic deformation component. In contrast, the GFPP laminate exhibits a fragile behaviour which is related to the fragile failure of glass fibres. In addition, the SEM shows that matrix cracking, fibre breakage, debonding and fibre pull out are the major damages observed around the indentation area. A model based on the combined use of plasticity, damage and fracture, was developed and applied to simulate quasi-static indentation behaviour and predict the resulting damage.

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The present work deals with a unique in-service valuation of CSEB structures in Algeria. The inspection tries to bring out the impact of long time exposure under different and opposite climate and micro-seismic contexts. The diagnosis methodology is inspired by the approach largely adopted for the rehabilitation of traditional architecture. It involves the compilation of the previous survey reports, visual inspection of the structures, in-situ and laboratory tests to assess the residual CSEB mechanical properties. The CSEB constructions are located in the coastal north and the desertical south part of Algeria and were exposed respectively to a long-term Mediterranean and Saharian climate. The results of the investigation show that the CSEB in the construction located in the northern region is increasingly altered by the humidity. As the relative humidity rises, the fouling layers grow over some level. The surface pitting which is the consequence of long exposure to the wetting/drying cycles is also observed. The outer surfaces of the walls were honeycombed which reduce drastically the block resistance against the abrasion test. In some cases, differential erosion appears in the front of the walls, which indicates that the alteration does not proceed at the same rate from one area of the block to the other. However, owing to highly cementitious mortar used to join the earth blocks, the edges and corners remain unchipped. In the southern region where the arid climate dominating, the degradation of the CSEB is less prone to water attack but roughly exposed to the effect of the winddust frequent in this region and to the unawareness of the population. The paper presents also some recommendations to improve the earth construction durability with CSEB technique.