This experimental work investigates the impact of substituting part of the conventional aggregates with rubber aggregates on certain characteristics of the cement concretes. This incorporation of rubber aggregates resulting from cutting worn tires in practical sizes decreases the mechanical resistances of the concretes while improving slightly the fluidity of the tested mixtures. The effect of these aggregates on the shrinkage of the concretes at an early age is appreciable and even very interesting for the concretes used, for example, in road construction. This technique of cutting worn tires without any further treatment makes it accessible to everyone which helps not only in saving the environment by getting rid of this cumbersome waste but also in saving traditional aggregates.

RI~SUMI~L'emploi d'additions mingrales en cobroyage avec le clinker peut permettre d'amgliorer les performances des b~tons de sable et de rgduire la quantit~ consommge de ciment. Un sable dunaire est m~lang~, en proportions variables, avec un clinker pour obtenir des liants cobroygs utilisgs pour composer le bgton de sable. Aim de sgparer les effets de la finesse du liant de ceux du dosage, un plan d'expgriences en deux phases a gtg suM. Dans un premier temps, on quantifie la finesse de mouture du liant cobroy~, puis on 6tudie l'influence des diff4rents paramitres sur les caractgristiques mgcaniques des bgtons de sable. On caractgrise en particulier le degrg d'activitg des ajouts sableux qui peut se rdvgler significatif et conduire ?t l'gconomie d'une certaine quantitg de ciment. ABSTRACTMineral additions can be mixed with the dinker before the grinding process. Thus, one obtains a 'coground' binder which can allow some reduction in the cement ratio. Some dune sand is added, in variable proportions, to the clinker, such as to obtain a coground binder from which different sandcrete mixes are defined. To distinguish the effects of the binder fineness from those of the addition ratio, a two-stage experimental design process has been followed. In a first stage, the fineness of the coground binder has been quantified. Thereafter, the influence of several parameters (fineness, addition ratio, water/binder ratio) on the mechanical properties has been evaluated and modelled. The degree of activity of the mineral additions has been confirmed. It can lead to some gain in the cement content.

It is well known that the reinforcement of the Soil is considered as a solution to its stability problems. This technique ameliorates the mechanical and physical comportment of the soil. Based on this, this research paper aims at investigating the behaviour of a specific type of dried-cemented-sandy soil reinforced with discrete elements such as polypropylene fiber basically through experimental tests. The latter are a series of consolidated drained triaxial tests which were carried out on samples of sand that are prepared with 0, 3 and 6% of cement, reinforced with 1% of polypropylene fiber (12, 18 mm) randomly distributed. Furthermore, those contents are measured by the volume of dry sand. In addition to these tests, a parametric study has also been conducted on a road embankment using a finite element program such as Plaxis 2D in order to observe the variation of different parameters like safety factor and the displacements (Ut, Ux, Uy). The test results showed that the addition of cement and polypropylene fiber of different accommodations increased both cohesion and friction angle of sands while the numerical results indicated that the presence of these additions improved the safety factor and decreased significantly the displacements.

This work mainly relates to promoting the use of concrete based on sand and the incorporation of rubber aggregates (0-1mm) from recycling of used tires in volume substitution of sand with rates of 10, 20 and 30% in order to obtain materials with low environmental impact. In order to meet this objective, an experimental approach was carried out, which consisted in incorporating different percentages of rubber aggregates in the formulation of sand concrete. These concretes are characterized in the fresh and hardened state in order to study the effect of adding these rubber aggregates on the properties of self-compacting sand concrete. The results found show that the fluidity of the SCSC (expressed by spreading with the Abrams cone and the flow at the V-Funnel) improves with the increase in the dosage of rubber aggregates and these values are located within the recommendations of the French Association of Civil Engineering. They also show that rubber particles can improve certain desired technical characteristics such as ductility.

In the last few decades, important attention was given to infill masonry panels due to their worldwide uses. Many experimental and numerical studies were conducted to study their effect on the behavior of RC frames. In general, three modeling strategies are widely applied to model infill masonry, namely, micro-models, meso-models, and macro-models. This study investigates the accuracy of the width models to predict the behavior of masonry infills using the meso-modeling technique. To this aim, the masonry infills are modeled as an equivalent homogenized diagonal element in order to represent the diagonal action of masonry infills. The width models used to determine the width of the diagonal strut are used in meso-modeling. In addition, the study contains comparisons between different modeling techniques to predict the global behavior of the infilled frames. Experimental tests conducted on two infilled frames from the literature are considered to calibrate the numerical simulations. The results indicate that the micro-modeling approach gives a good agreement with the experimental tests in terms of lateral force and deformation shapes, the related errors varying between 0.12 and 2.8%. Using single strut models, the differences between numerical and experimental results vary from 1.1 to 20%. On the other hand, the errors obtained from multiple strut models are varying between 9 and 40%.