Volumen 16 (2021): Heft 1 (June 2021)

The calibration chamber of the 3SR INPG laboratory in Grenoble used to study the point stress and the shear, mobilized along the shaft of the pile under monotonic axial loading. The physical model used for the various tests is a standard mini-pile installed in standard sand: Fontainebleau sand. This article explores the induced effects on the bearing shear capacity of the pile as a function of time, up to the point of failure, under different monotonic loads applied after periods of rest. A series of monotonic static loading tests, were performed on the pile. Tensile load tests, uplift, were performed before and after each series of static loads. A Lateral stress was observed at the start of the experiment at the pile-soil interface. It disappears as soon as the pile is driven into the soil, due to the dilatancy of the soil. This observed phenomenon is probably due to a decrease in non-mobilized lateral friction at the start of the experiment. A study of this phenomenon will be described in this article. Likewise, the effect of the mechanical characteristics of the soil and the effect of time will be presented in the bearing capacity of the soil, as well as the total bearing capacity of the pile under monotonic static loading.

The current study aims at highlighting the fresh and hardened characteristics of self-compacting concrete (SCC) incorporating marble powder and steel fibers at different sizes. Seven SCC mixtures were investigated with two different types of steel fibers were used in combination at different proportions, keeping the total fiber content constant at 72 kg/m3, 400 kg/m3 of cement and 80kg of marble powder was substituted by weight of fine and coarse aggregate. Slump flow time and diameter, L-Box, and sieve segregation test were performed to assess the fresh properties of the concrete. Compressive strength, splitting tensile strength, fracture energy and ultrasonic pulse velocity of the concrete were determined for the hardened properties.

The results indicate that marble powder with high fineness can be used with steel fiber to produce reinforced self-compacting concrete (RSCC) with an improvement in the hardened properties, even though there is some reduction in the fresh properties because of the use of large steel fibers.

Taking into account the soil-structure interaction in the design of structures is a very decisive factor in the safety and durability of these structures. Several studies have been carried out in this direction to better describe the behavior of soil-structure interfaces.

This paper presents an analysis of the maximum and minimum displacement as a function of the number of cycles of a bored pile under the effect of cyclic tensile loading. In this study, the cyclic stiffness and the displacement of the pile are expressed by a simple formulation according to the cyclic parameters, based on the exploitation of the experimental tests carried out by Benzaria (2013) on a bored pile.The proposed formulation well predicts the displacement of piles in cyclic tensile. The approach presented in this paper can be used to evaluate the maximum and the minimum displacement of the head of pile foundation subjected to large number of shear cycles.

Coherent soils are very responsive in nature and are part of many human activities. They change in volume considerably with changes in moisture content. These soils are characterized by the presence of a large proportion of highly active clay minerals of the montmorillonite group which are responsible for the pronounced volume change capability of the soils. The objective of this paper is to investigate the influence of different polymers on the plasticity properties of swelling clays. A study of their physicochemical properties based on an experimental protocol in the laboratory was carried out, the results obtained showed that the addition of the different types and amounts of polymers favourably influences the behaviour of expansive soils and reduces swelling.

This article presents the results of the possible utilization of construction waste as the filler substitute in the production of cement composites. It describes the representation of the individual material components in the sample of mixed construction recyclate with the fraction of 0/4 mm. It also presents the results of a grain analysis of mixed construction recyclate, experimental formulations of cement composites, test specimen preparation procedure, results of compressive and flexural strength tests of the individual mixtures which were tested after 28 and 90 days.

This present study aims to examine the possibility of using the dune sand which is abundant in Algeria in the manufacture of mortars having sufficient physical and mechanical performances to exploit them in different applications in the field of construction of buildings. The improvement of the mortars based on dune sand was made through the addition of crushed wastes of ceramic tiles and red clay brick. The formulation of mixtures is based on the substitution of dune sand with crushed wastes at different weight contents; 5, 10, 15, 20 and 25%. The W/C ratio is fixed at 0.7. The results obtained show that the incorporation of these additions improves the compactness, the mechanical strengths and the sulphate resistance, and enhancement the dynamic modulus of elasticity with 15% ratio of waste incorporation. Further to this, it was also observed that the inclusion of the used wastes with determined percentages can provide physical and mechanical performances exceed that given by the mortar made with alluvial sand, which demonstrate their effectiveness to the improvement of the various properties of the mortar.

Considering Soil reinforcement techniques have been rapidly developed because of its efficiency in geotechnical engineering. The goal of this experimental work is to improve the characteristics of a collapsible soil with polyethylene fibers in the aim of reducing the number of plastic bottles thrown in nature and with natural materials such as sisal fibers. Polyethylene fibers contents in mass were used in this investigation, namely: 5%, 10% and 15%; Sisal fibers contents: 0.5% and 1% respectively. Oedometer apparatus is used to study the reinforcing fibers effect on the Collapse Potential, and direct shear box is used to determine the intrinsic characteristics of this treated soil. Results show that when the fiber reinforcement is combined with other processing procedures such as compaction and the addition of APC cement decrease the collapse potential until a non-collapsible soil is obtained.

Using of waste materials and secondary products from other industries in building industry to manufacturing building materials is one way to the sustainability. However, application of various waste requires serious monitoring and investigation of the safety of the new composites. Heavy metals presence and their releasing from the building materials can pose a potential risk to the environment and human health. The paper presents the results of a study of concrete composites with blast furnace granulated slag and special hybrid cement based on secondary mineral admixtures in relation to their heavy metals leachability. Selected metals (Cr, Pb, Ba, Ni, As) have been analysed using long-term tank and cyclic testing. The concretes with slag addition and hybrid cement proved more intensive releasing of analysed metals compared to the reference concrete. The aggressiveness of extracting media was strongly affected not only by pH but by the quantity of the ions presented in the liquids before the experiment as well. Although the leached quantities were not extremely high, results confirmed the need to monitor the building products with the incorporated waste.

The most discussed topics in the 21st century at the global level include climate change, carbon neutrality, digitization and globalization. They have impact on the lives of all people, the quality of the environment in which we live, the health of the whole population, the development of cities and urban areas, the development and direction of industry and its new technologies, and last but not least, they shape humanity to which they are giving direction. Regional self-governments, as elementary elements of the state, therefore play a key role in achieving the EU’s environmental and climate change goals and objectives. The issue of digitization is changing human approaches to address global challenges, including the call for a proper assessment of the impacts of climate change on urban and suburban areas as a tool for identifying and subsequently integrating early actions. Digital technologies and their potential can make a huge contribution to sustainable development, and to re-addressing global challenges. According to the OECD, in an era of digitization, climate change and ageing, it is important to see cities as engines for economic growth.

In this paper a finite-element analysis was carried out using Plaxis^2D software to model a vertical cut reinforced by nails. Optimization of the effect of three input parameters on stability design is a key element of the analysis. We compare results obtained by three techniques of design optimization; Taguchi’s Design of Experiment (DOE), Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The effect of three input factors on stability design was considered: nail length to wall height ratio (A), nail inclination (B) and vertical spacing (C). By altering the parameter variables, the design served to build and acquire a statistically significant mathematical model for optimizing soil nailing wall parameters. The aim is to minimize a single objective function of safety factor and identify the optimal parameters of design among all possibilities. DOE method and result analysis were carried out using MINITAB 18 software, while GA and PSO algorithm analysis were implemented by coding in MATLAB. According to the results, it was found that 9m of length, 2m of vertical spacing and 10° of inclination is the optimal combination minimizing safety factor. The results produced from this study show that all three techniques arrive at the same optimal combination of minimum response.

Concrete is as a significant building material. Due to the fact that it is possible to incorporate by-products and industry waste into its structure, concrete represents an important sustainable material. Steel slag has a great potential for its reuse in concrete production. Despite that it is subject to volume changes over time, it can be used in concrete as a cement replacement or as a substitute for natural aggregates. The paper is focused at investigation the concretes with steel slag as a substitute of natural gravel aggregate of 4/8 mm and 8/16 mm fractions. In addition, a life cycle assessment within the system boundaries cradle-to-gate was performed. Results showed that some samples with slag have better mechanical parameters than samples with natural aggregate and significantly affect the utilization rate of non-renewable raw materials and reduce the overall negative environmental impacts of concrete up to 7 %.

The study of the response of deep foundations under different types of stress was the subject of several studies, but it is always very useful to understand the phenomena accompanying the behavior of these foundations in contact with the ground, and to propose simple and more efficient approaches.

This paper presents a numerical analysis of the response of a pile foundation subjected to axial load with taking account the soil-pile interaction. The analysis of the composite pile–soil system was performed using the Finite Element Method (FEM) using software Plaxis 3D tunnel. The pile- soil analyses and design is an interaction three dimensional problem, wherein, the applied load is transferred by a complicated interaction process between the piles and the soil. To reduce the analysis volume of interaction problems, it is necessary to have a relatively simple design procedure so that the preliminary design can provide adequate but reasonably accurate data for the final analysis. The method consists to replacing two configurations of pile group with a single equivalent pier of the same length and an equivalent diameter. This equivalent pier is described by his material properties that result of the homogenisation of the piles and the surrounding soil. In this study, two types of symmetric and asymmetric pile group configurations are examined. The numerical results of settlements were compared with the field measurements collected from case history, which showed good agreement. The pier equivalent method can decrease the interaction factor of 2×2 pile groups by 16% than the interaction factor of single pile group.