Strength and durability of mortar made with plastics bag waste (MPBW)

The aim of this study is to explore the possibility of re-cycling a waste material that is now produced in large quantities, while achieving an improvement of the mechanical properties and durability of the mortar. This study examines the mechanical properties and the durability parameters of mortars incorporating plastics bag wastes (PBW) as fine aggregate by substitution of a variable percentage of sand (10, 20, 30 and 40 %). The influence of the PBW on the, compressive and flexural strength, drying shrinkage, fire resistance, sulfuric acid attack and chloride diffusion coefficient of the different mortars, has been investigated and analyzed in comparison to the control mortar. The results showed that the use of PBW enabled to reduce by 18–23 % the compressive strength of mortars containing 10 and 20 % of waste respectively, which remains always close to the reference mortar (made without waste). The replacement of sand by PBW in mortar slows down the penetration of chloride ions, improves the behavior of mortars in acidic medium and improves the sensitivity to cracking. The results of this investigation consolidate the idea of the use of PBW in the field of constructio

FRP-confined short concrete columns under compressive loading : experimental and modeling investigation

This study introduces the results of an experimental investigation on the behavior of the circular columns of concrete under a load of axial compression, confined by an envelope of composite materials (carbon fiber and glass fiber). The composite used is a FRP glued in surface with epoxy resin. The specific objectives of this study are: verifying the applicability of this method of reinforcement of the columns to improve the behavior of concrete from the point of view strength and ductility, seeing the influence of composite materials type used, and confronting the experimental results acquired with different models developed on one hand and on the other hand with empirical formulas developed by other researches. Two models were developed to represent the structural behavior of the tested samples based on the calibration of the experimental results and criterion of Mohr—Coulomb failure. The validity of the results acquired numerically is based on a comparison with experimental results as well as with empirical formulas develope

Multiple confinements of concrete columns by various embedded composite grids

This study exhibits the experimental results of axial compression tests on concrete cylinders, circumferentially confined by the set-up of the composite grids arranged inside the cylinder, according to several combinations of circumscribed grids. The main aim is to verify the applicability of this method and then to quantify the contribution to strength improvement due to confinement as well as its influence on the rupture mode under axial compression. The test results of loading carried out on cylindrical concrete specimens, confined by alveolus composite grids arranged inside the section, show that it is possible to substantially increase the ductility of the columns, and in certain cases, their strength. It is also noted that the rupture of confined concrete is highly influenced by the presence of the grids depending on the configuration and the shape of the cells (rhombus or hexagonal) constituting the composite grid. The experimental results are compared with the theoretical model dat

Effectiveness of repair on damaged concrete columns by using fiber-reinforced polymer composite and increasing concrete section

This research is a contribution to work on strengthening and repair of reinforced concrete structures, it presents a comparative study between two methods of repairing damaged concrete with an experimental investigation on the behavior of specimens initially pre-damaged up to intense cracking, repaired by increased concrete section and by bonding a carbon fiber reinforced polymer. In our study, the concrete columns with square sections of (15 × 15) cm2 and a height of 30 cm are tested under uniaxial compression loading up the damage, these columns have been repaired, using both methods, they are tested again and their behavior has been studied. Based on the criterion of Mohr–Coulomb failure, a model was developed for each method to validate the different results obtained experimentally. The experimental results show that the method to repair damaged concrete by carbon fiber reinforced polymer has a good substrate adhesion, which offered a great improvement in strength and ductility compared to the method by increased concrete section. The experimental results have been compared with the theoretical models, a good correlation was obtaine

Strength and compressive behaviour of ultra high-performance fibre-reinforced concrete (UHPFRC) incorporating algerian calcined clays as pozzolanic materials and silica fume

This paper presents results of an experimental study which investigates the effect of four pozzolan additions made from various by-product materials on physical and mechanical properties of ultra-high performance fibre-reinforced concrete (UHPFRC) compared with the silica fume (SF): waste bricks (WB) and three types of metakaolin (MK) as calcined clays at 750 °C: calcined clay of Djbel Debbagh quality 3 (DD), calcined sludge incineration at the manufacture of paper (PS) and calcined silt of dams (SD) having median particle sizes less than 45 μm are used as addition. For each addition, five percentages of steel fibres (1, 1.5, 2, 2.5 and 3%) were used to improve the performance of concrete. The results suggest that the use of WB, PS and SD has no significant effect on the compressive strength as compared with SF concretes. Calcined clay DD can be used as pozzolanic materials in making UHPFRC. This MK competes with the SF, after 28 days of curing, the concrete containing 25% of DD and 2.5% steel fibre presents a compressive strength of 179 MPa compared with the concrete containing 25% of SF and 2.5% steel fibre, which presents strength of 183 MP

Study of calcined halloysite clay as pozzolanic material and its potential use in mortars

In this research, we will try to understand the mechanisms involved in the introduction of calcined clays in substitution for a portion of cement in the manufacture of mortars. This experimental work focuses on the recovery of a clay type haloysite quality three, from eastern Algeria. This clay comes from a region called Djbel Debbagh hence its name (DD3). The main objective of this study is to see the influence of the activated clay by calcination with different percentages of 5, 10, 15 and 20% in substitution of cement, on the physical-mechanical properties and behaviour of mortars towards chemical attacks. The study of pozzolanic activity allows to optimize a calcinations temperature of about 750°C, the study of its mechanical performance has shown an improvement of strength. Finaly the results of the durability test showed a good performance in different environment

Effect of the heat curing on strength development of self-compacting mortars containing calcined silt of dams and Ground Brick Waste

The strength development of self-compacting mortars (SCM) containing calcined silt (CS) and ground brick waste (GWB) was investigated. The variables are the nature of addition (CS and GWB) in the binder and the heat curing at different temperatures (20 ºC and 60 ºC) at 7 and 14 days of curing. Two temperatures 20 and 60 ºC were applied to samples with intermediate levels (depending on the drying method applied to precast) for 18 hours in total. In this study, a Portland cement (CEMII), Calcined silt (750 ºC for 5 hours), ground waste brick, were used in the binders of SCM. The results show that the compressive strength to 14 days of mortars, increases with annealing (60 ºC) compared to that measured at 20 ºC. Also, values of compressive strength of mortars at 14 days that are close to those obtained without 28 days curing treatment. Indeed, a strength gain of about 20.5% and 27.3% was obtained respectively for the SCM with GWB and the SCM with CS. However, a small change in mass recorded for both types of mortars