Study of the Effect of Waste Glass Fibers Incorporation on the Collapsible Soil Stability Behavior

Soil collapse remains a major issue affecting structural foundations, particularly in arid and semi-arid zones where humidification is a key factor contributing to the collapse. Much research has been devoted to identifying treatment methods which enhance the stability and load-bearing capacity of this type of soil. This paper investigates the potential advantages of the addition of milled glass fibers (Fg ). Soil samples were prepared at different compaction energies and various water contents, then treated with different percentages of milled glass fiber, before being submitted to the simple consolidation odometer test. The results obtained in this study showed that soil samples treated with an optimal dosage of 6% of milled glass fibers compacted at 60 blows and humidified at 6% of moisture content. This represents an improvement in the stability of the soil, reducing the collapse potential (Cp) from 11.95% to 1.62%. This treatment method produces soil which can be classified as a moderate risk foundation soil according to the Jennings and Knight evaluation metrics (1975). Keywords: collapsible soils, arid zones, fiberglass, odometer test

The Influence of the Nature of Different Sands on the Rheological and Mechanical Behavior of Self-compacting Concretes

Self-compacting concretes represent a new advance for concrete construction because they offer many advantages from the economic, technical and social point of view. They are very fluid concretes, which are put in place without vibration. When pouring into a formwork, tightening a BAP is ensured by the simple effect of gravity. Thanks to their formulation, they offer exceptional flow characteristics and filling formwork while resisting perfectly segregation. Homogeneous and stable, they have resistances and durability similar to those of traditional concretes of which they are differentiated by their properties in the fresh state. The use of self-compacting concrete reduces the noise nuisance, as well as the hardness of the work. This research work is part of a policy of contributing to the improvement of the properties of self-compacting concretes prepared from local materials in the M’sila region. In this study, we are interested in obtaining the most suitable concrete formulation for the different local materials of the M’sila region. Our study is directed towards the effect of the following parameters on the physico-mechanical properties of the composite such as: dynamic segregation, spreading diameter as well as mechanical strengths (compression, traction). It is therefore a question of determining the criteria to be imposed on these parameters, in order to lead to the construction of a self-compacting concrete characterized by  an acceptable resistance. The experimental results of compressive strengths show significant behaviors between BAP and BV. They allowed to distinguish a resistance gain between 15.11 and 49.28, this gain is explained by a rehydration of the cement matrix due to the migration of the water through the pores for the BAP, but also to better binding properties of the hydrates forms. Keywords: SCC, Rheological behavior, Mechanical resistance, Binde

The Combined Effect of the Initial Cure and the Type of Cement on the Natural Carbonation, the Portlandite Content, and Nonevaporable Water in Blended Cement

The aim of this work is to better understand the physical and chemical phenomena involved in hydrated mix (clinker + addition) during the natural carbonation process, to characterize cement with supplementary cementitious materials (SCMs) under various curing environment. The prepared cement pastes were characterized by thermogravimetric analysis. The results showed a considerable influence of the environment on the properties of mortars and cement and a perfect correlation between compressive strength, natural carbonation, nonevaporable water, and portlandite content. It was observed that the reduction of the curing period makes the mortars more sensitive. The kinetics of process was evaluated from Ca(OH)2 content and nonevaporable water contained in mortars. These two parameters reflect the hydration progress of the water/cement ratio studied. The weight loss due to Ca(OH)2 decomposition, calculated by DTA/TG analysis, shows the effect of the pozzolanic reaction and the natural carbonation. The supplementary cementitious materials (SCMs) play a considerable role in the slowing down of the aggression environment

Experimental Investigation on the Properties of a Recycled Aggregate Concrete Based on Waste of the Industrial Mineral Additions

This study investigates the possible effects of incorporating different industry wastes during manufacturing of concrete, with percentages ranging from 0% to 30%, and assesses the influence of these combinations (mineral additions and recycled aggregates) on the properties of a recycled concrete comprised of these two main constituents products. Recycled concrete samples with different combinations of mineral additions at various dosages were used to determine these properties in the fresh and hardened states. The ”Design-expert” methodology was used to analyse the results after 7, 14 and 28 days, identifying correlations and the effects of the different variables. The results obtained showed the advantageous effect of incorporating the pozzolana and slag into the concrete mixture at dosages of 15% and 30%, they also demonstrated the low optimal percentage of marble fillers of 5%. These findings suggest that replacing clinker with industrial waste could limit the dust and CO2 emissions into the atmosphere during concrete manufacture, offering environmental advantages as well as conserving the natural resources of aggregate recovery from C&D wastes. Keywords: environmental concrete, mineral additions, recycled aggregate, design expert method

Optimization of Cellular Concrete Formulation with Aluminum Waste and Mineral Additions

The paper aims to study cellular concrete with a new approach of formulation without an autoclave, with the use of aluminum waste and incorporation of mineral additions into the sand and evaluate its physical and mechanical properties. In this experimental study, two types of cellular concrete are prepared, based on crushed and dune sand with the incorporation of 15% of the slag and 10% of pozzolana, as sand replacement. An experimental program was performed to determine the compressive strength at 28 days, the density and thermal conductivity of the confected cellular concrete. The obtained results showed that concretes prepared with crushed sand developed better mechanical resistance compared to the dune sand. It is also noted that the concretes containing the mineral additions provide a substantial increase in compressive strength in particular slag. Furthermore, cellular concretes with sand dunes offer better thermal conductivity, compared to those with crushed sand. The use of the additions reduces the Water/Binder (W/B) ratio and leads to a lower thermal conductivity regardless of the used sand nature. The outcome of the present study here in could present a modest contribution for the production of cellular concrete with local materials in particular dune sand, active mineral addition and aluminum waste. The physical and mechanical properties obtained from this new composition are estimated acceptable compared to those of the industry-prepared cellular concrete product. Doi: 10.28991/cej-2021-03091721 Full Text: PD

Chemical activation effect on the mechanical response of mortars based on dune sand

The main qualities sought for a mortar are usually; the high compactness, good sealing or impermeability, better mechanical strength and long-term durability. The different methods of accelerating setting and hardening of the mortar as well as the desired characteristics are of great importance with regard to the use of mortars and their different applications in civil engineering. This work is a contribution to improving the properties of mortars at fresh and hardened state by different activation techniques in particular chemical alkaline activators method. The properties of chemically activated mortars using alkaline solutions (KOH and NaOH) at dosages of 0, 2 and 4% was investigated in this experimental program using a based cement matrix with dune sand and blended cement type CEM II/ B grade 42. The results obtained showed the beneficial effect of the chemical activation modes mainly, an improvement of the mechanical response (compressive strength) at young age and in the long term

Characterization of a sustainable mortar based on mineral additions and prepared sand

The present study is to investigate the physical and mechanical properties of the prepared sand mortars, mainly based on the local Oued Souf sand region south of Algeria, this in accordance with standard sand grading. The principal aim of the research is to replace the restricted fine part between (0.08and 0.16 mm) which is of the order 15% and to substitute it with additions active slag (S) and inert glass powder(GP) with dosages of 5, 10 and 15 % and maintain the rest of the granular fractions of the sand studied fixed. Thus, to see and analyze the influence of these additions on the physical properties and in regards the mechanical performances of confected prepared sand mortars. The results showed the advantageous effect of replacing the said prepared sand with two additions (slag and glass powder) on physical, mechanical properties mortars based on this local sand by improving the performance of these cement products, especially at an optimal percentage of 10%

Characterization of a sustainable mortar based on mineral additions and prepared sand

The present study is to investigate the physical and mechanical properties of the prepared sand mortars, mainly based on the local Oued Souf sand region south of Algeria, this in accordance with standard sand grading. The principal aim of the research is to replace the restricted fine part between (0.08and 0.16 mm) which is of the order 15% and to substitute it with additions active slag (S) and inert glass powder(GP) with dosages of 5, 10 and 15 % and maintain the rest of the granular fractions of the sand studied fixed. Thus, to see and analyze the influence of these additions on the physical properties and in regards the mechanical performances of confected prepared sand mortars. The results showed the advantageous effect of replacing the said prepared sand with two additions (slag and glass powder) on physical, mechanical properties mortars based on this local sand by improving the performance of these cement products, especially at an optimal percentage of 10%

Study of the mechanical behavior and durability of mortars based on prepared sand

Sand occupies a great proportion of the cementitious matrix product and in particular mortars. Hence, the study of fine aggregates used for concrete and mortar in general, deserves to be objects of research including sand which has always been considered as inert material, whose role is exclusively physical. The study of mortars performances based on prepared sand to assess the effect of the type and rate of substitution of mineral additions pozzolana and blast furnace slag of a natural sand fine fraction (sieve diameter less than 0.16 mm) is seen as the main objective of the present experimental research work. The natural sand replaced size is less than 160 µm and for rheological reasons the maximum replacement rate of natural sand is limited to 10%. The results obtained show a significant improvement of the mechanical properties for the mortars based on the new activated sand. With regard to durability tests of HCl and H2SO4 acids chemical attacks, the substitution of the quartz by active mineral additions in the sand-size skeleton allows an advantageous reduction in loss of resistance up to 50% and a mass gain around 75%

The Influence of the Nature of Different Sands on the Rheological and Mechanical Behavior of Self-compacting Concretes

Self-compacting concretes represent a new advance for concrete construction because they offer many advantages from the economic, technical and social point of view. They are very fluid concretes, which are put in place without vibration. When pouring into a formwork, tightening a BAP is ensured by the simple effect of gravity. Thanks to their formulation, they offer exceptional flow characteristics and filling formwork while resisting perfectly segregation. Homogeneous and stable, they have resistances and durability similar to those of traditional concretes of which they are differentiated by their properties in the fresh state. The use of self-compacting concrete reduces the noise nuisance, as well as the hardness of the work. This research work is part of a policy of contributing to the improvement of the properties of self-compacting concretes prepared from local materials in the M'sila region. In this study, we are interested in obtaining the most suitable concrete formulation for the different local materials of the M'sila region. Our study is directed towards the effect of the following parameters on the physico-mechanical properties of the composite such as: dynamic segregation, spreading diameter as well as mechanical strengths (compression, traction). It is therefore a question of determining the criteria to be imposed on these parameters, in order to lead to the construction of a self-compacting concrete characterized by  an acceptable resistance. The experimental results of compressive strengths show significant behaviors between BAP and BV. They allowed to distinguish a resistance gain between 15.11 and 49.28, this gain is explained by a rehydration of the cement matrix due to the migration of the water through the pores for the BAP, but also to better binding properties of the hydrates forms. Keywords: SCC, Rheological behavior, Mechanical resistance, Binde