Papers by Journal of Building Materials and Structures (JBMS)
Self-compacting repair mortars (SCRM) are particularly desired for the rehabilitation and repair ... more Self-compacting repair mortars (SCRM) are particularly desired for the rehabilitation and repair of reinforced concrete structures. The properties of SCRM can be improved by using chemical, mineral, polymer and fiber additives. In limestone quarries, considerable quantities of limestone fine powder are obtained during the process of crushing rock. These fine powders are being collected and their utilization is a big problem from the aspects of disposal, environmental pollution and health hazards. The introduction of limestone powder as cement and sand replacement present interesting possibilities to reduce the cement cost production, CO2 emission and the conservation of natural resources. The effects of limestone powder content in crushed sand on the properties of SCRM are not studied. An experimental study was undertaken to find out the effect of limestone powder content on fresh and hardened properties of SCRM. SCRM mixtures were prepared using crushed sand partially replaced with limestone powder at varying percentages up to 30%. Results indicate that the limestone powder as sand replacement significantly improves the fresh and hardened properties of SCRM with a content ranging from 10 to 15%. The use of limestone powder in repair mortar and concrete application would offer technical, economical and environmental advantages for concrete producers.
Addition of Nano-SiO2 (NS) to geopolymer composites has been studied through measurement of compr... more Addition of Nano-SiO2 (NS) to geopolymer composites has been studied through measurement of compressive strengths, Fourier Transformer Infra-Red (FTIR) and X-ray diffraction (XRD) analysis. Alumino–silicate materials are coarse aggregate included waste concrete and demolished walls with its cementing binder, cement kiln dust (CKD) used and can possess a pronouncing activation for the geopolymer reaction resulting from the high alkali contents within. Materials prepared at water/binder ratios in a range of 0.30: 0.40 under curing of 40 o C and 100% R.H, while the used activator is sodium hydroxide in the ratio of 2 wt. %. First, CKD is added in the ratio from 10 up to 50 wt., %, and the demolished walls was varied depending on the used CKD content, while using constant ratio of waste concrete (40 wt., %). Second step, depending on the optimum CKD ratio resulted from the first one (40 wt. %), so the control geopolymer mix composed of CKD, demolished walls and waste concrete in the ratio (40:20:40, wt %). NS partially replaced waste concrete by 1 up to 8%. Results indicated that, compressive strengths of geopolymer mixes incorporating NS were obviously higher than those control one, especially at early ages and specially with 3%NS.
In this work, several reinforced self-compacting concretes were prepared by using three types of ... more In this work, several reinforced self-compacting concretes were prepared by using three types of fibers made of steel, polypropylene and glass, and three different types of mineral additions (marble powder, metakaolin and limestone powder). The water to cement ratio was kept constant at 0.34 and fibers were used in combination, keeping the total fiber content constant at 60 kg/m3. Slump flow diameter, L-Box, stability and air content were performed to assess the fresh properties of the concrete. Compressive strength, flexural strength, splitting tensile strength and ultrasonic pulse velocity of the concrete were determined for the hardened properties. Noteworthy performances were generally obtained, particularly in hardened properties for the self-compacting concretes prepared with steel fibers in association with polypropylene fiber and marble powder as mineral addition.
Performance of non-conventional materials namely palm kernel shell (PKS) and periwinkle shell (PW... more Performance of non-conventional materials namely palm kernel shell (PKS) and periwinkle shell (PWS) were investigated. Sieve analysis, aggregate impact value (AIV), aggregate crushing value (ACV), bitumen penetration, Marshall Stability, flash and fire point were carried out in accordance with American Standard for Materials and Testing (ASTM) and British Standard (BS) specifications. A total of thirty-six samples were prepared by partially replacing coarse aggregate with PKS and PWS at 0%, 10%, 20%, 30%, 40% and 50%. The AIV and ACV values of 35.85% and 11.49% were obtained for PWS, while 6.42% and 9.22% respectively were obtained for PKS; this is usable for wearing course. The 10% partial replacement with PWS has Marshall Stability value of 2.33kN; 10% and 20% partial replacement with PKS has Marshall Stability values of 3.0kN and 2.2kN respectively, while 10%, 20% and 30% partial replacement with combination of PWS and PKS has Marshall Stability values of 3.22kN, 2.41kN and 2.21kN respectively; thus satisfying the requirement for light traffic road. Also, 10% and 20% partial replacement with the combination of PWS and PKS gives a flow value of 8.9 mm and 8.5 mm which can be used for light traffic. Hence, 10% to 20% partial replacement of coarse aggregate with PWS and PKS can be used as alternative material in asphaltic concrete to reduce the cost of construction.
This paper evaluates the self-compactibility of flowing sand-concretes (FSC) mixtures, incorporat... more This paper evaluates the self-compactibility of flowing sand-concretes (FSC) mixtures, incorporated various dune sand and marble powder contents, by testing flowability (determined by slump flow and v-funnel tests), passing ability (determined by L-box test) and segregation (determined by the visual stability index). The compressive strength at 28 days was also determined. Results show that the slump flow of all FSC mixtures lie between 450 and 840 mm, thus satisfying flowability according the recommendations of AFGC, except for the mixture made with 150 kg/m3 of marble powder (with a slump flow of 450 mm). V-funnel flow time, T500 time and L-box ratio of all mixtures were about 1.7-3.8 s, 0.6-2.3 s and 0.5-0.93 respectively. These results indicate that FSC have a v-funnel time shorter than the range proposed by EFNARC recommendations (8-12 s). Despite lower v-funnel times, no visual stability loss has been observed for all studied mixtures (all mixtures have a visual segregation index of 0 and 1).
High cost of cement used as binder in the production of concrete has led to a search for alternat... more High cost of cement used as binder in the production of concrete has led to a search for alternative. Using a mix design ratio of 1:2:4 and water binder ratio of 0.63, concrete cubes were casted using varying ordinary Portland cement (OPC): palm kernel shell ash (PKSA) and ordinary Portland cement (OPC): coconut shell ash (CSA) ratios of 100:0, 90:10, 80:20, 70:30 , 60:40 and 50:50 respectively. This research reveal that partial replacement of cement with 20% PKSA and CSA in concrete gives an average optimum compressive strength of 15.4 N/mm2 and 17.26 N/mm2 respectively at 28 days. While, the optimum value of compressive strength obtained at 28 days is 20.58 N/mm2 at 10% replacement with CSA. The value obtained is suitable for both light weight and heavy weight concrete respectively. Thus, the research show that the use of PKSA and CSA as a partial replacement for cement in concrete, at lower volume of replacement, will enhance the reduction of cement usage in concretes, thereby reducing the production cost and the environmental pollution caused by the dumping of the agricultural waste.
Sand-bentonite (SB) mixtures have been used successfully for construction of hydraulic barriers w... more Sand-bentonite (SB) mixtures have been used successfully for construction of hydraulic barriers when clayey soils are not available. Compacted layers of SB mixtures have been proposed and used in a variety of geotechnical structures as engineered barriers for the enhancement of impervious landfill liners. In the practice we will try to get an economical mixture that satisfies the hydraulic and mechanical requirements.
The effects of the bentonite additions are reflected in lower water permeability, and acceptable shear strength. In order to get an adequate dune sand bentonite mixtures, an investigation relative to the hydraulic and mechanical behavior is carried out in this study for different mixtures. According to the results obtained, the adequate percentage of bentonite should be between 12% and 15 %, which result in a hydraulic conductivity less than 10E–6 cm/s, and good shear strength.
The earthquake transmits to the structure a large quantity of energy that causes damage to struct... more The earthquake transmits to the structure a large quantity of energy that causes damage to structures. The seismic isolation technique can absorb a large quantity of the seismic energy. The seismic isolation concept is a new technique in earthquake engineering, its principle is quite simple, and it consists to create a discontinuity between the foundation and the superstructure, so that seismic energy cannot be completely transmitted into the structure.
Therefore, this article includes a numerical application of the nonlinear static method, the capacity spectrum method (CSM), on two types of structures, fixed base structure and isolated base structure. The CSM is one of the methods used for the evaluation of seismic performance. Its principle consists in superimposing a curve which represents the capacity of the structure originated from a non-linear static analysis (Pushover), with a curve representing the solicitation brought by the earthquake. The intersection of these two curves represents the point performance, which evaluates the maximum displacement of the structure in the plastic domain.
Self-compacting concrete (SCC) offers several economical and technical benefits, the use of steel... more Self-compacting concrete (SCC) offers several economical and technical benefits, the use of steel fibers extends its possibilities. This study was performed to compare the properties of SCC and fiber reinforced self-compacting concrete (FRSCC) with high volume of mineral addition. Six mixtures were elaborated in this study. The content of the cementitious materials and the water/cementitious materials ratio were kept constant, 500 kg/m3 and 0.34 respectively.
The self-compacting mixtures have been prepared with a cement replacement of 30% by weight of marble powder. Two different types of steel fibers were used in combination with different lengths (50 mm and 30 mm), keeping the total fiber content constant at 60 kg/m3. Slump flow time and diameter, sieve stability, and L-Box were performed to assess the fresh properties of the SCC and FRSCC. Compressive strength, splitting tensile strength, flexural strength and ultrasonic pulse velocity were determined for the hardened properties. A marginal improvement in the ultimate strength was observed. The addition of steel fiber enhanced the ductility significantly and the results indicated that high-volume of marble powder can be used to produce FRSCC, even though there is some decrease in the compressive strength because of the fiber geometry which affects the properties of SCC mixtures not only in the fresh state but also in the hardened state.
Several buildings throughout the world are built with blocks of compressed and stabilized ground.... more Several buildings throughout the world are built with blocks of compressed and stabilized ground. These blocks do not commonly have the same thermal properties necessary for their use. If the incorporation of stabilizer in these blocks like lime or cement increases the mechanical properties, it is not the case for the thermophysical properties. In this paper, the evolution of the thermal properties of earth blocks according to the rates of stabilizer and their nature was discussed. The experimental method of “hot iron” was applied. Results indicate that thermal conductivity increases when percentages of cement and lime increase. However, it decreases when the rates of the sawdust increase. Moreover, thermal resistance decreases according to the percentages of lime and cement, and increases according to the percentages of the sawdust.
This work presents an experimental study on the mechanical behavior of structural concrete reinfo... more This work presents an experimental study on the mechanical behavior of structural concrete reinforced by carbon fiber reinforced polymer (CFRP). The main purpose of this study is to test the applicability of this method of reinforcement in the beams to improve the behavior of concrete: strength and ductility. An experimental characterization of mechanical behavior by tensile test by three point bending is achieved, namely, the reinforcement of the lower part of the beam (15x15x75) cm3 with composite material, Based on the ANSYS simulation, a model was developed to validate the different results obtained experimentally. The experimental results show that the reinforced concrete offered a great improvement in strength and ductility; in effect an influence directly on the failure mode is observed and then read by the value of strength and ultimate deformation. The tensile bending of beams reinforced by CFRP is more than 295% in comparison with that of non-reinforced beams. The gain maximum of ductility is 247%. The experimental results have been compared with the theoretical models, a good correlation was obtained.
This work aims to investigate the strength development of ultra-high performance fiber reinforced... more This work aims to investigate the strength development of ultra-high performance fiber reinforced concrete (UHPFRC) containing ground dune sand (GDS) and ground brick waste (GWB) as a substitutions of cement and dune sand (DS) as an aggregate. The variables are the nature of addition (GDS and GWB) in the binder and the heat curing at different temperatures (20°C and 60°C) at 7 days of curing. Two temperatures 20°C and 60 °C were applied to samples with intermediate levels for 8 hours in total. In this study, two types of cements (CEMI and CEMII) were used to prepare UHPFRC. The GWB was replaced by GDS at levels of 10, 20 and 30% by weight. The results show that the obtained concretes develop a high mechanical performance with a suitable heat treatment according to the cement type and the used fiber. The compressive strength at 7 days of UHPFRC has increased with heat curing (at 60 °C) compared to that obtained at 28 days and measured at 20 °C. Results show also that values of compressive strength of concrete containing DS are close to those obtained by the control concrete. This study has showed that the dune sand can be used in UHPRC, and that the substitution of the GWB by GDS can provide concretes with acceptable mechanical performance.
Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to... more Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and some different other national design codes, the structural integrity of civil engineering structures should be ensured through appropriate measures but, in most cases, no precise practical guidelines on how to achieve this goal are provided.
At Liège University, the robustness of building frames is investigated with the final objective to propose design requirements to mitigate the risk of progressive collapse considering the conventional scenario “loss of a column” further to an unspecified event. In particular, a complete analytical procedure has been developed for the verification of the robustness of steel or composite plane frames. For sake of simplicity, these first works have been based on the assumption that the dynamic effects linked to the column loss were limited and could therefore be neglected. More recently, complementary works have been carried out with the objective to address the dynamic effects. Besides that, the extension of the static procedure to actual 3D frames is under investigation in Liège. The present paper gives a global overview of the ongoing researches in the field of robustness at Liège University; in particular, the global strategy to derive design requirements is detailed.
On the basis of the principle that a concrete is composed of a liquid phase (paste) and a solid p... more On the basis of the principle that a concrete is composed of a liquid phase (paste) and a solid phase (aggregates with fixed gravel/sand ratio), the concrete self-compacting properties come necessarily from those of the paste. The present work is the continuity of a first phase of the testing already conducted, which resulted in obtaining an optimal self-compacting cement paste composition. This paste will be used to prepare a self-compacting concrete (SCC), while passing from the scale of the cement paste to that of the concrete, by injecting wet aggregate to the self-compacting paste. The excess paste theory was used to determine the thickness of the paste coating each aggregate with a given diameter of constituting granular skeleton, then generalized for the determination of the quantity of total paste allowing the flow of the concrete by decreasing frictions between the grains of its granular skeleton. This approach was also experimentally validated. The influence of the granular distribution was minimized by the use of the approach based on the determination of the average diameter of the aggregates. This required the determination of a homothetic factor “k” similar for all concretes with different aggregate grading. Formulation of a self-compacting concrete passes initially by the determination of a sufficient quantity of paste allowing its flow without frictions between its aggregates and to balance the mixture by the quantity of water retained by the aggregates. The self-compacting concrete characteristics would come from those of the cement paste which composes it.
Satisfying the ever-growing demand of concrete aggregates poses a problem in many parts of the wo... more Satisfying the ever-growing demand of concrete aggregates poses a problem in many parts of the world due to shortage of natural sand. Moreover, to conserve natural resources and protect civil engineering infrastructures, there is a need to find alternative materials. Crushed stone sand has been identified as a potential substitute material for natural sand in making good quality concrete. The main objective of the present investigation is to determine an adequate mix design method and evaluate engineering properties of crushed limestone sand concrete mixtures in both the fresh and hardened sates. More than thirty concrete mixtures were examined. The results indicate that water demand and cement paste content in crushed sand concrete are generally higher than that used in similar conventional concrete. Good mechanical properties were obtained for concrete using crushed limestone sand as fine aggregates with a superplasticizer. However, a higher than normally used dosage of superplasticizer is required in these concrete mixtures and the optimum dosage of the superplasticizer needs to be determined for each cement and sand content.
The aim of the present paper is to provide a mixture design modelling to evaluate the effect of d... more The aim of the present paper is to provide a mixture design modelling to evaluate the effect of different sand types on fresh properties of self-compacting concrete (SCC). A statistical approach was used to highlight the effect of river sand (RS), crushed sand (CS) and dune sand (DS) as proportions in binary and ternary systems in SCC composition. The responses of the derived statistical models are sand packing density (SPD), T500 and J-ring. The resulting mathematical models are used to illustrate the variation of different responses in ternary contours plots with respect to the proportions of RS, CS and DS. This offers flexibility to optimize RS, CS and DS blends with tailor-made of a given property that suit a particular recommendations. Results indicate that SPD of RS can be enhanced by a 40% of CS and 30% of DS proportions. Moreover, it is shown that flowability, measured by J-ring, can be improved by the increase of CS and DS in RS-CS and RS-DS binary systems. Results also indicate that passing ability measured with T500 decreased with the increase of CS proportion and increased with the increase of DS proportion in binary and ternary systems.
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Papers by Journal of Building Materials and Structures (JBMS)
The effects of the bentonite additions are reflected in lower water permeability, and acceptable shear strength. In order to get an adequate dune sand bentonite mixtures, an investigation relative to the hydraulic and mechanical behavior is carried out in this study for different mixtures. According to the results obtained, the adequate percentage of bentonite should be between 12% and 15 %, which result in a hydraulic conductivity less than 10E–6 cm/s, and good shear strength.
Therefore, this article includes a numerical application of the nonlinear static method, the capacity spectrum method (CSM), on two types of structures, fixed base structure and isolated base structure. The CSM is one of the methods used for the evaluation of seismic performance. Its principle consists in superimposing a curve which represents the capacity of the structure originated from a non-linear static analysis (Pushover), with a curve representing the solicitation brought by the earthquake. The intersection of these two curves represents the point performance, which evaluates the maximum displacement of the structure in the plastic domain.
The self-compacting mixtures have been prepared with a cement replacement of 30% by weight of marble powder. Two different types of steel fibers were used in combination with different lengths (50 mm and 30 mm), keeping the total fiber content constant at 60 kg/m3. Slump flow time and diameter, sieve stability, and L-Box were performed to assess the fresh properties of the SCC and FRSCC. Compressive strength, splitting tensile strength, flexural strength and ultrasonic pulse velocity were determined for the hardened properties. A marginal improvement in the ultimate strength was observed. The addition of steel fiber enhanced the ductility significantly and the results indicated that high-volume of marble powder can be used to produce FRSCC, even though there is some decrease in the compressive strength because of the fiber geometry which affects the properties of SCC mixtures not only in the fresh state but also in the hardened state.
At Liège University, the robustness of building frames is investigated with the final objective to propose design requirements to mitigate the risk of progressive collapse considering the conventional scenario “loss of a column” further to an unspecified event. In particular, a complete analytical procedure has been developed for the verification of the robustness of steel or composite plane frames. For sake of simplicity, these first works have been based on the assumption that the dynamic effects linked to the column loss were limited and could therefore be neglected. More recently, complementary works have been carried out with the objective to address the dynamic effects. Besides that, the extension of the static procedure to actual 3D frames is under investigation in Liège. The present paper gives a global overview of the ongoing researches in the field of robustness at Liège University; in particular, the global strategy to derive design requirements is detailed.
The effects of the bentonite additions are reflected in lower water permeability, and acceptable shear strength. In order to get an adequate dune sand bentonite mixtures, an investigation relative to the hydraulic and mechanical behavior is carried out in this study for different mixtures. According to the results obtained, the adequate percentage of bentonite should be between 12% and 15 %, which result in a hydraulic conductivity less than 10E–6 cm/s, and good shear strength.
Therefore, this article includes a numerical application of the nonlinear static method, the capacity spectrum method (CSM), on two types of structures, fixed base structure and isolated base structure. The CSM is one of the methods used for the evaluation of seismic performance. Its principle consists in superimposing a curve which represents the capacity of the structure originated from a non-linear static analysis (Pushover), with a curve representing the solicitation brought by the earthquake. The intersection of these two curves represents the point performance, which evaluates the maximum displacement of the structure in the plastic domain.
The self-compacting mixtures have been prepared with a cement replacement of 30% by weight of marble powder. Two different types of steel fibers were used in combination with different lengths (50 mm and 30 mm), keeping the total fiber content constant at 60 kg/m3. Slump flow time and diameter, sieve stability, and L-Box were performed to assess the fresh properties of the SCC and FRSCC. Compressive strength, splitting tensile strength, flexural strength and ultrasonic pulse velocity were determined for the hardened properties. A marginal improvement in the ultimate strength was observed. The addition of steel fiber enhanced the ductility significantly and the results indicated that high-volume of marble powder can be used to produce FRSCC, even though there is some decrease in the compressive strength because of the fiber geometry which affects the properties of SCC mixtures not only in the fresh state but also in the hardened state.
At Liège University, the robustness of building frames is investigated with the final objective to propose design requirements to mitigate the risk of progressive collapse considering the conventional scenario “loss of a column” further to an unspecified event. In particular, a complete analytical procedure has been developed for the verification of the robustness of steel or composite plane frames. For sake of simplicity, these first works have been based on the assumption that the dynamic effects linked to the column loss were limited and could therefore be neglected. More recently, complementary works have been carried out with the objective to address the dynamic effects. Besides that, the extension of the static procedure to actual 3D frames is under investigation in Liège. The present paper gives a global overview of the ongoing researches in the field of robustness at Liège University; in particular, the global strategy to derive design requirements is detailed.