Search results for: cover concrete
2571 Mode II Fracture Toughness of Hybrid Fiber Reinforced Concrete
Authors: H. S. S Abou El-Mal, A. S. Sherbini, H. E. M. Sallam
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Mode II fracture toughness (KIIc) of fiber reinforced concrete has been widely investigated under various patterns of testing geometries. The effect of fiber type, concrete matrix properties, and testing mechanisms were extensively studied. The area of hybrid fiber addition shows a lake of reported research data. In this paper an experimental investigation of hybrid fiber embedded in high strength concrete matrix is reported. Three different types of fibers; namely steel (S), glass (G), and polypropylene (PP) fibers were mixed together in four hybridization patterns, (S/G), (S/PP), (G/PP), (S/G/PP) with constant cumulative volume fraction (Vf) of 1.5%. The concrete matrix properties were kept the same for all hybrid fiber reinforced concrete patterns. In an attempt to estimate a fairly accepted value of fracture toughness KIIc, four testing geometries and loading types are employed in this investigation. Four point shear, Brazilian notched disc, double notched cube, and double edge notched specimens are investigated in a trial to avoid the limitations and sensitivity of each test regarding geometry, size effect, constraint condition, and the crack length to specimen width ratio a/w. The addition of all hybridization patterns of fiber reduced the compressive strength and increased mode II fracture toughness in pure mode II tests. Mode II fracture toughness of concrete KIIc decreased with the increment of a/w ratio for all concretes and test geometries. Mode II fracture toughness KIIc is found to be sensitive to the hybridization patterns of fiber. The (S/PP) hybridization pattern showed higher values than all other patterns, while the (S/G/PP) showed insignificant enhancement on mode II fracture toughness (KIIc). Four point shear (4PS) test set up reflects the most reliable values of mode II fracture toughness KIIc of concrete. Mode II fracture toughness KIIc of concrete couldn’t be assumed as a real material property.Keywords: fiber reinforced concrete, Hybrid fiber, Mode II fracture toughness, testing geometry
Procedia PDF Downloads 3222570 The Effect of Urmia-Lake Water on Tensional Strength Concrete with Various Admixtures
Authors: Hadi Barghlame, M. A. Lotfollahi-Yaghin, Mehdi Mohammad Rezaei
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In this paper, the effect of admixtures on the tensional strength of concrete in Urmia-lake water have been investigated. We made different types of concretes with the ratio of w/c and replaced different percentages of micro-silica, air-entraining, super plasticizer, corrosion-inhibiting, and caulk with two types of cement I and II as well as investigating in both ordinary water and Urmia-lake water. The tensional strength was investigated on these samples.Keywords: Urmia-lake water, tensional strength, concrete, admixtures
Procedia PDF Downloads 3462569 Reformulation of Theory of Critical Distances to Predict the Strength of Notched Plain Concrete Beams under Quasi Static Loading
Authors: Radhika V., J. M. Chandra Kishen
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The theory of critical distances (TCD), due to its appealing characteristics, has been successfully used in the past to predict the strength of brittle as well as ductile materials, weakened by the presence of stress risers under both static and fatigue loading. By utilising most of the TCD's unique features, this paper summarises an attempt for a reformulation of the point method of the TCD to predict the strength of notched plain concrete beams under mode I quasi-static loading. A zone of micro cracks, which is responsible for the non-linearity of concrete, is taken into account considering the concept of an effective elastic crack. An attempt is also made to correlate the value of the material characteristic length required for the application of TCD with the maximum aggregate size in the concrete mix, eliminating the need for any extensive experimentation prior to the application of TCD. The devised reformulation and the proposed power law based relationship is found to yield satisfactory predictions for static strength of notched plain concrete beams, with geometric dimensions of the beam, tensile strength, and maximum aggregate size of the concrete mix being the only needed input parameters.Keywords: characteristic length, effective elastic crack, inherent material strength, modeI loading, theory of critical distances
Procedia PDF Downloads 942568 Properties of Ground Granulated Blast Furnace Slag Based Geopolymer Concrete
Authors: Niragi Dave, Ruchika Lalit
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Concrete is one of the most widely used materials across the globe mostly second to water and generating high carbon dioxide emission during its whole manufacturing due to the presence of cement as an ingredient. Therefore it is necessary to find an alternative material to the Portland cement. This study focused on the use of Ground Granulated Blast Furnace Slag as geopolymer binder. Geopolymer concrete can be an alternative material which is produced by the chemical reaction of inorganic molecules. On the other hand, waste generating from power plants and other industries like iron and steel industries can be effectively used which has disposal problems. Therefore in this study geopolymer concrete is manufactured by 100% replacement of cement content by ground granulated blast furnace slag and a combination of sodium silicate and sodium hydroxide is used as an alkaline solution. The results have shown that the compressive strengths increased with increasing curing time and type of alkali activators. Naphthalene sulfonate-based superplasticizer performed better than other superplasticizers. All the specimens have been cast at ambient temperature.Keywords: alkali activators, concrete, geopolymer, ground granulated blast furnace slag
Procedia PDF Downloads 3162567 Influence of Gum Acacia Karroo on Some Mechanical Properties of Cement Mortars and Concrete
Authors: Mbugua R. N., Salim R. W., Ndambuki J. M.
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Natural admixtures provide concrete with enhanced properties but their processing end up making them very expensive resulting in increase to cost of concrete. In this study the effect of Gum from Acacia Karroo (GAK) as set-retarding admixture in cement pastes was studied. The possibility of using GAK as water reducing admixture both in cement mortar concrete was also investigated. Cement pastes with different dosages of GAK were prepared to measure the setting time using different dosages. Compressive strength of cement mortars with 0.7, 0.8 and 0.9% weight of cement and w/c ratio of 0.5 were compared to those with water cement (w/c) ratio of 0.44 but same dosage of GAK. Concrete samples were prepared using higher dosages of GAK (1, 2 and 3\% wt of cement) and a water bidder (w/b) of 0.61 were compared to those with the same GAK dosage but with reduced w/b ratio. There was increase in compressive strength of 9.3% at 28 days for cement mortar samples with 0.9% dosage of GAK and reduced w/c ratio.Keywords: compressive strength, Gum Acacia Karroo, retarding admixture, setting time, water-reducing admixture
Procedia PDF Downloads 3052566 Code Evaluation on Web-Shear Capacity of Presstressed Hollow-Core Slabs
Authors: Min-Kook Park, Deuck Hang Lee, Hyun Mo Yang, Jae Hyun Kim, Kang Su Kim
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Prestressed hollow-core slabs (HCS) are structurally optimized precast units with light-weight hollowed-sections and very economical due to the mass production by a unique production method. They have been thus widely used in the precast concrete constructions in many countries all around the world. It is, however, difficult to provide shear reinforcement in HCS units produced by the extrusion method, and thus all the shear forces should be resisted solely by concrete webs in the HCS units. This means that, for the HCS units, it is very important to estimate the contribution of web concrete to the shear resistance accurately. In design codes, however, the shear strengths for HCS units are estimated by the same equations that are used for typical prestressed concrete members, which were determined from the calibrations to experimental results of conventional prestressed concrete members other than HCS units. In this study, therefore, shear test results of HCS members with a wide range of influential variables were collected, and the shear strength equations in design codes were thoroughly examined by comparing to the experimental results in the shear database of HCS members. Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning(NRF-2016R1A2B2010277).Keywords: hollow-core, web-shear, precast concrete, prestress, capacity
Procedia PDF Downloads 5012565 Experimental Studies on the Corrosion Effects of the Concrete Made with Tannery Effluent
Authors: K. Nirmalkumar
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An acute water scarcity is prevailing in the dry season in and around Perundurai (Erode district, Tamil Nadu, India) where there are more number of tannery units. Hence an attempt was made to use the effluent from the tannery industry for construction purpose. The mechanical properties such as compressive strength, tensile strength, flexural strength and the special properties such as chloride attack, sulphate attack and chemical attack were studied by casting various concrete specimens in form of cube, cylinders and beams, etc. It was observed that the concrete had some reduction in strength while subjected to chloride attack, sulphate attack and chemical attack. So admixtures were selected and optimized in suitable proportion to counter act the adverse effects and the results were found to be satisfactory. In this research study the corrosion results of specimens prepared by using treated and untreated tannery effluent were compared with the concrete specimens prepared by using potable water. It was observed that by the addition of admixtures, the adverse effects due to the usage of the treated and untreated tannery effluent are counteracted.Keywords: corrosion, calcium nitrite, concrete, fly ash
Procedia PDF Downloads 2642564 Anticipation of Bending Reinforcement Based on Iranian Concrete Code Using Meta-Heuristic Tools
Authors: Seyed Sadegh Naseralavi, Najmeh Bemani
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In this paper, different concrete codes including America, New Zealand, Mexico, Italy, India, Canada, Hong Kong, Euro Code and Britain are compared with the Iranian concrete design code. First, by using Adaptive Neuro Fuzzy Inference System (ANFIS), the codes having the most correlation with the Iranian ninth issue of the national regulation are determined. Consequently, two anticipated methods are used for comparing the codes: Artificial Neural Network (ANN) and Multi-variable regression. The results show that ANN performs better. Predicting is done by using only tensile steel ratio and with ignoring the compression steel ratio.Keywords: adaptive neuro fuzzy inference system, anticipate method, artificial neural network, concrete design code, multi-variable regression
Procedia PDF Downloads 2762563 Measurement of the Dynamic Modulus of Elasticity of Cylindrical Concrete Specimens Used for the Cyclic Indirect Tensile Test
Authors: Paul G. Bolz, Paul G. Lindner, Frohmut Wellner, Christian Schulze, Joern Huebelt
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Concrete, as a result of its use as a construction material, is not only subject to static loads but is also exposed to variables, time-variant, and oscillating stresses. In order to ensure the suitability of construction materials for resisting these cyclic stresses, different test methods are used for the systematic fatiguing of specimens, like the cyclic indirect tensile test. A procedure is presented that allows the estimation of the degradation of cylindrical concrete specimens during the cyclic indirect tensile test by measuring the dynamic modulus of elasticity in different states of the specimens’ fatigue process. Two methods are used in addition to the cyclic indirect tensile test in order to examine the dynamic modulus of elasticity of cylindrical concrete specimens. One of the methods is based on the analysis of eigenfrequencies, whilst the other one uses ultrasonic pulse measurements to estimate the material properties. A comparison between the dynamic moduli obtained using the three methods that operate in different frequency ranges shows good agreement. The concrete specimens’ fatigue process can therefore be monitored effectively and reliably.Keywords: concrete, cyclic indirect tensile test, degradation, dynamic modulus of elasticity, eigenfrequency, fatigue, natural frequency, ultrasonic, ultrasound, Young’s modulus
Procedia PDF Downloads 1692562 Modelling the Effects of External Factors Affecting Concrete Carbonation
Authors: Abhishek Mangal, Kunal Tongaria, S. Mandal, Devendra Mohan
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Carbonation of reinforced concrete structures has emerged as one of the major challenges for Civil engineers across the world. With increasing emissions from various activities, carbon dioxide concentration in the atmosphere has been eve rising, enhancing its penetration in porous concrete, reaching steel bars and ultimately leading to premature failure. Several literatures have been published dealing with the various interdependent variables related to carbonation. However, with innumerable variability a generalization of these data proves to be a troublesome task. This paper looks into this carbonation anomaly in concrete structures caused by various external variables such as relative humidity, concentration of CO2, curing period and ambient temperature. Significant discussions and comparisons have been presented on the basis of various studies conducted with an aim to predict the depth of carbonation as a function of these multidimensional parameters using various numerical and statistical modelling techniques.Keywords: carbonation, curing, exposure conditions, relative humidity
Procedia PDF Downloads 2492561 Examples of RC Design with Eurocode2
Authors: Carla Ferreira, Helena Barros
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The paper termed “Design of reinforced concrete with Eurocode 2” presents the theory regarding the design of reinforced concrete sections and the development of the tables and abacuses to verify the concrete section to the ultimate limit and service limit states. This paper is a complement of it, showing how to use the previous tools. Different numerical results are shown, proving the capability of the methodology. When a section of a beam is already chosen, the computer program presents the reinforcing steel in many locations along the structure, and it is the engineer´s task to choose the layout available for the construction, considering the maximum regular kind of reinforcing bars. There are many computer programs available for this task, but the interest of the present kind of tools is the fast and easy way of making the design and choose the optimal solution. Another application of these design tools is in the definition of the section dimensions, in a way that when stresses are evaluated, the final design is acceptable. In the design offices, these are considered by the engineers a very quick and useful way of designing reinforced concrete sections, employing variable strength concrete and higher steel classes. Examples of nonlinear analyses and redistribution of the bending moment will be considered, according to the Eurocode 2 recommendations, for sections under bending moment and axial forces. Examples of the evaluation of the service limit state will be presented.Keywords: design examples, eurocode 2, reinforced concrete, section design
Procedia PDF Downloads 622560 Durability and Early-Age Behavior of Sprayed Concrete with an Expansion Admixture
Authors: Kyong-Ku Yun, Kyeo-Re Lee, Kyong Namkung, Seung-Yeon Han, Pan-Gil Choi
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Sprayed concrete is a way to spray a concrete using a machinery with high air pressure. There are insufficient studies on the durability and early-age behavior of sprayed concrete using high quality expansion agent. A series of an experiment were executed with 5 varying expansion agent replacement rates, while all the other conditions were kept constant, including cement binder content and water-cement ratio. The tests includes early-age shrinkage test, rapid chloride permeability test, and image analysis of air void structure. The early-age expansion test with the variation of expansion agent show that the expansion strain increases as the ratio of expansion agent increases. The rapid chloride permeability test shows that it decrease as the expansion agent increase. Therefore, expansion agent affects into the rapid chloride permeability in a better way. As expansion agent content increased, spacing factor slightly decreased while specific surface kept relatively stable. As a results, the optimum ratio of expansion agent would be selected between 7 % and 11%.Keywords: sprayed concrete, durability, early-age behavior, expansion admixture
Procedia PDF Downloads 4982559 Design, Construction and Evaluation of Ultra-High-Performance Concrete (UHPC) Bridge Deck Overlays
Authors: Jordy Padilla
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The New Jersey Department of Transportation (NJDOT) initiated a research project to install and evaluate Ultra-High-Performance Concrete (UHPC) as an overlay on existing bridges. The project aims to implement UHPC overlays in NJDOT bridge deck strategies for preservation and repair. During design, four bridges were selected for construction. The construction involved the removal of the existing bridge asphalt overlays, partially removing the existing concrete deck surface, and resurfacing the deck with a UHPC overlay. In some cases, a new asphalt riding surface was placed. Additionally, existing headers were replaced with full-depth UHPC. The UHPC overlay is monitored through coring and Non-destructive testing (NDT) to ensure that the interfacial bond is intact and that the desired conditions are maintained. The NDT results show no evidence that the bond between the new UHPC overlay and the existing concrete deck is compromised. Bond strength test data demonstrates that, in general, the desired bond was achieved between UHPC and the substrate concrete, although the results were lower than anticipated. Chloride content is also within expectations except for one anomaly. The baseline testing was successful, and no significant defects were encountered.Keywords: ultra-high performance concrete, rehabilitation, non-destructive testing
Procedia PDF Downloads 772558 Embedment Design Concept of Signature Tower in Chennai
Authors: M. Gobinath, S. Balaji
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Assumptions in model inputs: Grade of concrete=40 N/mm2 (for slab), Grade of concrete=40 N/mm2 (for shear wall), Grade of Structural steel (plate girder)=350 N/mm2 (yield strength), Ultimate strength of structural steel=490 N/mm2, Grade of rebar=500 N/mm2 (yield strength), Applied Load=1716 kN (un-factored). Following assumptions are made for the mathematical modelling of RCC with steel embedment: (1) The bond between the structural steel and concrete is neglected. (2) The stiffener is provided with shear studs to transfer the shear force. Hence nodal connectivity is established between solid nodes (concrete) and shell elements (stiffener) at those locations. (3) As the end reinforcements transfer either tension/compression, it is modeled as line element and connected to solid nodes. (4) In order to capture the bearing of bottom flange on to the concrete, the line element of plan size of solid equal to the cross section of line elements is connected between solid and shell elements below for bottom flange and above for top flange. (5) As the concrete cannot resist tension at the interface (i.e., between structural steel and RCC), the tensile stiffness is assigned as zero and only compressive stiffness is enabled to take. Hence, non-linear static analysis option is invoked.Keywords: structure, construction, signature tower, embedment design concept
Procedia PDF Downloads 2942557 Study of Corrosion in Structures due to Chloride Infiltration
Authors: Sukrit Ghorai, Akku Aby Mathews
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Corrosion in reinforcing steel is the leading cause for deterioration in concrete structures. It is an electrochemical process which leads to volumetric change in concrete and causes cracking, delamination and spalling. The objective of the study is to provide a rational method to estimate the probable chloride concentration at the reinforcement level for a known surface chloride concentration. The paper derives the formulation of design charts to aid engineers for quick calculation of the chloride concentration. Furthermore, the paper focuses on comparison of durability design against corrosion with American, European and Indian design standards.Keywords: chloride infiltration, concrete, corrosion, design charts
Procedia PDF Downloads 4052556 Evaluation of Water Quality on the Strength of Simple Concrete: Case Study of Wells in Jipijapa, Manabí, Ecuador
Authors: Julio Cesar Pino Tarragó, Dunia Lisbet Domínguez Gálvez, Luis Alfonso Moreno Ponce, Jhony Julio Regalado Jalca
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This study examines the impact of three distinct types of water on the compressive strength of plain concrete, focusing on samples from wells in Jipijapa, Manabí, Ecuador: Joa water, characterized by high sulfur content; Chade 1 water, with low sulfur content; and Chade 2 water, which is highly brackish. Compressive strength tests were conducted at 7, 14, and 28 days to assess the influence of these water types on the structural integrity of the concrete. The results indicate that both brackish and sulfur-rich water significantly reduces concrete strength, while Chade 1 water, though initially enhancing strength, displays variability in long-term performance. These outcomes underscore the importance of optimizing construction practices in regions like Jipijapa, where potable water is scarce, by exploring sustainable alternatives for using non-potable water, thereby conserving limited water resources.Keywords: compressive strength, plain concrete, sulfur water, brackish water, water quality
Procedia PDF Downloads 132555 Shear Behavior of Ultra High Strength Concrete Beams
Authors: Ghada Diaa, Enas A. Khattab
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Ultra High Strength Concrete (UHSC) is a new advanced concrete that is being transferred from laboratory researches to practicable applications. In addition to its excellent durability properties, UHSC has high compressive and tensile strengths, and high modulus of elasticity. Despite of this low degree of hydration, ultra high strength values can be achieved by controlling the mixture proportions. In this research, an experimental program was carried out to investigate the shear behavior of ultra high strength concrete beams. A total of nine beams were tested to determine the effect of different parameters on the shear behavior of UHSC beams. The parameters include concrete strength, steel fiber volume, shear span to depth ratio, and web reinforcement ratio. The results demonstrated that nominal shear stress at cracking load and at ultimate load increased with the increase of concrete strength or the decrease in shear span-depth ratio. Using steel fibers or shear reinforcement increases the ultimate shear strength and makes the shear behavior more ductile. In this study, a simplified analytical model to calculate the shear strength of UHSC beams is introduced. Shear strength estimated according to the proposed method in this research is in good agreement with the experimental results.Keywords: ultra high strength, shear strength, diagonal, cracking, steel fibers
Procedia PDF Downloads 6112554 Structural Behavior of Laterally Loaded Precast Foamed Concrete Sandwich Panel
Authors: Y. H. Mugahed Amran, Raizal S. M. Rashid, Farzad Hejazi, Nor Azizi Safiee, A. A. Abang Ali
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Experimental and analytical studies were carried out to investigate the structural behavior of precast foamed concrete sandwich panels (PFCSP) of total number (6) as one-way action slab tested under lateral load. The details of the test setup and procedures were illustrated. The results obtained from the experimental tests were discussed which include the observation of cracking patterns and influence of aspect ratio (L/b). Analytical study of finite element analysis was implemented and degree of composite action of the test panels was also examined in both experimental and analytical studies. Result shows that crack patterns appeared in only one-direction, similar to reports on solid slabs, particularly when both concrete wythes act in a composite manner. Foamed concrete was briefly reviewed and experimental results were compared with the finite element analyses data which gives a reasonable degree of accuracy. Therefore, based on the results obtained, PFCSP slab can be used as an alternative to conventional flooring system.Keywords: aspect ratio (L/b), finite element analyses (FEA), foamed concrete (FC), precast foamed concrete sandwich panel (PFCSP), ultimate flexural strength capacity
Procedia PDF Downloads 3102553 Selected Technological Factors Influencing the Modulus of Elasticity of Concrete
Authors: Klara Krizova, Rudolf Hela
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The topic of the article focuses on the evaluation of selected technological factors and their influence on resulting elasticity modulus of concrete. A series of various factors enter into the manufacturing process which, more or less, influences the elasticity modulus. This paper presents the results of concrete in which the influence of water coefficient and the size of maximum fraction of the aggregate on the static elasticity modulus were monitored. Part of selected results of the long-term programme was discussed in which a wide scope of various variants of proposals for the composition of concretes was evaluated.Keywords: mix design, water-cement ratio, aggregate, modulus of elasticity
Procedia PDF Downloads 3912552 Advanced Concrete Crack Detection Using Light-Weight MobileNetV2 Neural Network
Authors: Li Hui, Riyadh Hindi
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Concrete structures frequently suffer from crack formation, a critical issue that can significantly reduce their lifespan by allowing damaging agents to enter. Traditional methods of crack detection depend on manual visual inspections, which heavily relies on the experience and expertise of inspectors using tools. In this study, a more efficient, computer vision-based approach is introduced by using the lightweight MobileNetV2 neural network. A dataset of 40,000 images was used to develop a specialized crack evaluation algorithm. The analysis indicates that MobileNetV2 matches the accuracy of traditional CNN methods but is more efficient due to its smaller size, making it well-suited for mobile device applications. The effectiveness and reliability of this new method were validated through experimental testing, highlighting its potential as an automated solution for crack detection in concrete structures.Keywords: Concrete crack, computer vision, deep learning, MobileNetV2 neural network
Procedia PDF Downloads 642551 Study of Ladle Furnace Slag as Mineral Filler in Asphalt Concrete with Electric Arc Furnace Slag
Authors: W. J. Wang, D. F. Lin, L. Y. Chen, K. Y. Liu
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In this study, the ladle furnace slag was used as a mineral filler in asphalt concrete with electric arc furnace slag (EAF asphalt concrete) to investigate the effect on the engineering and thermal properties of asphalt cement mastics and EAF asphalt concrete, the lime was used as a comparison for mineral filler, and the usage percentage of mineral filler was set at 2%, 4%, 6%, and 8%. First of all, the engineering properties of the ladle furnace slag and lime were compared, and then the mineral filler was mixed with bitumen to form the asphalt cement mastics in order to analyze the influence of the ladle furnace slag on the properties of asphalt cement mastics, and lastly, the mineral filler was used in the EAF asphalt concrete to analyze its feasibility of using ladle furnace slag as a mineral filler. The study result shows that the ladle furnace slag and the lime have no obvious difference in their physical properties, and from the energy dispersive spectrometer (EDS) test results, we know that the lime and the ladle furnace slag have similar elemental composition, but the Ca found in the ladle furnace slag belongs to CaO, and the lime belongs to CaCO3, therefore the ladle furnace slag has the property of expansion. According to the test results, the viscosity of asphalt cement mastics will increase with the increase in the use of mineral filler. Since the ladle furnace slag has more CaO content, the viscosity of the asphalt cement mastics with ladle furnace slag will increase more than using lime as mineral filler in the asphalt cement mastics, and the use of ladle furnace slag only needs to be 2% in order to achieve the effect of anti-peeling which is 6% for lime. From the related test results of EAF asphalt concrete, it is known that the maximum stability value can be obtained when the use of mineral filler is about 5%. When the ladle furnace slag is used as the mineral filler, it can improve the stiffness, indirect tension strength, spalling resistance, and thermal insulation of EAF asphalt concrete, which also indicates that using the ladle furnace slag as the mineral filler of bitumen can help to improve the durability of the asphalt pavement.Keywords: ladle furnace slag, mineral filler, asphalt cement mastics, EAF asphalt concrete
Procedia PDF Downloads 742550 A Lightweight Interlock Block from Foamed Concrete with Construction and Agriculture Waste in Malaysia
Authors: Nor Azian Binti Aziz, Muhammad Afiq Bin Tambichik, Zamri Bin Hashim
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The rapid development of the construction industry has contributed to increased construction waste, with concrete waste being among the most abundant. This waste is generated from ready-mix batching plants after the concrete cube testing process is completed and disposed of in landfills, leading to increased solid waste management costs. This study aims to evaluate the engineering characteristics of foamed concrete with waste mixtures construction and agricultural waste to determine the usability of recycled materials in the construction of non-load-bearing walls. This study involves the collection of construction wastes, such as recycled aggregates (RCA) obtained from the remains of finished concrete cubes, which are then tested in the laboratory. Additionally, agricultural waste, such as rice husk ash, is mixed into foamed concrete interlock blocks to enhance their strength. The optimal density of foamed concrete for this study was determined by mixing mortar and foam-backed agents to achieve the minimum targeted compressive strength required for non-load-bearing walls. The tests conducted in this study involved two phases. In Phase 1, elemental analysis using an X-ray fluorescence spectrometer (XRF) was conducted on the materials used in the production of interlock blocks such as sand, recycled aggregate/recycled concrete aggregate (RCA), and husk ash paddy/rice husk ash (RHA), Phase 2 involved physical and thermal tests, such as compressive strength test, heat conductivity test, and fire resistance test, on foamed concrete mixtures. The results showed that foamed concrete can produce lightweight interlock blocks. X-ray fluorescence spectrometry plays a crucial role in the characterization, quality control, and optimization of foamed concrete mixes containing construction and agriculture waste. The unique composition mixer of foamed concrete and the resulting chemical and physical properties, as well as the nature of replacement (either as cement or fine aggregate replacement), the waste contributes differently to the performance of foamed concrete. Interlocking blocks made from foamed concrete can be advantageous due to their reduced weight, which makes them easier to handle and transport compared to traditional concrete blocks. Additionally, foamed concrete typically offers good thermal and acoustic insulation properties, making it suitable for a variety of building projects. Using foamed concrete to produce lightweight interlock blocks could contribute to more efficient and sustainable construction practices. Additionally, RCA derived from concrete cube waste can serve as a substitute for sand in producing lightweight interlock blocks.Keywords: construction waste, recycled aggregates (RCA), sustainable concrete, structure material
Procedia PDF Downloads 492549 Investigating the Properties of Asphalt Concrete Containing Recycled Fillers
Authors: Hasan Taherkhani
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Increasingly accumulation of the solid waste materials has become a major environmental problem of communities. In addition to the protection of environment, the recycling and reusing of the waste materials are financially beneficial. Waste materials can be used in highway construction. This study aimed to investigate the applicability of recycled concrete, asphalt and steel slag powder, as a replacement of the primary mineral filler in asphalt concrete has been investigated. The primary natural siliceous aggregate filler, as control, has been replaced with the secondary recycled concrete, asphalt and steel slag powders, and some engineering properties of the mixtures have been evaluated. Marshal Stability, flow, indirect tensile strength, moisture damage, static creep and volumetric properties of the mixtures have been evaluated. The results show that, the Marshal Stability of the mixtures containing recycled powders is higher than that of the control mixture. The flow of the mixtures containing recycled steel slag is lower, and that of the mixtures containing recycled asphalt and cement concrete powder is found to be higher than that of the control mixture. It is also found that the resistance against moisture damage and permanent deformation of the mixture can be improved by replacing the natural filler with the recycled powders. The volumetric properties of the mixtures are not significantly influenced by replacing the natural filler with the recycled powders.Keywords: filler, steel slag, recycled concrete, recycled asphalt concrete, tensile strength, moisture damage, creep
Procedia PDF Downloads 2722548 Multifunctionality of Cover Crops in South Texas: Looking at Multiple Benefits of Cover Cropping on Small Farms in a Subtropical Climate
Authors: Savannah Rugg, Carlo Moreno, Pushpa Soti, Alexis Racelis
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Situated in deep South Texas, the Lower Rio Grande Valley (LRGV) is considered one the most productive agricultural regions in the southern US. With the highest concentration of organic farms in the state (Hidalgo county), the LRGV has a strong potential to be leaders in sustainable agriculture. Finding management practices that comply with organic certification and increase the health of the agroecosytem and the farmers working the land is increasingly pertinent. Cover cropping, or the intentional planting of non-cash crop vegetation, can serve multiple functions in an agroecosystem by decreasing environmental pollutants that originate from the agroecosystem, reducing inputs needed for crop production, and potentially decreasing on-farm costs for farmers—overall increasing the sustainability of the farm. Use of cover crops on otherwise fallow lands have shown to enhance ecosystem services such as: attracting native beneficial insects (pollinators), increase nutrient availability in topsoil, prevent nutrient leaching, increase soil organic matter, and reduces soil erosion. In this study, four cover crops (Lablab, Sudan Grass, Sunn Hemp, and Pearl Millet) were analyzed in the subtropical region of south Texas to see how their multiple functions enhance ecosystem services. The four cover crops were assessed to see their potential to harbor native insects, their potential to increase soil nitrogen, to increase soil organic matter, and to suppress weeds. The preliminary results suggest that these subtropical varieties of cover crops have potential to enhance ecosystem services on agricultural land in the RGV by increasing soil organic matter (in all varieties), increasing nitrogen in topsoil (Lablab, Sunn Hemp), and reducing weeds (Sudan Grass).Keywords: cover crops, ecosystem services, subtropical agriculture, sustainable agriculture
Procedia PDF Downloads 2942547 Estimation Model for Concrete Slump Recovery by Using Superplasticizer
Authors: Chaiyakrit Raoupatham, Ram Hari Dhakal, Chalermchai Wanichlamlert
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This paper is aimed to introduce the solution of concrete slump recovery using chemical admixture type-F (superplasticizer, naphthalene base) to the practice, in order to solve unusable concrete problem due to concrete loss its slump, especially for those tropical countries that have faster slump loss rate. In the other hand, randomly adding superplasticizer into concrete can cause concrete to segregate. Therefore, this paper also develops the estimation model used to calculate amount of second dose of superplasticizer need for concrete slump recovery. Fresh properties of ordinary Portland cement concrete with volumetric ratio of paste to void between aggregate (paste content) of 1.1-1.3 with water-cement ratio zone of 0.30 to 0.67 and initial superplasticizer (naphthalene base) of 0.25%- 1.6% were tested for initial slump and slump loss for every 30 minutes for one and half hour by slump cone test. Those concretes with slump loss range from 10% to 90% were re-dosed and successfully recovered back to its initial slump. Slump after re-dosed was tested by slump cone test. From the result, it has been concluded that, slump loss was slower for those mix with high initial dose of superplasticizer due to addition of superplasticizer will disturb cement hydration. The required second dose of superplasticizer was affected by two major parameter, which were water-cement ratio and paste content, where lower water-cement ratio and paste content cause an increase in require second dose of superplasticizer. The amount of second dose of superplasticizer is higher as the solid content within the system is increase, solid can be either from cement particles or aggregate. The data was analyzed to form an equation use to estimate the amount of second dosage requirement of superplasticizer to recovery slump to its original.Keywords: estimation model, second superplasticizer dosage, slump loss, slump recovery
Procedia PDF Downloads 1952546 Enhancing Value of Dam Dredged Sediments as a Component of a Self Compacting Concrete
Authors: N. Belas, O. Belaribi, S. Aggoun, K. Bendani, N. Bouhamou, A. Mebrouki
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This experimental work is a part of a long research on the valorization of the dam dredged sediments issued from Fergoug Dam (Mascara-West Algeria). These sediments have to be subjected to thermal treatment to become reactive with the cement and thus to obtain an artificial pozzolana. It is therefore a question of developing the calcined mud as substitutable material in part to the cement used in the composition of self compacting concrete. The objective of the present work is to highlight its influence on the behavior of self compacting concrete compared to that of the natural pozzolana and this, in fresh and hardened states. The study is being conducted on three SCC, the first using 20% in volume of natural pozzolana, the second with 20 % of calcined mud and the third for the sake of comparison is made with cement only. The first results showed the possibility of obtaining SCC with calcined mud complying with the AFGC recommendations having a good mechanical behavior which makes interesting its development as construction materials.Keywords: dam, fresh state, hardened state mud, sediments, self compacting concrete, valorization
Procedia PDF Downloads 5052545 Use of Fine Recycled Aggregates in Normal Concrete Production
Authors: Vignesh Pechiappan Ayyathurai, Mukesh Limbachiya, Hsein Kew
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There is a growing interest in using recycled, secondary use and industrial by product materials in high value commercial applications. Potential high volume applications include use of fine aggregate in flowable fill or as a component in manufactured aggregates. However, there is much scientific, as well as applied research needed in this area due to lack to availability of data on the mechanical and environmental properties of elements or products produced using fine recycled aggregates. The principle objectives of this research are to synthesize existing data on the beneficial reuse of fine recycled materials and to develop extensive testing programme for assessing and establishing engineering and long term durability properties of concrete and other construction products produced using such material for use in practical application widely. This paper is a research proposal for PhD admission. The proposed research aims to supply the necessary technical, as well as practical information on fine recycled aggregate concrete to the construction industry for promoting its wider use within the construction industry. Furthermore, to disseminate research outcomes to the local authorities for consideration of use of fine recycled aggregate concrete in various applications.Keywords: FRA, fine aggregate, recycling, concrete
Procedia PDF Downloads 3172544 Behaviour of Hybrid Steel Fibre Reinforced High Strength Concrete
Authors: Emdad K. Z. Balanji, M. Neaz Sheikh, Muhammad N. S. Hadi
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This paper presents results of an experimental investigation on the behaviour of Hybrid Steel Fibre Reinforced High Strength Concrete (HSFR-HSC) cylinder specimens (150 mm x 300 mm) under uniaxial compression. Three different combinations of HSFR-HSC specimens and reference specimens without steel fibres were prepared. The first combination of HSFR-HSC included 1.5% Micro Steel (MS) fibre and 1% Deformed Steel (DS) fibre. The second combination included 1.5% MS fibre and 1.5% Hooked-end Steel (HS) fibre. The third combination included 1% DS fibre and 1.5% HS fibre. The experimental results showed that the addition of hybrid steel fibres improved the ductility of high strength concrete. The combination of MS fibre and HS fibre in high strength concrete mixes showed best stress-strain behaviour compared to the other combinations and the reference specimens.Keywords: high strength concrete, micro steel fibre (MS), deformed steel fibre (DS), hooked-end steel fibre (HS), hybrid steel fibre
Procedia PDF Downloads 5412543 Mechanical Properties and Durability of Concretes Manufactured Using Pre-Coated Recycled Fine Aggregate
Authors: An Cheng, Hui-Mi Hsu, Sao-Jeng Chao, Wei-Ting Lin
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This study investigated the mechanical properties and durability of concrete produced using recycled fine aggregate (RFA) pre-coated with fly ash, slag, and a polymer solution (PVA). We investigated the physical and microscopic properties of fresh concrete while adjusting several of the fabrication parameters, such as the constituent makeup and thickness of RFA pre-coatings. The study is divided into two parts. The first part involves mortar testing in which the RFA used for coating had a water/cement ratio of 0.5 and fly ash, slag, and PVA viscosity of 5~6cps, 21~26cps, 25~30cps, or 44~50cps. In these tests, 100% of the natural fine aggregate was replaced by RCA. The second part of the study involved the mixing of concrete with 25% FRA, which was respectively coated with fly ash, slag, or PVA at a viscosity of 44~50cps. In these tests, the water/cement ratio was either .4 or 0.6. The major findings in this study are summarized as follows: Coating RFA coated with fly ash and PVA was shown to increase flow in the fresh concrete; however, the coating of FRA with slag resulted in a slight decrease in flow. Coating FRA with slag was shown to improve the compressive and splitting strength to a greater degree than that achieved by coating FRA with fly ash and PVA. The mechanical properties of concrete mixed with slag were shown to increase with the thickness of the coating. Coating FRA with slag was also shown to enhance the durability of the concrete, regardless of the water/cement ratio.Keywords: recycled fine aggregates, pre-coated, fly ash, slag, pre-coated thickness
Procedia PDF Downloads 3192542 Thermodynamic Performance Tests for 3D Printed Steel Slag Powder Concrete Walls
Authors: Li Guoyou, Zhang Tao, Ji Wenzhan, Huo Liang, Lin Xiqiang, Zhang Nan
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The three dimensional (3D) printing technology has undergone rapid development in the last few years and it is possible to print engineering structures. 3D printing buildings use wastes from constructions, industries and mine tailings as “ink”, and mix it with property improved materials, such as cement, fiber etc. This paper presents a study of the Thermodynamic performance of 3D printed walls using cement and steel slag powder. Analyses the thermal simulation regarding 3D printed walls and solid brick wall by the way of the hot-box methods and the infrared technology, and the results were contrasted with theoretical calculation. The results show that the excellent thermodynamic performance of 3D printed concrete wall made it suitable as the partial materials for self-thermal insulation walls in residential buildings. The thermodynamic performance of 3D printed concrete walls depended on the density of materials, distribution of holes, and the filling materials. Decreasing the density of materials, increasing the number of holes or replacing the filling materials with foamed concrete could improve its thermodynamic performance significantly. The average of heat transfer coefficient and thermal inertia index of 3D printed steel slag powder concrete wall all better than the traditional solid brick wall with a thickness of 240mm.Keywords: concrete, 3D printed walls, thermodynamic performance, steel slag powder
Procedia PDF Downloads 179