Search results for: asphalt pavements

Authors: Rideci Farias, Haroldo Paranhos

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The present work deals with the use of drainage geo-composite as a deep drainage and geogrid element to reinforce the base of the body of the landfill destined to the road pavement on geological faults in the stretch of the TO-342 Highway, between the cities of Miracema and Miranorte, in the State of Tocantins / TO, Brazil, which for many years was the main link between TO-010 and BR-153, after the city of Palmas, also in the state of Tocantins / TO, Brazil. For this application, geotechnical and geological studies were carried out by means of SPT percussion drilling, drilling and rotary drilling, to understand the problem, identifying the type of faults, filling material and the definition of the water table. According to the geological and geotechnical studies carried out, the area where the route was defined, passes through a zone of longitudinal fault to the runway, with strong breaking / fracturing, with presence of voids, intense alteration and with advanced argilization of the rock and with the filling up parts of the faults by organic and compressible soils leachate from other horizons. This geology presents as a geotechnical aggravating agent a medium of high hydraulic load and very low resistance to penetration. For more than 20 years, the region presented constant excessive deformations in the upper layers of the pavement, which after routine services of regularization, reconformation, re-compaction of the layers and application of the asphalt coating. The faults were quickly propagated to the surface of the asphalt pavement, generating a longitudinal shear, forming steps (unevenness), close to 40 cm, causing numerous accidents and discomfort to the drivers, since the geometric positioning was in a horizontal curve. Several projects were presented to the region's highway department to solve the problem. Due to the need for partial closure of the runway, the short time for execution, the use of geosynthetics was proposed and the most adequate solution for the problem was taken into account the movement of existing geological faults and the position of the water level in relation to several Layers of pavement and failure. In order to avoid any flow of water in the body of the landfill and in the filling material of the faults, a drainage curtain solution was used, carried out at 4.0 meters depth, with drainage geo-composite and as reinforcement element and inhibitor of the possible A geogrid of 200 kN / m of resistance was inserted at the base of the reconstituted landfill. Recent evaluations, after 13 years of application of the solution, show the efficiency of the technique used, supported by the geotechnical studies carried out in the area.

Keywords: geosynthetics, geocomposite, geogrid, road, recovery, geological failure

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Authors: Ainura Kairanbayeva

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Currently, the issue of maintaining the operational condition of highways at the required level is acute in Kazakhstan. The impact of landslides on the state of the road industry in Kazakhstan has been poorly studied. This article presents the classification of natural hazards and examines the influence of atmospheric natural processes on the operational condition of the sections of the highway "Ayusai–Kosmostantsia" passing along the mountain slopes of the Trans-Ili Alatau. According to the results of field studies, multi-turn reflected cracks have been identified, this is also due to the fact that the base of the road is made of a sand-gravel mixture and is not treated with reinforcing additives and the actual density of the asphalt concrete pavement is below regulatory requirements.

Keywords: building materials and products, construction of highways and engineering structures, construction processes, displacements of the earth's surface, geodynamic processes

Procedia PDF Downloads 52

Authors: Alireza Rezagholilou

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Moisture susceptibility of bituminous mixes directly affect the stripping of asphalt layers. The majority of relevant test methods are mechanical methods with low repeatability and consistency of results. Thus, this research aims to evaluate the physicochemical interactions of bitumen and aggregates based on the wettability concept. As such, the surface energies of components at the interface are measured by contact angle method. That gives an opportunity to investigate the adhesion properties of multiple mineral fillers at various percentages to explore the best dosage in the mix. Three types of fillers, such as hydrated lime, ground lime and rock powder, are incorporated into the bitumen mix for a series of sessile drop tests for both aggregates and binders. Results show the variation of adhesion properties versus filler (%).

Keywords: adhesion, contact angle, filler, surface energy, moisture susceptibility

Procedia PDF Downloads 52

Authors: R. Islam, Rafiqul A. Tarefder

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This study presents the moisture variations of unbound layers from April 2012 to January 2014 in the Interstate 40 (I-40) pavement section in New Mexico. Three moisture probes were installed at different layers inside the pavement which measure the continuous moisture variations of the pavement. Data show that the moisture contents of unbound layers are typically constant throughout the day and month unless there is rainfall. Moisture contents of all unbound layers change with rainfall. Change in ground water table may affect the moisture content of unbound layers which has not investigated in this study. In addition, the Level 3 predictions of moisture contents using the Pavement Mechanistic-Empirical (ME) Design software are compared and found quite reasonable. However, results presented in the current study may not be applicable for pavement in other regions.

Keywords: asphalt pavement, moisture probes, resilient modulus, climate model

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Authors: M. Sirhan, S. Bekhor, A. Sidess

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In-service pavements deteriorate with time due to traffic wheel loads, environment, and climate conditions. Pavement deterioration leads to a reduction in their serviceability and structural behavior. Consequently, proper maintenance and rehabilitation (M&R) are necessary actions to keep the in-service pavement network at the desired level of serviceability. Due to resource and financial constraints, the pavement management system (PMS) prioritizes roads most in need of maintenance and rehabilitation action. It recommends a suitable action for each pavement based on the performance and surface condition of each road in the network. The pavement performance and condition are usually quantified and evaluated by different types of roughness-based and stress-based indices. Examples of such indices are Pavement Serviceability Index (PSI), Pavement Serviceability Ratio (PSR), Mean Panel Rating (MPR), Pavement Condition Rating (PCR), Ride Number (RN), Profile Index (PI), International Roughness Index (IRI), and Pavement Condition Index (PCI). PCI is commonly used in PMS as an indicator of the extent of the distresses on the pavement surface. PCI values range between 0 and 100; where 0 and 100 represent a highly deteriorated pavement and a newly constructed pavement, respectively. The PCI value is a function of distress type, severity, and density (measured as a percentage of the total pavement area). PCI is usually calculated iteratively using the 'Paver' program developed by the US Army Corps. The use of soft computing techniques, especially Artificial Neural Network (ANN), has become increasingly popular in the modeling of engineering problems. ANN techniques have successfully modeled the performance of the in-service pavements, due to its efficiency in predicting and solving non-linear relationships and dealing with an uncertain large amount of data. Typical regression models, which require a pre-defined relationship, can be replaced by ANN, which was found to be an appropriate tool for predicting the different pavement performance indices versus different factors as well. Subsequently, the objective of the presented study is to develop and train an ANN model that predicts the PCI values. The model’s input consists of percentage areas of 11 different damage types; alligator cracking, swelling, rutting, block cracking, longitudinal/transverse cracking, edge cracking, shoving, raveling, potholes, patching, and lane drop off, at three severity levels (low, medium, high) for each. The developed model was trained using 536,000 samples and tested on 134,000 samples. The samples were collected and prepared by The National Transport Infrastructure Company. The predicted results yielded satisfactory compliance with field measurements. The proposed model predicted PCI values with relatively low standard deviations, suggesting that it could be incorporated into the PMS for PCI determination. It is worth mentioning that the most influencing variables for PCI prediction are damages related to alligator cracking, swelling, rutting, and potholes.

Keywords: artificial neural networks, computer programming, pavement condition index, pavement management, performance prediction

Procedia PDF Downloads 108

Authors: I. Goual, M. S. Goual, M. K. Gueddouda, Taïbi Saïd, Abou-Bekr Nabil, A. Ferhat

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The aim of the paper is to study the hydro-mechanical behavior of a tuff and calcareous sand mixture. A first experimental phase was carried out in order to find the optimal mixture. This showed that the material composed of 80% tuff and 20% calcareous sand provides the maximum mechanical strength. The second experimental phase concerns the study of the drying-wetting behavior of the optimal mixture was carried out on slurry samples and compacted samples at the MPO. Experimental results let to deduce the parameters necessary for the prediction of the hydro-mechanical behavior of pavement formulated from tuff and calcareous sand mixtures, related to moisture. This optimal mixture satisfies the regulation rules and hence constitutes a good local eco-material, abundantly available, for the conception of pavements.

Keywords: tuff, sandy calcareous, road engineering, hydro mechanical behaviour, suction

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Authors: Shamsulhaq Amin

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Unbound granular materials (UGMs) are pivotal in ensuring long-term quality, especially in the layers under the surface of flexible pavements and other constructions. This study seeks to better understand the behavior of the UGMs by looking at popular models for predicting lasting deformation under various levels of stresses and load cycles. These models focus on variables such as the number of load cycles, stress levels, and features specific to materials and were evaluated on the basis of their ability to accurately predict outcomes. The study showed that these factors play a crucial role in how well the models work. Therefore, the research highlights the need to look at a wide range of stress situations to more accurately predict how much the UGMs bend or shift. The research looked at important factors, like how permanent deformation relates to the number of times a load is applied, how quickly this phenomenon happens, and the shakedown effect, in two different types of UGMs: granite and limestone. A detailed study was done over 100,000 load cycles, which provided deep insights into how these materials behave. In this study, a number of factors, such as the level of stress applied, the number of load cycles, the density of the material, and the moisture present were seen as the main factors affecting permanent deformation. It is vital to fully understand these elements for better designing pavements that last long and handle wear and tear. A series of laboratory tests were performed to evaluate the mechanical properties of materials and acquire model parameters. The testing included gradation tests, CBR tests, and Repeated load triaxial tests. The repeated load triaxial tests were crucial for studying the significant components that affect deformation. This test involved applying various stress levels to estimate model parameters. In addition, certain model parameters were established by regression analysis, and optimization was conducted to improve outcomes. Afterward, the material parameters that were acquired were used to construct graphs for each model. The graphs were subsequently compared to the outcomes obtained from the repeated load triaxial testing. Additionally, the models were evaluated to determine if they demonstrated the two inherent deformation behaviors of materials when subjected to repetitive load: the initial phase, post-compaction, and the second phase volumetric changes. In this study, using log-log graphs was key to making the complex data easier to understand. This method made the analysis clearer and helped make the findings easier to interpret, adding both precision and depth to the research. This research provides important insight into picking the right models for predicting how these materials will act under expected stress and load conditions. Moreover, it offers crucial information regarding the effect of load cycle and permanent deformation as well as the shakedown effect on granite and limestone UGMs.

Keywords: permanent deformation, unbound granular materials, load cycles, stress level

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Authors: S. K. Khosrowshahi, E. Güler

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This study investigates the reinforcement function of geosynthetics on the shear strength and strain profile of sand. Conducting a series of simple shear tests, the shearing behavior of the samples under static and cyclic loads was evaluated. Three different types of geosynthetics including geotextile and geonets were used as the reinforcement materials. An image processing analysis based on the optical flow method was performed to measure the lateral displacements and estimate the shear strains. It is shown that besides improving the shear strength, the geosynthetic reinforcement leads a remarkable reduction on the shear strains. The improved layer reduces the required thickness of the soil layer to resist against shear stresses. Consequently, the geosynthetic reinforcement can be considered as a proper approach for the sustainable designs, especially in the projects with huge amount of geotechnical applications like subgrade of the pavements, roadways, and railways.

Keywords: image processing, soil reinforcement, geosynthetics, simple shear test, shear strain profile

Procedia PDF Downloads 198

Authors: Abdelkader Soumaya, Noureddine Ben Ayed, Ali Kadri, Said Maouche, Hayet Khayati Ammar, Ahmed Braham

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The historic sites of Bulla Regia and Chemtou are among the most important archaeological monuments in northwestern Tunisia, which flourished as large, wealthy settlements during the Roman and Byzantine periods (2nd to 7th centuries AD). An archaeoseismological study provides the first indications about the impact of a possible ancient strong earthquake in the destruction of these cities. Based on previous archaeological excavation results, including numismatic evidence, pottery, economic meltdown and urban transformation, the abrupt ruin and destruction of the cities of Bulla Regia and Chemtou can be bracketed between 613 and 647 AD. In this study, we carried out the first attempt to use the analysis of earthquake archaeological effects (EAEs) that were observed during our field investigations in these two historic cities. The damage includes different types of EAEs: folds on regular pavements, displaced and deformed vaults, folded walls, tilted walls, collapsed keystones in arches, dipping broken corners, displaced-fallen columns, block extrusions in walls, penetrative fractures in brick-made walls and open fractures on regular pavements. These deformations are spread over 10 different sectors or buildings and include 56 measured EAEs. The structural analysis of the identified EAEs can indicate an ancient destructive earthquake that probably destroyed the Bulla Regia and Chemtou archaeological sites. We then analyzed these measurements using structural geological analysis to obtain the maximum horizontal strain of the ground (e.g., S ₕₘₐₓ) on each building-oriented damage. After the collection and analysis of these strain datasets, we proceed to plot the orientation of Sₕₘₐₓ trajectories on the map of the archaeological site (Bulla Regia). We concluded that the obtained Sₕₘₐₓ trajectories within this site could then be related to the mean direction of ground motion (oscillatory movement of the ground) triggered by a seismic event, as documented for some historical earthquakes across the world. These Sₕₘₐₓ orientations closely match the current active stress field, as highlighted by some instrumental events in northern Tunisia. In terms of the seismic source, we strongly suggest that the reactivation of a neotectonic strike-slip fault trending N50E must be responsible for this probable historic earthquake and the recent instrumental seismicity in this area. This fault segment, affecting the folded quaternary deposits south of Jebel Rebia, passes through the monument of Bulla Regia. Stress inversion of the observed and measured data along this fault shows an N150 - 160 trend of Sₕₘₐₓ under a transpressional tectonic regime, which is quite consistent with the GPS data and the state of the current stress field in this region.

Keywords: NW Tunisia, archaeoseismology, earthquake archaeological effect, bulla regia - Chemtou, seismotectonic, neotectonic fault

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Authors: Paulos Meles Yihdego

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To address the environmental impact of the cement industry and road building waste, the use of chemical stabilizers in conjunction with recycled asphalt and cement components was investigated. The silica-based chemical stabilizers and their potential effects on the base layer stabilized by cement are discussed in this paper. Strength, moisture compaction interaction, and microstructural characteristics are all examined. According to the outcome, using this stabilizer has improved the mechanical properties. The inclusion of chemical stabilizers in the combination, which is responsible for the mixture's improved strength, raised the intensity of the C-S-H (Calcium Silicate Hydrate) gel, according to a microstructural study. The design was demonstrated to be durable by the little ettringites found in the later phases. The application of this stabilizer ensures a strong, eco-friendly, durable base layer.

Keywords: ettringites, microstructure analysis, durability properties, cement stabilized base

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Authors: A. Fettahoglu

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Theory of viscoelasticity is used by many researchers to represent the behavior of many materials such as pavements on roads or bridges. Several researches used analytical methods and rheology to predict the material behaviors of simple models. Today, more complex engineering structures are analyzed using Finite Element Method, in which material behavior is embedded by means of three dimensional viscoelastic material laws. As a result, structures of unordinary geometry and domain can be analyzed by means of Finite Element Method and three dimensional viscoelastic equations. In the scope of this study, rheological models embedded in ANSYS, namely, generalized Maxwell model and Prony series, which are two methods used by ANSYS to represent viscoelastic material behavior, are presented explicitly. Afterwards, a guide is illustrated to ease using of viscoelasticity tool in ANSYS.

Keywords: ANSYS, generalized Maxwell model, finite element method, Prony series, viscoelasticity, viscoelastic material curve fitting

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Authors: Janusz Kwaśniewski, Ireneusz Dominik, Krzysztof Lalik

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The knowledge about rock layers thickness, especially above drilled mining pavements are crucial for workers safety. The measuring systems used nowadays are generally imperfect and there is a strong demand for improvement. The application of a new type of a measurement system called Self-Excited Acoustical System is presented in the paper. The system was applied until now to monitor stress changes in metal and concrete constructions. The change in measurement methodology resulted in possibility of measuring the thickness of the rocks above the tunnels as well as thickness of a singular rock layer. The idea is to find two resonance frequencies of the self-exited system, which consists of a vibration exciter and vibration receiver placed at a distance, which are coupled with a proper power amplifier, and which operate in a closed loop with a positive feedback. The resonance with the higher amplitude determines thickness of the whole rock, whereas the lower amplitude resonance indicates thickness of a singular layer. The results of the laboratory tests conducted on a group of different rock materials are also presented.

Keywords: auto-oscillator, non-destructive testing, rock thickness measurement, geotechnic

Procedia PDF Downloads 351

Authors: Burak Yigit Katanalp, Murat Tastan, Perviz Ahmedzade, çIgdem Canbay Turkyilmaz, Emrah Turkyilmaz

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This study evaluated the mechanical and rheological performance of fly ash-based geopolymer at high temperatures. A series of laboratory tests were conducted on neat bitumen and three modified bitumen samples, which incorporated fly ash-based geopolymer at various percentages. Low-calcium fly ash was used as the alumina-silica source. The dynamic shear rheometer and rotational viscometer were employed to determine high-temperature properties, while conventional tests such as penetration and softening point were used to evaluate the physical properties of bitumen. The short-term aging resistance of the samples was assessed using the rolling thin film oven. The results show that geopolymer has a compromising effect on bitumen properties, with improved stiffness, enhanced mechanical strength, and increased thermal susceptibility of the asphalt binder.

Keywords: bitumen, geopolymer, modification, dynamic mechanical analysis

Procedia PDF Downloads 67

Authors: Manju, Praveen Aggarwal

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Clayey soil is considered weakest subgrade soil from civil engineering point of view under moist condition. These swelling soils attract and absorb water and losses their strength. Certain inherent properties of these clayey soils need modification for their bulk use in the construction of highways/runways pavements and embankments, etc. In this paper, results of clayey subgrade modified with cement stabilizer is presented. Investigation includes evaluation of specific gravity, Atterberg’s limits, grain size distribution, maximum dry density, optimum moisture content and CBR value of the clayey soil and cement treated clayey soil. A series of proctor compaction and CBR tests (un-soaked and soaked) are carried out on clayey soil and clayey soil mixed with cement stabilizer in 2%, 4% & 6% percentages to the dry weight of soil. In CBR test, under soaked condition best results are obtained with 6% of cement. However, the difference between the CBR value by addition of 4% and 6% cement is not much. Therefore from economical consideration addition of 4% cement gives the best result after soaking period of 90 days.

Keywords: clayey soil, cement, maximum dry density, optimum moisture content, California bearing ratio

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Authors: S. M. Gupta, Vanita Aggarwal, Som Nath Sachdeva

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The work reported through this paper is an experimental work conducted on High Performance Concrete (HPC) with super plasticizer with the aim to develop some models suitable for prediction of compressive strength of HPC mixes. In this study, the effect of varying proportions of fly ash (0% to 50% at 10% increment) on compressive strength of high performance concrete has been evaluated. The mix designs studied were M30, M40 and M50 to compare the effect of fly ash addition on the properties of these concrete mixes. In all eighteen concrete mixes have been designed, three as conventional concretes for three grades under discussion and fifteen as HPC with fly ash with varying percentages of fly ash. The concrete mix designing has been done in accordance with Indian standard recommended guidelines i.e. IS: 10262. All the concrete mixes have been studied in terms of compressive strength at 7 days, 28 days, 90 days and 365 days. All the materials used have been kept same throughout the study to get a perfect comparison of values of results. The models for compressive strength prediction have been developed using Linear Regression method (LR), Artificial Neural Network (ANN) and Leave One Out Validation (LOOV) methods.

Keywords: high performance concrete, fly ash, concrete mixes, compressive strength, strength prediction models, linear regression, ANN

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Authors: Bao Thach Nguyen, Abbas Mohajerani

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The California bearing ratio (CBR) has been acknowledged as an important parameter to characterize the bearing capacity of earth structures, such as earth dams, road embankments, airport runways, bridge abutments, and pavements. Technically, the CBR test can be carried out in the laboratory or in the field. The CBR test is time-consuming and is infrequently performed due to the equipment needed and the fact that the field moisture content keeps changing over time. Over the years, many correlations have been developed for the prediction of CBR by various researchers, including the dynamic cone penetrometer, undrained shear strength, and Clegg impact hammer. This paper reports and discusses some of the results from a study on the prediction of CBR. In the current study, the CBR test was performed in the laboratory on some fine-grained subgrade soils collected from various locations in Victoria. Based on the test results, a satisfactory empirical correlation was found between the CBR and the physical properties of the experimental soils.

Keywords: California bearing ratio, fine-grained soils, soil physical properties, pavement, soil test

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Authors: Samiullah Bhatti, Safdar Abbas Zaidi, Syed Murtaza Ali Jafri

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This research paper presents the results of using plastic aggregate in flexible pavement. Plastic aggregates have been prepared with polypropylene (PP) recycled products and have been tested with Marshall apparatus. Grade 60/70 bitumen has been chosen for this research with a total content of 2.5 %, 3 % and 3.5 %. Plastic aggregates are mixed with natural aggregates with different proportions and it ranges from 10 % to 100 % with an increment of 10 %. Therefore, a total of 10 Marshall cakes were prepared with plastic aggregates in addition to a standard pavement sample. In total 33 samples have been tested for Marshall stability, flow and voids in mineral aggregates. The results show an increase in the value when it changes from 2.5 % bitumen to 3 % and after then it goes again toward declination. Thus, 3 % bitumen content has been found as the most optimum value for flexible pavements. Among all the samples, 20 % PP aggregates sample has been found satisfactory with respect to all the standards provided by ASTM. Therefore, it is suggested to use 20 plastic aggregates in flexible pavement construction. A comparison of bearing capacity and skid resistance is also observed.

Keywords: marshall test, polypropylene plastic, plastic aggregates, flexible pavement alternative, recycling of plastic waste

Procedia PDF Downloads 108

Authors: Hocini Yousra, Medjnoun Amal, Khiatine Mohamed, Bahar Ramdane

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The development of the regions of southern Algeria require the construction of numerous road, rail, and airport infrastructures. However, this development is very expensive given the very severe climatic conditions, the difficulty of reusing local materials, and the unavailability of water on the project sites; these regions are characterized by an arid or semi-arid climate, which means that water sources are very limited. The climatic conditions and the scarcity of water make soil compaction work very difficult and excessively expensive. These constraints related to the supply of water for irrigation of these construction sites make it necessary to examine the solution of compaction with low water content. This work studies the possibility of improving the compaction with a low water content of the soils of southern Algeria and this by using natural or recycled ecological materials. Local soils are first subjected to a series of laboratory characterization tests, then mixed with varying amounts of natural additives. The new materials are, in turn, subjected to road tests.

Keywords: compaction, low water content, sand, natural materials

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Authors: Toufic Abd El-Latif Sadek

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The concrete object represents the concrete areas, like buildings. The best, easy, and efficient extraction of the concrete object from satellite thermal images occurred at specific times during the days of the year, by preventing the gaps in times which give the close and same brightness from different objects. Thus, to achieve the best original data which is the aim of the study and then better extraction of the concrete object and then better analysis. The study was done using seven sample objects, asphalt, concrete, metal, rock, dry soil, vegetation, and water, located at one place carefully investigated in a way that all the objects achieve the homogeneous in acquired data at the same time and same weather conditions. The samples of the objects were on the roof of building at position taking by global positioning system (GPS) which its geographical coordinates is: Latitude= 33 degrees 37 minutes, Longitude= 35 degrees 28 minutes, Height= 600 m. It has been found that the first choice and the best time in February is at 2:00 pm, in March at 4 pm, in April and may at 12 pm, in August at 5:00 pm, in October at 11:00 am. The best time in June and November is at 2:00 pm.

Keywords: best timing, concrete areas, optimal, satellite thermal images

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Authors: Jaime Carpio-García, Elena Blanco-Fernández, Javier González-Fernández, Daniel Castro-Fresno

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Sustainable urban drainage systems (SUDS) are more often used in order to prevent floods, water treatment, fight against pollution, urban heat island effect, and global warming in applications like green roofs, permeable pavements, and others. Furthermore, geosynthetics are also worldwide used as a part of drainage systems in road construction. Geotextiles are an essential part of both, and one of the main geotextile properties in those applications is permeability, whose behavior is not well established along its service life. In this paper, clogging reduction design factors for an estimated service life of 25 years are experimentally obtained for five different geotextiles used in SUDS and roads combined with two different soils and with two pollutants, motor oil, and lime, in order to evaluate chemical clogging, too. The effect of characteristic opening size and other characteristics of the geosynthetics are also discussed in order to give civil engineers, together with the clogging reduction factors, a better long-time design of geotextiles used in their SUDS and roads.

Keywords: geotextiles, drainage, clogging, reduction factor

Procedia PDF Downloads 47

Authors: Chamroeun Chhorn, Seong Jae Hong, Yoon-Ho Cho, Hyun Jong Lee, Seung Woo Lee

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The use of Roller-Compacted Concrete Pavement (RCCP) in public and private applications has been increasing steadily in the past few decades due to its cost saving. This eco-concrete pavement shares construction characteristics from asphalt pavement and material characteristics from the conventional concrete pavement. Due to its low binder and water content, the consistency of Roller-Compacted Concrete (RCC) is typically very stiff. Thus, it is crucial to control the consistency of this concrete. Without appropriate consistency, required density may not be achieved in actual construction for RCCP. The purpose of this study is to investigate the effect on Poly Naphtalene Sulfonate (PNS) superplasticizer on the consistency of RCC as well as its compactibility in actual construction. From this study, it was found that PNS superplasticizer can effectively reduce the stiffness of an RCC mixture and maintain it for a sufficient amount of time without compromising its strength properties. Moreover, it was observed from field test specimens that the use of this admixture can also improve the compaction efficiency throughout the whole depth of pavement.

Keywords: roller-compacted concrete, consistency, compactibility, poly naphthalene sulfonate superplasticizer

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Authors: Dang Hanh Nguyen, Nassim Sebaibi, Mohamed Boutouil, Lydia Leleyter, Fabienne Baraud

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Pervious concrete is a green alternative to conventional pavements with minimal fine aggregate and a high void content. Pervious concrete allows water to infiltrate through the pavement, thereby reducing the runoff and the requirement for stormwater management systems. Seashell By-Products (SBP) are produced in an important quantity in France and are considered as waste. This work investigated to use SBP in pervious concrete and produce an even more environmentally friendly product, Pervious Concrete Pavers. The research methodology involved substituting the coarse aggregate in the previous concrete mix design with 20%, 40% and 60% SBP. The testing showed that pervious concrete containing less than 40% SBP had strengths, permeability and void content which are comparable to the pervious concrete containing with only natural aggregate. The samples that contained 40% SBP or higher had a significant loss in strength and an increase in permeability and a void content from the control mix pervious concrete. On the basis of the results in this research, it was found that the natural aggregate can be substituted by SBP without affecting the delicate balance of a pervious concrete mix. Additional, it is recommended that the optimum replacement percentage for SBP in pervious concrete is 40 % direct replacement of natural coarse aggregate while maintaining the structural performance and drainage capabilities of the pervious concrete.

Keywords: seashell by-products, pervious concrete pavers, permeability, mechanical strength

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Authors: J. Hemanth, B. G. Shivaprakash, S. V. Dinesh

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The locally available Lateritic soil in Dakshina Kanadda and Udupi districts are traditionally being used as building blocks for construction purpose but they do not meet the conventional requirements (L L ≤ 25% & P I ≤6%) and desired four days soaked CBR value to be used as a sub-base course material in pavements. In order to improve its properties to satisfy the Atterberg’s Limits, the soil is blended with sand, cement and quarry dust at various percentages and also to meet the CBR strength requirements, individual and combined gradation of various sized aggregates along with Laterite soil and other filler materials has been done for coarse graded granular sub-base materials (Grading II and Grading III). The effect of additives blended with lateritic soil and aggregates are studied in terms of Atterberg’s limits, compaction, California Bearing Ratio (CBR), and permeability. It has been observed that the addition of sand, cement and quarry dust are found to be effective in improving Atterberg’s limits, CBR values, and permeability values. The obtained CBR and permeability values of Grading III, and Grading II materials found to be sufficient to be used as sub-base course for low volume roads and high volume roads respectively.

Keywords: lateritic soil, sand, quarry dust, gradation, sub-base course, permeability

Procedia PDF Downloads 290

Authors: Cesar Maximo Oliva González, Javier Acevedo Cortez, Boris Kharisov, Thelma Serrano Quezada

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The importance of the crude oil refining process is due to the demand for petroleum products such as gasoline, kerosene, asphalt, etc., which are used in daily activities and have a high impact on the global economy. In the processes of oil obtaining and refining, it is common to find problems such as spills on seabed and high energy consumption in processing. In order to quickly and efficiently attack these problems, the use of adsorbents has taken on great importance due to its ease of implementation, as well as the possibility of their regeneration to be reused. In this work, the use of two types of adsorbents is proposed: the first is a natural adsorbent such as aloe vera or nopal, which were lyophilized and hydrophobized to achieve a selectivity in oil adsorption in oil / water mixtures. The second is a mixed iron/nickel oxide, which is specially designed to adsorb the asphaltenes in the heavy fractions of the oil; in addition, this type of adsorbents presents catalytic properties that manage to decompose the heavier fractions of the petroleum in light hydrocarbons, descending thus the energy required for the oil refining process.

Keywords: nanomaterials, oil spills, remediation, natural adsorbents, mixed oxides

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Authors: Iuri Salukvadze

Abstract:

Construction takes importance role in the history of mankind, there is not a single thing-product in our lives in which the builder’s work was not to be materialized, because to create all of it requires setting up factories, roads, and bridges, etc. The function of the Republic of Georgia, as part of the connecting Europe-Asia transport corridor, is significantly increased. In the context of transit function a large part of the cargo traffic belongs to motor transport, hence the improvement of motor roads transport infrastructure is rather important and rise the new, increased operational demands for existing as well as new motor roads. Construction of the durable road surface is related to rather large values, but because of high transport-operational properties, such as high-speed, less fuel consumption, less depreciation of tires, etc. If the traffic intensity is high, therefore the reimbursement of expenses occurs rapidly and accordingly is increasing income. If the traffic intensity is relatively small, it is recommended to use lightened structures of road carpet in order to pay for capital investments amounted to no more than normative one. The road carpet is divided into the following basic types: asphaltic concrete and cement concrete. Asphaltic concrete is the most perfect type of road carpet. It is arranged in two or three layers on rigid foundation and will be compacted. Asphaltic concrete is artificial building material, which due stratum will be selected and measured from stone skeleton and sand, interconnected by bitumen and a mixture of mineral powder. Less strictly selected similar material is called as bitumen-mineral mixture. Asphaltic concrete is non-rigid building material and well durable on vertical loadings; it is less resistant to the impact of horizontal forces. The cement concrete is monolithic and durable material, it is well durable the horizontal loads and is less resistant related to vertical loads. The cement concrete consists from strictly selected, measured stone material and sand, the binder is cement. The cement concrete road carpet represents separate slabs of sizes from 3 ÷ 5 op to 6 ÷ 8 meters. The slabs are reinforced by a rather complex system. Between the slabs are arranged seams that are designed for avoiding of additional stresses due temperature fluctuations on the length of slabs. For the joint behavior of separate slabs, they are connected by metal rods. Rods provide the changes in the length of slabs and distribute to the slab vertical forces and bending moments. The foundation layers will be extremely durable, for that is required high-quality stone material, cement, and metal. The qualification work aims to: in order for improvement of traffic conditions on motor roads to prolong operational conditions and improving their characteristics. The work consists from three chapters, 80 pages, 5 tables and 5 figures. In the work are stated general concepts as well as carried out by various companies using modern methods tests and their results. In the chapter III are stated carried by us tests related to this issue and specific examples to improving the operational characteristics.

Keywords: asphalt, cement, cylindrikal sample of asphalt, building

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Authors: Fathi Ali Swaid

Abstract:

The CBR test is widely used in the assessment of granular materials in base, subbase and subgrade layers of road and airfield pavements. Despite the success of this method, but it depends on a limited numbers of soil samples. This limitation do not adequately account for the spatial variability of soil properties. Thus, assessment is derived using these cursory soil data are likely to contain errors and thus make interpretation and soil characterization difficult. On the other hand quantitative methods of soil inventory at the field scale involve the design and adoption of sampling regimes and laboratory analysis that are time consuming and costly. In the latter case new technologies are required to efficiently sample and observe the soil in the field. This is particularly the case where soil bearing capacity is prevalent, and detailed quantitative information for determining its cause is required. In this paper, an electrical resistivity method DC is described and its application in Elg'deem Dirt road, located in Gasser Ahmad - Misurata, Libya. Results from the DC instrument were found to be correlated with the CBR values (r2 = 0.89). Finally, it is noticed that, the correlation can be used with experience for determining CBR value using basic soil electrical resistivity measurements and checked by few CBR test representing a similar range of CBR.

Keywords: California bearing ratio, basic soil electrical resistivity, CBR, soil, subgrade, new technologies

Procedia PDF Downloads 429

Authors: Ashkan Nazari, Saied Taheri

Abstract:

Knowledge of tire-pavement interaction plays a crucial role in designing safer and more reliable tires. Characterizing the tire-pavement frictional interaction leads to a better understanding of vehicle performance in braking and acceleration. In this work, we devise a multi-scale simulation approach to incorporate the effect of pavement surface asperities in different length-scales. We construct two- and three-dimensional Finite Element (FE) models to simulate the interaction between a rubber block and a rough pavement surface with asperities in different scales. To achieve this, the road profile is scanned via a laser profilometer and the obtained asperities are implemented in an FE software (ABAQUS) in micro and macro length-scales. The hysteresis friction, which is due to the dissipative nature of rubber, is the main component of the friction force and therefore is the subject of study in this work. Using different scales not only will assist in characterizing the pavement asperities with sufficient details but also, it is highly effective in preventing extreme local deformations and stress gradients which results in divergence in FE simulations. The simulation results will be validated with experimental results as well as the results reported in the literature.

Keywords: friction, finite element, multi-scale modeling, rubber

Procedia PDF Downloads 109

Authors: Woo-Tai Jung, Sung-Yong Choi, Young-Hwan Park

Abstract:

The composite pavement system considered in this paper is composed of a functional surface layer, a fiber reinforced asphalt middle layer and a fiber reinforced lean concrete base layer. The mix design of the fiber reinforced lean concrete corresponds to the mix composition of conventional lean concrete but reinforced by fibers. The quasi-absence of research on the durability or long-term performances (fatigue, creep, etc.) of such mix design stresses the necessity to evaluate experimentally the long-term characteristics of this layer composition. This study tests the creep characteristics as one of the long-term characteristics of the fiber reinforced lean concrete layer for composite pavement using a new creep device. The test results reveal that the lean concrete mixed with fiber reinforcement and fly ash develops smaller creep than the conventional lean concrete. The results of the application of the CEB-FIP prediction equation indicate that a modified creep prediction equation should be developed to fit with the new mix design of the layer.

Keywords: creep, lean concrete, pavement, fiber reinforced concrete, base

Procedia PDF Downloads 499

Authors: Femy M. Makkar, S. Chandrakaran, N. Sankar

Abstract:

The concept of reinforced earth has been used in the field of geotechnical engineering since 1960s, for many applications such as, construction of road and rail embankments, pavements, retaining walls, shallow foundations, soft ground improvement and so on. Conventionally, planar geosynthetic materials such as geotextiles and geogrids were used as the reinforcing elements. Recently, the use of three dimensional reinforcements becomes one of the emerging trends in this field. So, in the present investigation, three dimensional geogrid is proposed as a reinforcing material. Laboratory scaled plate load tests are conducted on a model square footing resting on 3D geogrid reinforced sand bed. The performance of 3D geogrids in triangular and square pattern was compared with conventional geogrids and the improvement in bearing capacity and reduction in settlement and heave are evaluated. When single layer of reinforcement was placed at an optimum depth of 0.25B from the bottom of the footing, the bearing capacity of conventional geogrid reinforced soil improved by 1.85 times compared to unreinforced soil, where as 3D geogrid reinforced soil with triangular pattern and square pattern shows 2.69 and 3.05 times improvement respectively compared to unreinforced soil. Also, 3D geogrids performs better than conventional geogrids in reducing the settlement and heave of sand bed around the model footing.

Keywords: 3D reinforcing elements, bearing capacity, heavy, settlement

Procedia PDF Downloads 269

Authors: Kidus Dawit Gedamu

Abstract:

Addis Ababa City Road Authority is responsible for managing and setting performance evaluation of the city’s road network using the International Roughness Index (IRI). This helps the authority to conduct pavement condition assessments of asphalt roads each year to determine the health status or Level of service (LOS) of the roadway network and plan program improvements such as maintenance, resurfacing and rehabilitation. For a lower IRI limit economical and acceptable maintenance strategy may be selected among a number of maintenance alternatives. The Highway Development and Management (HDM-4) tool can do such measures to help decide which option is the best by evaluating the economic and structural conditions. This paper specifically addresses flexible pavement, including two principal arterial streets under the administration of the Addis Ababa City Roads Authority. The roads include the road from Megenagna Interchange to Ayat Square and from Ayat Square to Tafo RA. First, it was assessed the procedures followed by the city's road authority to develop the appropriate road maintenance strategies. Questionnaire surveys and interviews are used to collect information from the city's road maintenance departments. Second, the project analysis was performed for functional and economic comparison of different maintenance alternatives using HDM-4.

Keywords: appropriate maintenance strategy, cost stream, road deterioration, maintenance alternative

Procedia PDF Downloads 25