1,720,979 research outputs found
Effect of Copper Slag in Subgrade Soil for Design of Flexible Runway Pavement
No full textMaster of Engineering- InfrastructurePreparation of subgrade for a transportation infrastructure on a problematic soil like clayey
soil has always been a matter of great concern as clay can exhibit geotechnical problems like
high compressibility, high plasticity, high swelling and shrinkage properties etc. To solve
these problems and to improve the quality of soil, various soil stabilisation methods can be
used. In our study, the properties of the clayey soil is improved by mixing the soil with
industrial wastes like copper slag. Use of copper slag is done as it is way more cost effective
and eco friendly options than others. The copper slag was collected from SYNCO industries,
Jodhpur, Rajasthan and it was used to investigate the effect on locally available soil from
Rajpura, Patiala, Punjab. Various proportions of copper slag (10%, 20%, 30%, 40%, 50%,
60% by weight of the parent soil) was used. The strength of the soil was observed by
performing compaction tests, CBR tests etc. The observation of CBR tests explored that the
CBR of the soil increases with increase in percentage of copper soil and hence the mix can be
successfully used as a subgrade for flexible pavement for airport. FAARFEILD computer
program is used to determine the pavement layer thickness
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Investigating the Performance of Geocell Reinforced Unbound Layer Using Light Weight Deflectometer
No full textRapid road infrastructure construction has become a trend in India and around the world. Many road projects have necessitated early-stage maintenance during the last few decades. To figure out what's causing it, a structural evaluation study is needed to analyze the existing material qualities of the pavement. Many studies have evaluated flexible pavements using widely used NDT technologies such as LWD, BBD, and FWD. While LWD is gaining acceptance and popularity as an in-situ spot-testing device all over the world, only a few studies have been done and are necessary to be carried out in India in order to make the use of the LWD technique beneficial in road repair projects. The primary objective of this research is to use LWD to estimate the subbase surface and subgrade modulus of the unreinforced and reinforced sections and to provide rehabilitation options based on the LWD results. The lightweight deflectometer (LWD) is a highly advanced and sophisticated device that was developed to evaluate the deformation modulus (Esub LWD) of compacted geomaterials as an alternative density test.
One of the ground improvement techniques rapidly expanding is geosynthetic soil reinforcement, primarily due to cost-effectiveness, simplicity, and ease of construction. The most recent development in the field of geosynthetics soil reinforcement is the use of geocells at the base and subbase courses of the pavement systems. Geocells improve pavement performance while also attaining sustainable goals, as shown by research, testing, field trails, and case studies. This research aimed to figure out what causes improved bearing capacity and what benefits geocells deliver. Geocell was used in this study in a variety of layouts and sizes with gradation (Grade I as per MoRTH for both Laboratory and Field Evaluations. It was also discovered that the best performance is achieved when a geocell of height 125 mm layer is installed in the unbound layer.
The performance improvement was presented in terms of Modulus Improvement Factor (MIF). This study intends to use the LWD device and present the ranges of deformation modulus for various geomaterials from several studies. For instance, in the case of soils and aggregates, deformation modulus values were found to be in the range of 35-60 MPa and 80-120 MPa, respectively. In addition, several studies have been compiled to completely comprehend the relationship between LWD and various geocell layouts. In addition to the cost savings, this would
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conserve natural materials like aggregates used in pavement construction. Overall, the inclusion of geocell in the subbase layer helps improve the life, uniform distribution of load and provides an economical and sustainable solution to the present practices.
Finite Element Analyses (FEA) were used in the investigation, and the results were confirmed through laboratory tests. The objective is to understand the behavior of unpaved roads with unreinforced and geocell-reinforced subbase. Based on FEA and laboratory evaluation, the study investigated that the geocells are beneficial when construction is performed with a lower/marginal subbase and subgrade material. The geocells allow placement on top of the weak quality subgrade
Effect of the Position of Geotextile on the Strength Characteristics of Subgrade in Bituminous Pavements
No full textMaster of Engineering-Infrastructures EngineeringIn the past 20 years, many new road improvement techniques have revolved around
the use of geosynthetics. In India, most of the flexible pavements are need to be
constructed over weak sub-grade having low modulus values. The California bearing
ratio (CBR) of these sub-grade soils has very low, resulting in more thickness of the
road crust. Replacing of these existing weak subgrade soil may not be good option,
thus it is required to stabilize these weak subgrade soil with suitable stabilizer.
Geosynthetics have been found to be a cost effective alternative to improve the weak
subgrade soils in adverse locations. In this study, firstly the various properties of soil
sample like grain size analysis, liquid limit, plastic limit, plasticity index &
identification of soil has been evaluated and then CBR values of these soils have been
improved using geotextiles. Non-Woven geotextiles are placed at different layers of
various soil samples, and then a series of California Bearing Ratio (CBR) tests were
conducted to evaluate the strength of the subgrade soil. It was observed that the CBR
value increases, when the non-woven geotextile are placed at different layers of
various soil sample. From this study, single layer of non-woven geotextiles is
introduced at the depth of 0.85H from the bottom of the mould shows better
performance than those samples with the geotextiles layer are placed at other depths.
In this study, the flexible pavement have been designed for both fatigue and rutting
life of 100MSA at 90% and 80% reliability, when the non-woven geotextile are
placed at three different depths of subgrade soil samples. The critical strain value for
both fatigue and rutting life are analysed by programme IITPAVE software and are
less than the allowable strain values as computed by IRC: 37-2012
Laboratory Investigation and Field Performance Evaluation for Chemically Stabilized Cement Treated Sub-Bases
No full textIndia is making significant investments in the transportation sector, but in many locations, the
procurement and the processing cost of naturally available materials is exorbitantly
increasing because of rapid depletion of these materials. In this work, soil that is readily
available in the area, cement and nano-chemicals like Terracil and Zycobond are utilised to
assess the impact of nano materials on California bearing ratio and compressive strength of
chemically treated sub-base layer. XRD, SEM tests were carried out to identify the micro
structure of different mixes. The addition of optimum dosage of nanoparticles had a very
advantageous effect on UCS and CBR. The compressive strength of the soil aggregate mix
treated with cement was improved by up to 103.4% by the addition of nano compounds. The
California bearing ratio of the mix treated with optimum dosage of cement and chemical was
increased by 219%. The different laboratory prepared mix were laid on the field
(Intermediate lane, PMGSY road) to study a behaviour of mix. To examine the deflection
and modulus for various mixes laid on the field, a deflectometric investigation employing a
lightweight deflectometer was conducted. LWD was also used to calculate the 28-day
modulus.
SEM, XRD analysis depicted that the nanoparticles promoted the pozzolanic reaction by
transforming portlandite into C-S-H gel. According to the X-ray diffraction patterns,
stabilisation by terrasil and zycobond results in the creation of additional peaks like CSH and
changes the structure of pure soil when gypsum is added. SEM pictures of soil samples
reveal a denser texture as a result of chemical stabilisation and a decline in the Si/Al ratio,
which suggests increased shear strength in stabilised samples according to interpretation of
energy dispersive X-rays (EDS)
Laboratory Investigation of Cement Treated Bases (CTB) and Full-depth Reclamation (FDR) Mixes.
No full textIn the last decades, new road melioration technologies have evolved to abate the utilization of
aggregates in new pavement, this helps in abating the construction cost, decimation of natural
resources as well as curtailing of energy. This study provides an innovative approach to
determining the per cent of cement added for the base course stabilisation along with the certain
percentage of class C fly ash and to study the engineering properties of the stabilized mix. Also,
with the application of FDR, an effective approach was made to improve the strength of
reclaimed pavement material (RPM) by the utilization of TerraCil & ZycoBond, chemical
commercial stabilizers along with a certain percentage of cement to reduce moisture damage
(water permeability) and enhance the flexibility enabling dimensionally stable non-deforming
base. Due to the use of various cement percentages and chemical stabilisers in the case of FDR,
aspects related to compaction, durability, and unconfined compressive strength (UCS) are
examined. The UCS increased substantially with the addition of different cement per cent in
the CTB mix but decreases on increasing fly ash content and stabilizers along with cement in
FDR. There was an average mass loss of 5.80% in 12 cycles of wetting-drying have been
observed in the durability test of the CTB mix designed.
This study shows how it is beneficial to use the cement-treated base to replace the conventional
base material used for the construction of high-volume and low volume-roads. According to
the analysis of the sections that were designed, a thicker wearing course is needed because the
granular layer's strength is poor in order to prevent roads from failing due to rutting and
cracking. There is a significant difference in the cost of construction of wearing course and
other layers of flexible pavement. Due to the higher modulus of Cement Treated Base (CTB),
the thickness of CTB is significantly less than Granular Base (GSB) layer for same traffic
count. CTB is the better alternative to conventional granular base. So, an attempt has been
made to investigate the cost of the construction of flexible pavement designed with CTB as a
base layer for 50 msa traffic for high-volume roads and 5 msa traffic for low-volume roads.
IRC: 37 (2018) was followed to estimate the thickness of different layers of flexible pavement.
The cost per kilometre of a road having a flexible pavement designed with CTB base layer was
reduced by 24.48% for high-volume roads and 34.20 % for low-volume ones. Further, with the
application of FDR, a cost reduction of 30.06% was indicated in the low-volume roads
Correlation of CBR with Index Properties of Soil
No full textME, CEDCalifornia bearing ratio is most used indirect method to assess the stiffness modulus and shear strength of subgrade in the design of flexible pavement. The type of soil not only affects the CBR value, but the CBR value also varies with different properties possessed by the soil. CBR value of soil depends on many factors like maximum dry density (MDD), optimum moisture content (OMC), liquid limit (LL), unconfined compressive strength, percent fines etc. Determination of CBR is a bit lengthy and time consuming process.
In this study, soil samples were taken from 11 different locations within 50 km radius of Patiala city and various tests were performed on these sample. An attempt has been made to correlate soaked as well as unsoaked CBR value with percent fines, LL, MDD and OMC. ANN model is also developed to established best linear fit between the experimental values and the literature value.
The correlation is established in the form of an equation of CBR as a function of different soil properties by the method of regression analysis. It has been observed that the predicted values are in the domain of experimental values and the results indicated a strong correlation with value of r2=0.901 for unsoaked CBR and r2= 0.897 for soaked CBR.CE
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