Subgrade CBR Research Articles

Numerical Simulation of the Effect of Variation in Subgrade CBR Values on Rigid Pavement

This study presents the results of research on the stress behavior of rigid pavement concrete slabs by varying CBR subgrade values. It aims to know the effect of changing the rigid pavement strss. Data used in this study are geometric data and material properties of the pavement structure. The load vehicle considered is National Road class standard. Rigid pavement is very sensitive with un-uniformity of underlaying supposrt. In this research, the effect of un-uniform support of subgrade was modeled numerically using Abaqus software. The friction coefficient of each layer was also considered in the model. Model simulation of existing rigid pavement calculated 13 variations of CBR values. Result shown that there is a stress increment by 26.27% in the longitudinal direction of the rigid pavement between models with uniform variations of CBR and models with non-uniform variations of CBR. This result show the sensitivity of rigid pavement to un-uniformity of subgrade.

Runway Pavement Design using the Federal Aviation Administration Method

Dhoho International Airport is a new airport located in Kediri Regency, East Java Province, which is built on an area of + 454.5 hectares with a runway length of 3300 m and a width of 45 m. According to its hierarchy, Dhoho Kediri International Airport is a feeder airport (spoke). The B777-300ER aircraft is planned to operate at Dhoho International Airport with a plan life of 10 years which has a subgrade CBR value of 6%. The purpose of this research is to determine the thickness of flexible pavement on the runway of Dhoho Kediri International Airport using the FAA method. In determining the thickness of the runway flexible pavement using the FAA method is influenced by the number of annual departures of aircraft, the MTOW value of aircraft and the CBR value of the subgrade. To determine the annual number of aircraft departures at the new airport, it is necessary to forecast the number of passengers by considering the number of passengers at the nearest airport. Based on data analysis in this study, the total thickness of runway flexible pavement at Dhoho International Airport using FAA method is 102 cm with details of surface thickness of 13 cm, base course thickness of 56 cm, and subbase thickness of 33 cm.

Improvement of Subgrade CBR Using Geotextile

The main purpose of our project is to test the improvement in the CALIFORNIA BEARIBG RATIO of SUBGRADE SOIL upon usage of GEOTEXTILE layer in the soil. We planned to test the effect of geotextile under different conditions of placement height, soil characterstics and moisture content. We performed experiments in the laboratory to determine the results and variation of CBR value and plotted it to draw inferences. Key Words: CBR, Geotextile, Subgrade, Moisture Content, Silty soil, Sandy soil.

PLANNING OF FLEXIBLE PAVEMENT THICKNESS FOR NEW RUNWAY IN SUPADIO INTERNATIONAL AIRPORT WITH FEDERAL AVIATION ADMINISTRATION METHOD

The runway is one component in the airport system, its performance greatly affectsall airport operational activities. Anticipating the increase in services from thecapacity of the number of passengers, it is necessary to build a new runway. In thisstudy, analyze the forecast of the number of movements with the trend analysismethod and the percent forecast method from PT. Angkasa Pura II, field subgradeCBR, new runway capacity and planning year, and new runway pavement using theFederal Aviation Administration (FAA) method and FAARFIELD 1.42 software.Based on the analysis results, the field subgrade CBR was 0.38% < 3%, then it wasstabilized using selected soil (CBR 20.523%) with a thickness of 60 cm. The forecastresults with both methods show that the trend analysis method is used because thetime is earlier than other methods, namely in 2027 with the existing runway capacityat Supadio International Airport of 54 operations/hour with a maximum capacity of51 operations/hour. The results of the runway flexible pavement thickness using theFAA method manually obtained a total pavement thickness of 42” (107 cm), whichconsists of 4”(10 cm) Surface Course, 12”(31 cm) Base Course, and 26”(66 cm)Subbase Course, while the FAARFIELD 1.42 software has a total pavementthickness of 30.43”(77 cm), which consists of 4”(10 cm) Surface Course, 5” (13 cm)Base Course, and 21.43”(54 cm) Subbase Courses.

PLANNING OF FLEXIBLE PAVEMENT THICKNESS FOR NEW RUNWAY IN SUPADIO INTERNATIONAL AIRPORT WITH FEDERAL AVIATION ADMINISTRATION METHOD

The runway is one component in the airport system, its performance greatly affectsall airport operational activities. Anticipating the increase in services from thecapacity of the number of passengers, it is necessary to build a new runway. In thisstudy, analyze the forecast of the number of movements with the trend analysismethod and the percent forecast method from PT. Angkasa Pura II, field subgradeCBR, new runway capacity and planning year, and new runway pavement using theFederal Aviation Administration (FAA) method and FAARFIELD 1.42 software.Based on the analysis results, the field subgrade CBR was 0.38% < 3%, then it wasstabilized using selected soil (CBR 20.523%) with a thickness of 60 cm. The forecastresults with both methods show that the trend analysis method is used because thetime is earlier than other methods, namely in 2027 with the existing runway capacityat Supadio International Airport of 54 operations/hour with a maximum capacity of51 operations/hour. The results of the runway flexible pavement thickness using theFAA method manually obtained a total pavement thickness of 42” (107 cm), whichconsists of 4”(10 cm) Surface Course, 12”(31 cm) Base Course, and 26”(66 cm)Subbase Course, while the FAARFIELD 1.42 software has a total pavementthickness of 30.43”(77 cm), which consists of 4”(10 cm) Surface Course, 5” (13 cm)Base Course, and 21.43”(54 cm) Subbase Courses.

Analisa Perkerasan Kaku (Rigid Pavement) pada Ruas Jalan Simpang Pudak – Suak Kandis Kabupaten Muaro Jambi

The Simpang Pudak road section is a district road that connects Muaro Jambi with Jambi City. This road section is a link to the economic, social and cultural sectors of Muaro Jambi Regency and Jambi City, so that there are also factory vehicles crossing the Simpang Pudak road section, dominated by small and large trucks transporting economic products and other agricultural products. The condition of the Simpang Pudak Road is a flexible pavement that has destroyed its surface to the foundation layer below it. he purpose of this study is to analyze rigid pavement using the 1993 AASHTO method. Planning with a road length of 312.9 m and a width of 7 meters, with a subgrade CBR of 7.3%, with a W18 value in a year of 455,664,051. In this study, the ESAL value in 30 years was 24,814,115,134 ESAL, with a concrete slab thickness of 27.2 cm. With a continuous type of pavement connection with reinforcement with a plate length of 5.5 meters, M10–150 mm wiremesh reinforcement is installed. As well as installed Tie Bar reinforcement 16 mm with a length of 700 mm and a distance of 750 mm. As well as 32 mm Dowel reinforcement with a length of 450 mm and a distance of 300 mm.

EVALUASI PERENCANAAN PEMBANGUNAN JALAN MUARA SIBERUT KE DESA MALILIMO (STA. 00+000 S/D 13+000) KECAMATAN SIBERUT SELATAN KEPULAUAN MENTAWAI

The construction of a road connecting Muara Siberut Village and Malilimo Village located in the South Siberut District of the Mentawai Islands aims to facilitate transportation flows, connect and open up isolation between 2 regions, namely Muaro Siberut Village and Malilimo Village for the advancement of an area and economic equality. In planning the construction of highways in this writing, it refers to the Geometric planning procedures for Inter-City Roads in 1997 and the Regulations on Geometric Planning for Highways in 1970 issued by the Public Works Service of the Directorate General of Highways. The type of road from Muaro Siberut Village to Malilimo Village is a collector road with class IIA road specifications, pavement width of 2 x 3.5m, planned 22 SCS (Spiral-Circle-Spiral) bends, and 6 FC (Full Circle) bends. (concrete) from Muara Siberut Village to Malilimo Village using rigid concrete pavement types, including: compressive tensile strength of concrete fcf aged 28 days 3.36 Mpa, under foundation CBK (mixed thin concrete) 125 mm, subgrade CBR 3,043 % . 170 mm thick concrete slabKeywords: Geometry Planning Bend S-C-S (Spiral-Circle-Spiral) andf-C (Full Circle), Thickness of Pavement

Runway Pavement Strength Evaluation of Yogyakarta International Airports Depends on ICAO (ACN/PCN) Method with COMFAA 3.0 Software

Yogyakarta International Airport (YIA) is a new airport which serves as an international transit station for Yogyakarta and surrounding areas. The airport was designed to serve large and heavy aircrafts with relatively high frequency. To meet flight safety standards,the runway must be designed to be able withstand the wheel weight of aircrafts to be served by the airport. The study aims to determine the thickness and strength of the runway pavement using the FAA method (Federal Aviation Administration) and COMFAA software. The reference aircraft used was Boeing 747-400ER based on landing wheel configuration. With a subgrade CBR value of 6%, Aircraft Classification Number (ACN) and Pavement Classification Number values of 77.8 and 94.9, respectively, were obtained. PCNvalue higher than ACN value indicates that the pavement structure condition is able to withstand the weight of all aircraft types that are planned to be served by the runway of YIA.

Design and development of methodology for construction of thin white topping for rural roads in India

A large proportion of villages in India have been connected with water bound macadam (WBM) or bituminous roads. Rural roads usually have a low volume of traffic, consisting mostly of light transport vehicles with less frequency of heavy traffic. Maintenance of these roads is neglected because of the paucity of funds and the created road asset is in deteriorated condition. The non-availability of suitable soil and aggregates has made projects unviable and cost prohibitive. This aggregate scarcity will increase further as a result of environmental conservation and restriction on mining. There is a need to develop alternative pavement designs to construct sustainable and durable rural roads. The stabilization of soil/aggregate is being used worldwide towards optimal usage of scarce resources. The concepts of soil/aggregate stabilization and Cold In Place Recycling technique provide a comprehensive solution for rehabilitation of existing road and greenfield road construction. Cold In Place Recycling process allows usage of locally available marginal materials. The stabilization process can use a wide range of stabilization agents such as soil-aggregate mix, lime, cement, fly ash, foamed bitumen, emulsion, polymers, and other proprietary chemical stabilizers. Two rural roads are identified under Mukhya Mantri Gram Sadak Yojana Research and Development Scheme. Pavements are designed considering cement treated base. These roads are constructed using the Cold In Place Recycling technique. The existing water bound macadam (WBM)/deteriorated bituminous surface is stabilized with cement. Bituminous concrete and Thin White Topping are provided as wearing course. The performance of pavement is evaluated after 2 years of construction. Also, the balance life of the pavement is checked and the results are satisfactory. The stabilized pavements offer superior strength and longevity, even in extreme climatic conditions, and provide better performance. The design charts for Thin White Topping for rural roads are not available, hence the design charts for Thin White Topping of M30/M35/M40 grade concrete on Cement Treated Base of varying thickness and different subgrade CBR are prepared based on IRC 62-2014 for traffic less than 50 CVPD, 51 to 150 CVPD, and less than 450 CVPD. These charts are ready to use and act as a guide to the Field Engineers. The optimum thickness of Thin White Topping can be selected from the chart for known subgrade CBR and Traffic. The effect of variation of CTB thickness on Thin White Topping thickness can be determined from the chart.

COMPARATIVE STUDY OF RIGID PAVEMENT PLANNING USING BINA MARGA 2017 AND AASHTO 1993 METHODS

This study was conducted to determine what factors influence the differences in the results of the Bina Marga 2017 method and the AASHTO 1993 method and determine which planning results are more efficient to be applied to Letjen S. Parman Street. The research method used is a comparative method, using the existing data and the latest data from surveys. As a result of analyzing a rigid road plan with a planned age of 40 years, the Bina Marga 2017 method obtained a concrete slab with a thickness of 305 mm, and the AASHTO 1993 method obtained a concrete slab with a thickness of 280 mm. Further differences in results can be seen in the level of traffic load during the service life, the diameter of the dowels, the spacing of the tie bars, and the minimum design height of the subgrade embankment. The differences in the results of these plans are caused by two main factors, namely the factor of using the cumulative traffic growth value (R) in the Bina Marga 2017 method and the direct use of the subgrade CBR value in the AASHTO 1993 method. Based on the data that has been obtained, it is concluded that the 1993 AASHTO method provides more efficient results to be applied with considerations in terms of smaller plate dimensions and fewer connections and reinforcement requirements. Which when calculating the work cost, the AASHTO 1993 methods results give a smaller number of work volumes, so it has the possibility to provide a more economical work cost than the Bina Marga 2017 methods results.

Thickness Analysis of Runway Pavement Construction at Zainuddin Abdul Madjid Airport to Accommodate Boeing 777-300ER

Lombok Island is one of destinations for travel from various regions due to construction of a racing circuit on the island. Large events such as MotoGP, GT World Challenge Asia, World Superbike,and others will often be held, so that it will increase tourists to visit Lombok Island. With this increase, it is necessary to develop facilities of Zainuddin Abdul Madjid Airport. One of them is runway pavement must have a thick layer that is able to accommodate aircraft movement activities. Zainuddin Abdul Madjid Airport is planned to be able to facilitate larger planned aircraft, that is B777-300ER. The increase in facilities needed is the extension of the runway with pavement structure which needs to be adjusted to the aircraft load that will be received by the pavement. Based on this, the runway pavement construction structure at Zainuddin Abdul Madjid Airport will be designed using FAA method with FAARFIELD software and PCN value was calculated using the COMFAA software. The data needed are annual departure, subgrade CBR,and type of pavement layer used. From the calculation results, the pavement thickness for the runway extension is Surface P-401/P-403 thickness is 100 mm thick, P-401/P-403 Stabilized thickness is 127 mm thick, and Crushed Aggregate P-209 thickness is 296mm. The PCN value for runway extension is 71/F/A/X/T.

Perbandingan Perencanaan Tebal Perkerasan Jalan Paving Block Metoda Analisa Komponen (MAK) 1987 dengan MAK 2002

Concrete blocks are an alternative surface coating for road construction made of a mixture of cement, filler and water. The road that will be redesigned with pavement thickness is the DR. Moh. Hatta section of Pasar Baru - Gate of Unand Padang. This road has an uphill contour so that conventional roads are unable to withstand the flow of water falling down, causing puddles that can damage the road construction. Pavement thickness planning for paving block roads on Jalan DR. Moh. Hatta Padang uses the 1987 component analysis method and the 2002 component analysis method by entering the road planning parameters: the carrying capacity of the soil is obtained from the CBR value of the subgrade, the traffic load is obtained from the average daily traffic. With a subgrade CBR of 5.25%, 8 cm thick paving blocks with K-300 quality, 100% CBR crushed stone foundation layer, and 70% CBR gravel bottom foundation layer. So from the 1987CAM results obtained a surface layer with a thickness of 8 cm, 10 cm lean concrete, 15 cm top foundation layer, and 10 cm bottom foundation layer. While 2002 CAM obtained a surface layer of 8 cm thick, 10 cm of lean concrete, 10 cm of top foundation layer, and 10 cm of bottom foundation layer.

An experimental study on fly ash with lime and gypsum for quality improvement in pavement subgrade materials

Characteristics of pavement subgrade materials play a paramount role in determining the quality and longevity of a pavement. An experimental study has been undertaken to improve such subgrade material on addition of fly ash (percentage of addition 9.7–30%) as main additive. Two broad sets of samples have been mixed with varying proportions of moorum, silver sand, fly ash mix with stabilizer, i.e. lime and gypsum (percentage of addition from 2 to 3%) for one set, and another set of samples where it consists of moorum, silver sand and soil mix (percentage of addition 10–30%) without fly ash and stabilizer. For each set of sample, the main broad constituent materials have been taken as moorum and silver sand which have percentage of variations 47.53–70% and 20.37–30%, respectively, because they are the main constituents for pavement subgrade material. To investigate the effects of addition of these stabilizers to assess whether it improves the performance of pavement subgrade materials Proctor tests, CBR and UCS tests have been done on both types of soil samples. The test results have shown that lateritic soil like moorum with silver sand used with addition of stabilizer as a sub-base materials of pavement can be used as a better replacement of commonly used graded traditional coarse aggregate and fly ash used as fines has shown better replacement of local soil. A high correlation coefficient indicates that the CBR value can be well predicted from UCS test results.

Full-Scale Evaluation of Relatively Thin Airfield Pavements

A full-scale airfield pavement test section was constructed and trafficked by the U.S. Army Engineer Research and Development Center (ERDC) to evaluate the performance of relatively thin airfield pavement structures. The test section consisted of four test items that included three asphalt pavement thicknesses and two different aggregate base courses. The test items were subjected to simulated aircraft traffic to evaluate their response and performance to realistic aircraft loads. Rutting behavior, instrumentation response, and falling weight deflectometer response were monitored at selected traffic intervals. It was found that the performance of the airfield pavement sections were most sensitive to aggregate base course properties, where a 50% reduction in base course strength resulted in a 99% reduction in allowable passes. The data suggested that when sufficient asphalt thickness is not provided, the failure mechanism shifted from subgrade failure to base course failure, particularly at higher subgrade CBR values. In addition, the number of aircraft passes sustained was less than that predicted by current Department of Defense (DOD) methods that include assumptions of a high-quality aggregate base and a minimum asphalt concrete thickness. The results of this study were used to extend existing DOD pavement design and evaluation techniques to include the evaluation of airfield pavement sections that do not meet the current criteria for aggregate base quality and minimum asphalt concrete surface thickness. These performance data were used to develop a new base failure design curve using existing stress-based design criteria.

Effect of Modulus of Bituminous Layers and Utilization of Capping Layer on Weak Pavement Subgrades

The majority of the world’s highways consist of a flexible pavement commonly built of several layers (both asphaltic and granular) that have been laid over a pavement foundation known as the subgrade. A subgrade that is considered to be of a satisfying bearing capacity is expected to restrict not only the immediate distresses occurring during the construction phases, but also later deformations appearing during the service life of the pavement as it subjected to traffic loads. If the subgrade proves to be structurally weak, the highway’s flexible pavement can be supported by adding such modifications as a capping layer, which serves to greatly reduce the stress being applied to the pavement. This study aims to further our knowledge about maximum pavement functionality by investigating those parameters considered crucial to pavement design: the correspondence of material properties, the number of layers, and the layer thickness. These parameters were analyzed to determine the best performing composition, while also considering the financial aspects of road construction. To achieve such an aim, we chose to use KENLAYER software to assist us in determining the design of a flexible pavement in line with a specific Equivalent Single Axle Load (ESAL). The KENLAYER configuration provided us with the required ESAL targets for specific design lives. We next calculated the relative costs of these targets and chose those that proved to be most cost-effective and economical. The results indicate that when considering feasible pavements to meet a design of high ESAL applications, those utilizing high modulus asphaltic materials are most suitable for subgrade CBR of at least 3%, while weaker subgrade constructions must be provided with a capping layer.

Cement Soil Stabilization as an Improvement Technique for Rail Track Subgrade, and Highway Subbase and Base Courses: A Review

This research paper summarizes published research works on the suitability of cement as an effective chemical stabilizer to improve the strength and durability requirements of sand to be used as subgrade and base courses for rail track and road construction respectively. Advantages and problems associated with soil stabilization using chemicals have also been briefly discussed in this report. It has been confirmed that ordinary Portland cement is an effective chemical stabilizer to improve both the index and strength properties of soils, however, the optima percentage of cement contents are varied from a soil type to another. In addition, further research has to be carried out as the percentage of cement content varies from region to region and from soil characteristics to another. This is necessary so as to determine the optimum percentage of cement content that would yield the desired subgrade CBR values with some other index properties to meet the specified requirements in any selected design manual.

Optimization of Cost and Time of Repair and Rounding of Roads With Way Pavement Design Manual Method 2013

Smoothness, safety, and comfort of traffic depend on road pavement conditions. If the width of the road is narrow, damaged, hollow, the traffic will disrupted; the travel time will increase, fuel consumption increases, the risk of damage to high vehicles and so on, if there is no immediate improvement in the form of an increase, the damage will increase. To deal with this problem, it is necessary to research and plan road improvements with widening, an increase in existing pavements with overlays, the need for cost and time of implementation. The Mojokerto - Ploso road segment is an alternative route connecting the cities of Mojokerto - Jombang, and Lamongan. Based on the status of the road is the provincial road, and based on the function is the Collector’s road. Furthermore, for the planning of improvement and widening required subgrade CBR data, for overlay planning, a Test Pit data is needed to determine the existing pavement structure and traffic data. In determining the road widening plan, the 2015 revised Road Pavement Design Manual (MDP) method for overlaying was used with the Planning Guidelines for Pt-T-01-2002-B Bending Pavement Thickness and calculating the Budget using Work Unit Price Analysis (AHSP ) 2013, creating a Schedule of Work (Time Schedule), as well as calculating the critical path to find out the critical path in carrying out the work. To planning data analysis is needed - traffic data, land investigation, layer thickness calculation on widening, overlay layer thickness, cost requirements, execution time and critical track path. From the calculation results, the road widening obtained AC = 5 cm pavement arrangement, ATB = 14 cm, CTB = 30 cm, Class B Aggregate = 20 cm, the optional load support layer = 85 cm, using geogrid as the selected urine separator with subgrade, in the old pavement repair (overlay) with an overlay, the AC = 5 cm arrangement, ATB = 14 cm, at a cost of Rp. 19,200,000,000.00 (Nineteen billion two hundred million rupiahs) with a 20-year plan life, as well as a 6-month implementation time.

Data Processing, Storage, and Analysis: Applying Computational Procedures to the Case of a Falling Weight Deflectomer (FWD)

In the field of civil engineering, the adoption and use of Falling Weight Deflectometers (FWDs) is seen as a response to the ever changing and technology-driven world. Specifically, FWDs refer to devices that aid in evaluating the physical properties of a pavement. This paper has assessed the concepts of data processing, storage, and analysis via FWDs. The device has been found to play an important role in enabling the operators and field practitioners to understand vertical deflection responses upon subjecting pavements to impulse loads. In turn, the resultant data and its analysis outcomes lead to the backcalculation of the state of stiffness, with initial analyses of the deflection bowl occurring in conjunction with the measured or assumed layer thicknesses. In turn, outcomes from the backcalculation processes lead to the understanding of the nature of the strains, stresses, and moduli in the individual layers; besides layer thickness sensitivity, the determination of isotropic layer moduli, and establishing estimates in the subgrade CBR. Overall, impositions of elastic and low strain conditions foster the determination of resilient modulus and the analysis of unbound granular materials. Hence, FWD data processing, analysis, and storage gain significance in civil engineering because it informs the nature of designing new pavements and other rehabilitation design options.

True triaxial testing of geogrid for high speed railways

Abstract This work describes a series of novel experimental tests to determine the potential of geogrids to confine granular layers within ballasted railway lines operating at speeds close to critical velocity. This is important because at low train speeds, vertical stresses are dominant, but when approaching critical velocity conditions, dynamic horizontal stress levels are magnified. Therefore the majority of previous geogrid investigations have been performed assuming constant horizontal stress levels, thus making them more relevant for lower speed lines. To investigate settlement under high relative train speeds, ballasted railway track samples were subject to combined vertical-horizontal cyclic loading. Three areas were explored: (1) the performance benefit from placing geogrid at the ballast-subballast interface, (2) the performance benefit from placing geogrid at the subballast-subgrade interface, (3) the effect of subgrade stiffness on geogrid performance at the subballast-subgrade interface. Testing was performed using a unique large-scale true triaxial apparatus which had the ability to vary stress levels in three Cartesian directions. Compared to the control conditions, the geogrid offered a settlement improvement of approximately 35% when placed at the ballast-subballast interface, and 10–15% when placed at the subballast-subgrade interface. Regarding subgrade CBR, it was found that the geogrid offered the greatest performance benefits when the subgrade was soft. Therefore it was concluded that for the ballasted rail structures under test, when subject to elevated levels of horizontal stress, geogrids reduced settlements compared to non-geogrid solutions.

Towards innovative design and construction standards for lime stabilised subgrades

Recycling of existing and virgin pavement materials has been carried out successfully in Malaysia since the 1980’s using the process of Insitu Stabilisation. The majority of specified works have been completed using General Purpose cement as the binding agent for use in granular base and sub base materials. The use of lime is becoming more popular in Malaysia as asset owners realise the importance of creating sound platforms to build upon with pavement structures. In pavement design, the two most critical inputs that influence the overall thickness of a pavement structure are the traffic loadings and the design subgrade CBR. Subgrade stiffness is the controlling variable that can be designed for improvement and should be enhanced wherever possible. Lime is particularly suited to dramatically improve the bearing capacity, reduce the volumetric instability and decrease the moisture susceptibility of clayey, expansive and plastic materials which are commonly encountered in pavement subgrades. Due to a current lack of design methodologies and construction specifications in Malaysia incorporating lime stabilised materials, this paper will explore the influencing factors for design of lime stabilised subgrades with an emphasis on thickness design and mix design parameters.