ASSESSMENT SUBGRADE SOILS THROUGH CALIFORNIA BEARING RATIO (CBR) ON GILGIT-SKARDU ROAD (PAKISTAN): TECHNIQUES FOR IMPROVEMENT OF SUBGRADE SOIL PROPERTIES

Quality and stiffness of subgrade soils play a crucial part in performance of the pavements subjected to overwhelming traffic stack. To evaluate the quality of road subgrades, a test known as California Bearing Ratio (CBR) was developed by California State Highways Department. CBR is regularly utili...

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Bibliographic Details
Published inI-Manager's Journal on Civil Engineering Vol. 10; no. 2; p. 1
Main Authors MUHAMMAD, BILAL SADIQ, SYED, HUSNAIN ALI SHAH, ABDULLAH, KHAN, ANEEL, AHMED
Format Journal Article
LanguageEnglish
Published Nagercoil iManager Publications 01.03.2020
Subjects
Airports
Atterberg limits
California bearing ratio
Fly ash
Moisture content
Pavements
Penetration tests
Roads & highways
Soil compaction
Soil moisture
Soil properties
Soil stabilization
Soils
Stiffness
Subgrades
United States > US
Pakistan
California
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Summary:Quality and stiffness of subgrade soils play a crucial part in performance of the pavements subjected to overwhelming traffic stack. To evaluate the quality of road subgrades, a test known as California Bearing Ratio (CBR) was developed by California State Highways Department. CBR is regularly utilized for flexible highway and airport pavements and occasionally for other development purposes to assess the strength of earth materials. To assess the values of CBR, Standard Proctor Compaction, and Moisture Content and Atterberg Limits, the collected subgrade soil samples were taken to the laboratory. Standard test methods of ASTM were followed for carrying out different tests. The CBR of the samples ranges from 4 � 16% and the plasticity index (PI) values extend from 13-17% which demonstrates the expansive behavior of the subgrade soils. The examination of different results portrays that the subgrade soils from the study area are of destitute quality, thus these soils don't qualify to be utilized as subgrade concurring to the National Highway Authority (NHA) specification. From the study, it can be concluded that the performance of the examined material ought to be upgraded for utilization as subgrade. After checking on the financial contemplations, evacuation of the existing subgrade soil upto 0.6m and stabilization with a natural waste material such as granite cutting waste and fly ash etc. has been proposed as a subgrade soil enhancement strategy. The other suggested soil advancement strategy involves the introduction of an additional base layer.
ISSN:2231-1068
2249-0779
DOI:10.26634/jce.10.2.16619