THE USE OF NON DESTRUCTIVE TESTING IN FLEXIBLE PAVEMENT REHABILITATION DESIGN

Non destructive testing (NDT) has long been used to evaluate flexible pavement structures. In general terms, center NDT deflection is often thought of as a direct indicator of bearing capacity. Furthermore, deflection curvature, or the shape of the deflection bowl, is often used to indicate the degree of rigidity of the pavement surface. In other words, the greater the radius of curvature, the more rigid the uppermost materials in the pavement system are. It can be shown that the use of deflections may be greatly enhanced, above and beyond the above-mentioned concepts, or variations thereof, through the following: (1) choose an accurate NDT device which can simulate the effect of traffic loads, to this end, a falling weight deflectometer (FWD) device with A sophisticated matching electronic package is employed. (2) Use layered elastic theory instead of the more empirical indicators mentioned above prior to bearing capacity evaluation. (3) Consider the non-linearity of the unbound materials, in particular in a horizontal direction from the FWD imposed impulse load, i.e., corresponding to where the FWD deflections are actually measured. By fulfilling the above three conditions, then, it can be shown that reliable layered (non-linear) elastic parameters can, in fact, be derived from FWD load-deflection data. This is not accomplished through the use of specific deflection readings nor an approximate mathematical expression of deflection bowl curvature, but rather through the proper use of the whole deflection basin at points along it where the properties of each layer are most influential. In rehabilitation design, the elastic parameters derived through the above method are used in a rational procedure through the use of criteria stresses and strains at critical points in the layered elastic system. These critical values are a function of the expected future magnitude and number of traffic loadings. (a) (TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/8251904803
• Supplemental Notes:
  • Proceedings of a International Symposium on Bearing Capacity of Roads and Airfields, Volume 1, Trondheim, held June 23-25, 1982.
• Corporate Authors:

  Tapir

  Trondheim University, Gloeshaugen
  Trondheim-NTH,   Norway 

  Tapir

  Trondheim University, Gloeshaugen
  Trondheim-NTH,   Norway 
• Authors:
  • Stubstad, R N
• Conference:
  • Proceedings of a International Symposium on Bearing Capacity of Roads and Airfields, Volume 1, Trondheim, held June 23-25, 1982.
• Publication Date: 1982

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 31-41

Subject/Index Terms

• TRT Terms: Bearing capacity; Conferences; Curvature; Deflection; Deflectographs; Driver rehabilitation; Elasticity (Mechanics); Evaluation; Falling weight deflectometers; Flexible pavements; Measurement; Nondestructive tests; Nonlinear systems; Pavement design; Pavement maintenance; Pavement performance; Pavements; Strength of materials; Structural strengthening; Test procedures
• Uncontrolled Terms: Rehabilitation
• Old TRIS Terms: Elastic theory; Layered theories; Pavement deflection
• ITRD Terms: 3085: Bearing capacity; 8525: Conference; 5586: Deflection; 6187: Deflectograph; 2870: Degree of curvature; 5912: Elasticity; 2944: Flexible pavement; 6136: Measurement; 6216: Non destructive testing; 6482: Non linear system; 3055: Pavement design; 3096: Strengthening (pavement); 6288: Test method
• Subject Areas: Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00373179
• Record Type: Publication
• Source Agency: Norwegian Road Research Laboratory
• ISBN: 82-519-0480-3
• Files: ITRD, TRIS
• Created Date: Jun 30 1983 12:00AM