NONDESTRUCTIVE TESTING
NONDESTRUCTIVE TESTING
While the Benkelman beam was developed for use at the AASHO Road Test (1952), the experience at the AASHO Road Test led to its widespread use subsequently for overlay design purposes for both asphalt and concrete pavements. The International Asphalt Paving Conferences of 1967 and 1972, for example, continued development in this area. The Benkelman beam spurred the development of mechanized versions like the LaCroix deflectograph (France) and traveling deflectometer (Hveem, California). The devices are shown in Figure 14 .
TABLE 2 Examples of Analytically Based Design Procedures for Asphalt Pavements
Organization Pavement
Shell International
Design charts; Petroleum Co., Ltd.,
Multilayer elastic solid
Fatigue in treated layers; rutting:
Temperature AC, untreated
computer program London, England (71)
– Subgrade strain and
aggregate, cement-
BISAR for analysis NCHRP Project 1-10B
– Estimate in asphalt bound layer
stabilized aggregate
Design charts; Procedure (AASHTO)
Multilayer elastic solid
Fatigue in treated layers; rutting
Temperature
AC, asphalt-
computer program (19)
stabilized bases,
(MTC093) AI, Lexington, Ky.
untreated aggregates
AC, asphalt emulsion, Design charts; (MS-1, MS-11, MS-23)
Multilayer elastic solid
Fatigue in asphalt treated layers;
Temperature,
computer program (73,74)
rutting: subgrade strain
freezing and
treated bases,
DAMA Laboratoire Central de
thawing
untreated aggregate
Catalogue of Ponts et Chaussées
Multilayer elastic solid
Fatigue in treated layers; rutting
Temperature
AC, asphalt-treated
designs; computer (LCPC) (75,76 )
bases, cement-
stabilized aggregates, program (ELIZE) untreated aggregates
for analysis Centre de Recherches
Design charts; Routieres, Belgium
Multilayer elastic solid
Fatigue in treated layers; rutting
Temperature
AC, asphalt-
computer program (77)
stabilized bases,
(MTC093) NITRR, South Africa
untreated aggregates
Temperature Gap-graded asphalt Catalogue of (78–80)
Multilayer elastic solid
Fatigue in treated layers; rutting:
– Subgrade strain and
mix, AC, cement-
designs; computer
– Shear in granular layers
stabilized aggregate,
program
untreated aggregate
NCHRP Project 1-26
ILLI-PAVE; elastic Procedure (AASHTO)
Finite element
Fatigue in treated layers; rutting:
Temperature AC, untreated
layer programs (81)
idealization; multilayer
subgrade strain
aggregates
(ELSYM) FHWA, U.S. DOT
elastic solid
Computer program: (82)
Multilayer elastic or
Fatigue in treated layers; rutting:
Temperature AC, cement-
viscoelastic solid
– Estimate at surface and
stabilized aggregate,
VESYS
– Serviceability (as measured by
untreated aggregate,
PSI)
sulphur-treated materials
University of
Temperature Continuous or gap- Design charts; Nottingham, U.K. (83)
Multilayer elastic solid
Fatigue in treated layers; rutting:
subgrade strain
graded asphalt mixes computer program of known volumetrics (ANPAD) for on standard UK
analysis and design
materials
50 Pavement Lessons Learned from the AASHO Road Test and Performance of the Interstate Highway System
(a) (b)
FIGURE 13 Engineers associated with development of M-E design procedures for rigid pavements: (a) P. Fordyce, PCA, and (b) M. I. Darter, University of Illinois.
The Shell researchers used vibratory testing equipment at the Road Test (Nijboer) to measure in situ material response (e.g., moduli). Following the Road Test equipment such as the Dynafleet (Texas, F. Scrivener), vibrators to measure wave propagation (Transport and Road Research Laboratory) and eventually the falling weight deflector (FWD) (France, Denmark) were developed.
Pavement profile equipment was introduced for use at the Road Test (CHLOE Profilometer) and served as an important measure to quantify the present serviceability index (PSI) (Carey and Eirich) to define pavement performance. This equipment stimulated research on pavement smoothness and roughness that resulted in equipment such as the GMR Profilometer (1962 International Asphalt Conference) as well as other equipment worldwide.