FLOW AND STABILITY LIMITS FOR 6-INCH-DIAMETER MARSHALL SPECIMENS

Finite element analyses were conducted to determine appropriate specif ications for limits on flow and stability of 6-in. (152.4-mm) diameter specimens in the Marshall procedure for mix design of bituminous' con crete. Loads and deformations on 6-in.-diameter specimens were determi ned that result in a state of stress similar to that in 4-in. (101.6-m m) diameter specimens at initiation of yield. From these results, dime nsionless scaling factors were determined by which stability and flow specifications for 4-in.-diameter specimens can be multiplied to deter mine appropriate limits for 6-in.-diameter specimens. These analyses p rovide a more rational basis for evaluation of stresses and deformatio ns that occur in the Marshall test than has been provided previously. The results yielded scaling factors of 1.50 for flow and 2.25 for stab ility, which verify the results of experimental results reported in th e literature.