FROST SUSCEPTIBILITY OF MASSACHUSETTS SOILS-EVALUATION OF RAID FROST SUSCEPTIBILITY TESTS

Two promising approaches to the development of a rapid laboratory procedure for evaluation of frost susceptibility of soils are investigated in detail. Measurement of pore water pressure change during freezing of soil in a closed system under constant temperature gradients is shown to be extremely sensitive to experimental technique so that its usefulness as a rapid routine test is limited. Heave pressure measurement during the freezing of soil in an open system, at essentially constant volume under constant temperature gradients, is shown to be a simpler, faster and less sensitive approach to experimental technique than the pore water pressure approach. The heave pressure method is therefore recommended. Evaluation of frost susceptibility is based upon the characteristics shape of the heave pressure of pore pressure versus log time curves. Once a constant temperature gradient has been established, the characteristic curve shows a straight line segment. The slope and the duration of the straight line segment is used to rate the continued relative frost susceptibility of soils. To effectively apply this laboratory procedure, data must be collected relating results from this test with detailed field frost susceptibility data. /FHWA/