In situ measurement of surface wave velocity using the spectral-analysis-of-surface-waves (sasw) method shows that this type of seismic measurement offers a reliable alternative to conventional penetration resistance and cylinder compression testing for determining the stiffness of portland cement concrete during curing. Both surface wave velocity and penetration resistance exhibit similar rates of increase during the initial stages of curing, suggesting that in situ measurements of wave velocity are potentially useful to assess the degree of curing that has occurred. At later stages of curing, valuesof young's moduli calculated from in situ seismic tests agree well with values of young's moduli from cylinder compression tests for similar curing histories. Advantages of nondestructive and nonintrusive seismic tests like the sasw test are that, unlike penetration resistance and cylinder compression tests, these tests (a) require no samples, (b) can be performed directly on the concrete slab to evaluate spatial variability, and (c) can be performed repeatedly at the same locations at different times during the curing process. This paper appears in transportation research record no. 1284, Cement, admixtures, and concrete 1990.
Samenvatting