The Use of Seismic Tests to Assess the Properties of Portland Cement Concrete During Curing

«In situ» measurements of surface wavevelocityon two prototype concrete slabs indicate that seismic measurements offer a reliable alternative to con-ventional penetration resistance and cylinder com-pression tests for determining the stiffness of Port-land cement concrete during curing. The surfacewave velocity was determined using a nondestruc-tiveand nonintrusive technique called the SpectralAnalysis of Surface Waves (SASW) method.Both the surface wave velocity and penetration re-sistance exhibit similar rates of increase during theinitial stages of curing, suggesting that «in situ»measurements of surface wave velocity are poten-tially useful for assessing the degree of curingwhich has occurred. At later stages of curing,values of Young's moduli calculated from «in si-tu» seismic tests agree wellwith values of Young'smodulus from cylinder compression tests.