El concepto de "Paste efficiency"

The "Paste efficiency" concept. It's application to estimate in situ the strength of hardened concrete

One of the more controversial application and, in spite of that, more used of the ultrasonic pulse method is the estimation of in situ concrete strength, if we atke into account the number of variables which can influence the results obtained in the test. The international normative and reccomendations, hence the spanish norme UNE, show that is neccesary to obtain specific calibrations between ultrasonic pulse velocity and concrete strength for every concrete under examination. The "Paste efficiency" concept, from H. N. Tomsett, based in the pulse velocity difference between a control specimen and the concrete in the structure, can be used to estimate the air-dried samples strength and hence in situ concrete strength. This paper presents an experimental research that has been developed under concrete which is normally placed in prestressed beams made in a central factory. The aims of this research has been to verify the application of the "Paste efficiency" concept, and levels of accuracy that we can achieve in estimating in situ hardened concrete strength placed in real prestressed beams, by means of "Paste efficiency" concept.