Proposal for Method for Evaluating Concrete Strength at a Place in a Structure by means of Information Tests, at this and/or other Points

Abstract

The destructive character of the extraction of test specimens, which at present is the only test that provides trustworthy data with regard to strength, makes it necessary to assign a strength to areas in the structure that are at a greater or lesser distance from the extraction points. The variables of the problem are the number of extractions and their emplacement. At one end we would have the case in which samples are taken from all the structural parts at the risk of weakening the structure, above all during the sampling process itself, as well as the negative financial and time factors, that this procedure would imply. At the other far end we would place the case of evaluating the strength in a great structural area on the basis of the results from breaking a small quantity of test pieces, by way of an extrapolation without the required guarantees. Naturally, the number of test and their emplacement situates the problem in between the two above mentioned extremes. The necessary extrapolation of some results that by nature are not exhaustive, is then carried out with greater or lesser guarantee with regard to advance knowledge of the execution of the work: the greater this knowledge is, the easier it is to establish the strength relation between the specimens and the pieces, which without being represented directly by samples, can adapt themselves to their characteristics, either by proximity or known execution rhythm. The most important problem arises when there is not enough knowledge on how the work was carried out, so that it is impossible to relate the strength of the test specimens with the actual strength of the rest of the structure under investigation. In this case it does not seem possible to establish the relation between two points in the structure other than on the basis of the actual physical distances and the results obtained through the test specimens. This report dealts with the application of the Information theory to quantify these relations and to group the points at which the concrete strength is estimated.