Fuzzy method of conformity control for compressive strength of concrete on the basis of computational numerical analysis

Abstract

All concrete mechanical properties given in design codes of concrete and reinforced concrete structures are correlated with the characteristic compressive strength f ck. According to the EN 206-1 code, the characteristic strength is defined as the strength value below which 5 % of the population of all possible strength test results for given volume of concrete can be found. The value of f ck can be defined as 5 % quantile of the statistical distribution of the concrete compressive strength, tested on cylindrical samples with a diameter of 150 mm and a height of 300 mm or on cubic samples with dimensions 150 9 150 9 150 mm assuming the conversion factor of 0.8. In order to verify compliance of strength of the considered concrete with the designed characteristic strength (ascribed to concrete class), it should be checked if the test results meet the appropriate statistical criteria. The characteristic strength defined by specifying of concrete class is determined at the designing stage of the structure and it is the basic controlled parameter, providing the requirements are fulfilled by the producer. Despite numerous publications on disadvantages of the code compliance criteria, marginalization of the problem is still visible. Concepts and methods based on probabilistic or statistical approaches are often sourced of skeptical views on quality control because they are not very familiar to most engineers. In the paper the assessment of the code compliance criteria has been made using the numerical simulation on the basis of the programs which has been written in C??. The innovative method for estimation test coefficients values contained in the code compliance criteria has been proposed. This method was developed on the basis of fuzzy methods.

A Proposal of a Method for Ready-Mixed Concrete Quality Assessment Based on Statistical-Fuzzy Approach

“…Statistical quality control arrangements are a result of a “strategic game” between the producer and the consumer, whereas the standard conformity criteria represent a compromise between the quality, economy and safety requirements. Recommended measures for standard conformity control set out in EN-206 continue to evoke discussions, and the research conducted in the field reveals inadequacies [ 33 , 34 , 35 , 36 , 37 , 38 ]. These inadequacies concern the analyses of concrete batches conducted before quality assessment and refer to deficiency during continuous production.…”

“…Applying the conformity criteria set out in EN 206 [ 28 ] for a sample of size n = 3 (Method A) without providing the standard deviation value may contribute to the deterioration in concrete quality and, in consequence, lead to an excessive recipient risk [ 35 , 36 , 37 ].…”

Improving Energy Efficiency with the Risk of Investment of Reference to Urban Development of Zielona Góra

“…For the risk evaluation the multi-criteria analysis was applied in the study to assist the decisionmaking process in case of multiple criteria, and its main goal is to achieve one result on the basis of the possessed information [23,24]. In this method, a model is not formed in details, therefore it takes discrete values, a set of possible decisions is limited and countable.…”

A Case Study Analysis of Roundabouts Entry Capacity Localised on One of the Main Road in Sosnowiec City (Poland)

“…Roundabout described in [1] is an intersection with central island and one-way traffic road around the central island where vehicles are obliged to drive around it in a counter-clockwise direction. In road traffic engineering, roundabouts are the subject of multi-aspect researches both in terms of microscopic, macroscopic and mesoscopic analysis as well as many others topics, for example, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”