EVALUATION OF THE QUALITY OF FRESH CONCRETE BY ULTRASONIC MEANS

DEVELOPMENT OF INNOVATIVE NONDESTRUCTIVE TECHNOLOGIES IS PROPOSED FOR THE QUALITY ASSURANCE AND QUALITY CONTROL OF FRESH (NEW) CONCRETE. THE PROJECT IS DIVIDED INTO TWO TASKSNAMELY, ACTIVITIES RELATED TO THE DEVELOPMENT OF IMPROVED NONDESTRUCTIVE TESTS FOR THE FOLLOWING CONCRETE PROPERTIES: 1. FOR FRESH CONCRETE BEFORE PLACEMENT: STRENGTH POTENTIAL; UNIFORMITY; COMPOSITION, INCLUDING WATER-CEMENT RATIO; AIR VOID SIZE DISTRIBUTION; 2. FOR FRESH CONCRETE AFTER PLACEMENT IN PLACE: AIR CONTENT AND AIR VOID SIZE DISTRIBUTION; DENSITY; COMPOSITION; STRENGTH DEVELOPMENT. LABORATORY EXPERIMENTS ARE DESCRIBED. THE RESULTS WILL BE SUBMITTED TO THOROUGH COMPUTER ANALYSIS AND STATISTICAL TREATMENT. ON THE BASIS OF THIS, THE MOST PROMISING LABORATORY METHODS WILL BE SELECTED AND RECOMMENDED FOR FURTHER RESEARCH, INCLUDING FIELD TRIALS, IN PHASE II. THE MOST IMPORTANT PORTION OF THE PROJECT IS THE DEVELOPMENTOF INNOVATIVE TECHNOLOGIES. A MAJOR INNOVATION PROPOSED IS THE USE OF ULTRASONIC WAVES OF HIGH FREQUENCY. THEIR USE INFRESH CONCRETE IS MADE POSSIBLE BY NEW PROCEDURES IN SIGNAL-TO-NOISE RATIO ENHANCEMENT AND CLUTTER SUPPRESSION DEVELOPED AT DREXEL UNIVERSITY. THUS, CHANCES ARE GOOD THATTHE APPLICATION OF HIGH-FREQUENCY ULTRASONIC WAVES WILL BE AS FRUITFUL IN CONCRETE TESTING AS HAS BEEN WITH METALS, POLYMERS AND OTHER MATERIALS.