214. 4-21: Obtaining Cores and Interpreting Core Compressive Strength . . . Chapter 5 summarizes coring tech-niques that should result in high-quality, undamaged, repre-sentative test specimens Chapter 6 describes procedures for testing cores and detecting outliers by inspection of load-machine displacement curves or using statistical tests from ASTM E178
Guide for Obtaining Cores and Interpreting Compressive Strength Results These criteria specify the circumstances when core tests are permitted, the number of cores to be tested, the conditioning of the cores before testing, the limits on the time interval between coring and testing, and the basis for determining whether the concrete in the area represented by the core strengths is structurally adequate
Low Strength Results and Core Testing Q. - Concrete Q A Low Strength Results and Core Testing Q Lower-than-specified compressive strength was determined from results of cylinder testing of one concrete placement on our project How can we determine if we need to take cores for additional testing and, if we do, what’s the correct procedure to follow?
Low-strength cylinder test results Low-strength cylinder test results Q If a structure is being built in accordance with the requirements of ACI 318-19, what must be done when a low-strength test occurs? A Section 26 12 6 1 of ACI 318-19 states that if any strength test of standard-cured cylinders falls below the specified compressive strength by more than the limit allowed for acceptance, or if tests of field-cured cylinders
Getting to the Core of Core Testing SIZE OF CORES – THE SMALLER THE CORES, THE GREATER THE POTENTIAL FOR VARIABILITY AND LOWER STRENGTH FOUR INCH DIAMETER CORES, OR LARGER, SHOULD BE USED WHENEVER POSSIBLE DAMAGE TO CORES DURING DRILLING – PORT AUTHORITY TEST SHOWS THIS IS NOT AN ISSUE IF CORING EQUIPMENT IS IN GOOD CONDITION AND PROPER PROCEDURES ARE FOLLOWED
Pieces of rubber stopper floating in oil (23g needle tore them off) Stuff we inject eventually ends up inside our brain and effects the very core of our existence After one inserts a needle through the stopper of a medication vial, a small piece of the stopper is sometimes sheared off (known as coring) and can be noticed floating on the liquid medication