Evaluation of Maintaining Adequate Air Void System for PCC

Kentucky has historically utilized the pressure method for determination of the air content of concrete mixtures. This procedure does not provide any information relating to the size of the air entrained or the spacing of the air bubbles. Both factors can affect the durability of in-situ concrete. Questions have arisen relating to the compatibility of the varying quality of fly ash which is used in Kentucky, with the different products which are used as air entraining agents and admixtures. The effects these variables have on the spacing and size of the entrained air and resulting performance is unknown at this time. This research will identify if these problems exist and if so what steps should be taken to minimize their effect on the resulting concrete. Various techniques are available to determine the size and spacing of the entrained air within both plastic and hardened concrete. Each ofthese techniques has both advantages and disadvantages, which will be identified in this research proj ecl.