Title : EMERGING RAPID AGGREGATE AND CONCRETE TEST METHODS FOR DEVELOPING PERFORMANCE BASED ASRRESISTANT CONCRETE MIXES
Authors : Anal K. Mukhopadhyay, Ph.D., P.G. , Kai-Wei Liu, Ph.D., E.I.T.
Publication : 8 - 10, October 2015
Volume : 2
Pages :
Price : 250
Abstract : There is a growing demand for a rapid and reliable alkali silica reaction (ASR) test method and formulate ASR resistant concrete mix. An effective way of tailoring mix design depending on the level of protection needed and by proper utilization of locally available materials is warranted. The main objective of this study was to develop rapid aggregate and concrete test methods and a combined innovative approach for formulating performance based ASR resistant mixes. An innovative step by step approach has been developed to formulate ASR resistant mix based on four recommended steps. In Step 1, determination of aggregate ASR compound activation energy (CAE) and threshold alkalinity (THA) by using a rapid aggregate chemical test called volumetric change measuring device (VCMD) is performed. Mix design development by applying mix design controls ± special protection measures based on CAE, THA and some considerations on ambient conditions is a part of Step 2. In Step 3, verification and adjustment of the mix developed in Step 2 is performed based on THA and pore solution alkalinity (PSA) relationship - PSA needs to be below THA in order to prevent/minimize ASR. Mix design validation by using a new rapid concrete cylinder test (RCCT) is a part of Step 4. Different options (options I, II, III and IV) involving different combinations of the proposed four steps have been developed in order to formulate ASR resistant mixes with different degree of reliability. The proposed approach has the ability to rapidly assess the ASR potential of each aggregate at various alkali loadings and tailoring mix design depending on the level of protection needed.