A Novel Approach for the Assessment of ASR Susceptibility of Concrete Mixtures in Airfield Pavements and Infrastructure

During the last 20 yr, the Federal Aviation Administration made significant efforts to develop one of the most comprehensive specifications to prevent alkali-silica reaction (ASR) in new construction [see the Advisory Circular (AC) 150/5370-10H, Item P-501]. The AC was effective, to a large extent, in preventing ASR in new airport pavements during the last 10 yr. However, the inherent limitations of the ASR accelerated tests [(former) American Society for Testing and Materials (ASTM) C1260 and C1567 standards] recommended in the AC often resulted in the unnecessary rejection of aggregates with historically nonreactive performance in the field, and the overdependence on supplementary cementitious materials. The Federal Highway Administration recently introduced a new reactivity index (RI) to predict ASR that can help resolve these problems. The novel RI can be used to develop two different types of screening tests to evaluate aggregates alone and/or the job mix designs. Both protocols lack several limitations affecting traditional accelerated ASR tests. The objective of the study was to explore the applicability of the new RI for ASR screening in aggregates used in the construction of airport facilities. ASR of the selected aggregates for the study varied from nonreactive to slow reactive based on their historic field records. The ASR susceptibility of the aggregates was determined using two different testing protocols based on the RI. The first protocol, known as the Turner-Fairbank ASR susceptibility test, was used to determine ASR of the aggregates alone. The second protocol evaluated the ASR susceptibility of the job mix designs. The results of the two new ASR screening protocols were compared against the screening protocols obtained using AC 150/5370-10H, Item P-501, and ultimately with the historical field performance of the aggregates. The new RI was capable of accurately identifying a slow reactive aggregate that triggered ASR deterioration in the concrete pavement and in other structures at Denver International Airport after 25 yr of service life.