Download PDFOpen PDF in browserDetection of Alkali-Silica Reactivity using Field Exposure Site Investigation8 pages•Published: May 15, 2022AbstractThe main objective of this research is to study the impact of supplementary cementitious materials (SCMs) on mitigating Alkali-Silica Reactivity (ASR) of hardened concrete. ASR is a deleterious reaction between alkali content within the cement and highly reactive silica content available in some aggregate sources across the United States. ASR results in the formation of an expansive white-like gel that adds internal tensile stresses within hardened concrete. Increased tensile stress results in the formation of cracks, dissipation of additional moisture, and reinforcement corrosion. In this research project, large scale concrete blocks, with aggregates from different sources, were poured using different percentages of SCMs. An exposure site was developed for the poured blocks to investigate ASR possible impact on concrete. ASR impact was measured by calculating concrete blocks expansion over a time span of two years. The outcomes of the research showed that different aggregates result in different rates of expansion. The use of SCMs resulted in mitigating ASR and limit concrete expansion. The replacement of 25% to 30% of cement weight with SCMs (fly ash) is sufficient to halt ASR, and improve the long- time performance of concrete structures.Keyphrases: alkali silica reactivity, concrete blocks, cracking, expansion, supplementary cementitious materials In: Tom Leathem, Wes Collins and Anthony Perrenoud (editors). ASC2022. 58th Annual Associated Schools of Construction International Conference, vol 3, pages 74-81.
|
