Title: Modifications to ASTM C1293 that Allow Testing of Low‑Alkali Binder Systems

Author(s): Soley Unnur Einarsdottir and R. Douglas Hooton

Publication: Materials Journal

Volume: 115

Issue: 5

Appears on pages(s): 739-747

Keywords: alkali leaching; alkali-silica reaction; durability; lowalkali cement; storage conditions; supplementary cementitious materials; test method

DOI: 10.14359/51702350

Date: 9/1/2018

Abstract:
When carrying out laboratory tests for alkali-silica reaction (ASR) mitigation, the currently used ASTM C1293 method cannot be used for evaluating the benefits of using low-alkali cement. The effects of cement alkali content and supplementary cementitious material (SCM) replacement on the expansion and leaching in the concrete prism test were investigated, as well as ways to minimize alkali leaching. Approximately 45% of the alkalis leach from 100% portland cement (PC) concrete prisms during the 2-year test period. SCM replacement decreased the alkali leaching to approximately 25%, likely due to a more impermeable pore structure. The most effective way to minimize the leaching was to cover the upper two-thirds of each prism with a plastic bag, reducing the alkali leaching to only 10%. By modifying the alkali boosting procedure in the concrete prism test (CPT) and improve the storage conditions to minimize alkali leaching, it is possible to use this test to evaluate the benefits of concrete mixtures made with low-alkali cements and combinations with SCMs.