US 12,247,970 B2
Method for the assessment of alkali-silica reactivity of aggregates and concrete mixtures
Terence S Arnold, Washington Grove, MD (US); Chandni Balachandran, McLean, VA (US); and Jose F Munoz, Ellicott City, MD (US)
Assigned to The U.S. Department of Transportation. Federal Highway Administration, Washington, DC (US)
Filed by Terence S Arnold, Washington Grove, MD (US); Chandni Balachandran, McLean, VA (US); and Jose F Munoz, Ellicott City, MD (US)
Filed on Dec. 4, 2020, as Appl. No. 17/112,090.
Prior Publication US 2022/0317109 A1, Oct. 6, 2022
Int. Cl. G01N 33/38 (2006.01); C04B 40/00 (2006.01)
CPC G01N 33/383 (2013.01) [C04B 40/0032 (2013.01); C04B 40/0082 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A chemical test method for assessing the likelihood of the formation of alkali-silica reaction gels in concrete comprising the steps of:
preparing a plurality of replicates for simulating a plurality of long-term pore conditions using a preselected aggregate;
heating a first portion of said plurality of replicates in a first oven for a period of time;
heating a second portion of said plurality of replicates in a second oven for said period of time;
filtering contents of each of said plurality of replicates after the expiry of said period of time;
measuring concentrations of silicon, aluminum, and calcium in each of said contents from said plurality of replicates; and
calculating a reactivity index value for said preselected aggregate in each of said plurality of replicates using said measured concentrations of silicon, aluminum, and calcium from each of said contents of each said plurality of replicates by dividing said measured concentration of silicon by a combined concentration of both said measured concentrations of aluminum and calcium, wherein said reactivity index value is indicative of an alkali-silica reactivity of said preselected aggregate in each of said plurality of simulated long-term pore conditions.