A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Evaluation of Canadian Unconfined Aggregate Freeze-Thaw Tests for Identifying Nondurable Aggregates
Concrete is the most widely used material in construction. Aggregates contribute 60% to 75% of the total volume of concrete. The aggregates play a key role in concrete durability. The U.S. Midwest has many aggregates that can show distress in the field under freezing and thawing conditions. The objective of this research was to determine if the Test Method for the Resistance of Unconfined Coarse Aggregate to Freezing and Thawing, CSA A23.2-24A, could be used to differentiate good from poor performing aggregates in concrete. In this study, thirty-nine different Kansas aggregates were tested for freeze thaw resistance using a version of the CSA A23.2-24A test method modified to account for the crushed aggregate sizes used in KDOT concrete paving specifications. These results were compared to those of standard KDOT aggregate qualification tests. Twelve of these aggregates were also tested using the gradation specified in the CSA A23.2-24A standard. In addition to performing the CSA test method using a 3% sodium chloride solution, a subset of the aggregates were tested using either a 3% magnesium chloride or calcium chloride solution to determine the effects of the salt type on the aggregate performance. No correlation was found between the CSA A23.2- 24A test method results and the standard KDOT aggregate qualification tests. The results also indicated that the mass loss in the CSA A23.2-24A was similar for the aggregate sizes tested. The use of CaCl2 solution in the CSA A23.2-24A test resulted in lower mass loss than the use of the NaCl solution.
Evaluation of Canadian Unconfined Aggregate Freeze-Thaw Tests for Identifying Nondurable Aggregates
Concrete is the most widely used material in construction. Aggregates contribute 60% to 75% of the total volume of concrete. The aggregates play a key role in concrete durability. The U.S. Midwest has many aggregates that can show distress in the field under freezing and thawing conditions. The objective of this research was to determine if the Test Method for the Resistance of Unconfined Coarse Aggregate to Freezing and Thawing, CSA A23.2-24A, could be used to differentiate good from poor performing aggregates in concrete. In this study, thirty-nine different Kansas aggregates were tested for freeze thaw resistance using a version of the CSA A23.2-24A test method modified to account for the crushed aggregate sizes used in KDOT concrete paving specifications. These results were compared to those of standard KDOT aggregate qualification tests. Twelve of these aggregates were also tested using the gradation specified in the CSA A23.2-24A standard. In addition to performing the CSA test method using a 3% sodium chloride solution, a subset of the aggregates were tested using either a 3% magnesium chloride or calcium chloride solution to determine the effects of the salt type on the aggregate performance. No correlation was found between the CSA A23.2- 24A test method results and the standard KDOT aggregate qualification tests. The results also indicated that the mass loss in the CSA A23.2-24A was similar for the aggregate sizes tested. The use of CaCl2 solution in the CSA A23.2-24A test resulted in lower mass loss than the use of the NaCl solution.
Evaluation of Canadian Unconfined Aggregate Freeze-Thaw Tests for Identifying Nondurable Aggregates
S. K. Mummaneni (author) / K. A. Riding (author)
2012
82 pages
Report
No indication
English
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