Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Evaluation of the Use of Lithium Compounds in Controlling Alkali-Silica Reactivity in Concrete Pavement
Presented herein are findings from a three-year field trial in which lithium nitrate was applied on an existing concrete pavement in Norfolk, Nebraska, in the attempt to arrest on-going alkali-silica reaction (ASR) distress. Various destructive and non-destructive means were utilized to measure the effectiveness of the lithium treatments. Concrete cylinders were cored for petrography examination and split-tension testing. Powder samples were taken to determine lithium content. Nondestructive evaluations included using crack mapping, a Schmidt hammer, a velocity ('V') meter, and an impact echo apparatus. The results to date have not shown definitive benefits of the lithium material in arresting the ASR process; however, the observed lithium penetration by gravity soaking has been very limited. Presumably the pavement has not reached the deterioration state for optimal permeability for penetration of the lithium material. Other application techniques on hardened concrete such as surface pressurization and vacuum impregnation have been investigated to a limited extent as an alternate method to gravity soaking. The surface pressurization technique has shown promising results in so far as achieving higher lithium contents. Effort is now needed in achieving higher lithium contents on a larger scale so that a more realistic evaluation of the effects of the lithium can be performed.
Evaluation of the Use of Lithium Compounds in Controlling Alkali-Silica Reactivity in Concrete Pavement
Presented herein are findings from a three-year field trial in which lithium nitrate was applied on an existing concrete pavement in Norfolk, Nebraska, in the attempt to arrest on-going alkali-silica reaction (ASR) distress. Various destructive and non-destructive means were utilized to measure the effectiveness of the lithium treatments. Concrete cylinders were cored for petrography examination and split-tension testing. Powder samples were taken to determine lithium content. Nondestructive evaluations included using crack mapping, a Schmidt hammer, a velocity ('V') meter, and an impact echo apparatus. The results to date have not shown definitive benefits of the lithium material in arresting the ASR process; however, the observed lithium penetration by gravity soaking has been very limited. Presumably the pavement has not reached the deterioration state for optimal permeability for penetration of the lithium material. Other application techniques on hardened concrete such as surface pressurization and vacuum impregnation have been investigated to a limited extent as an alternate method to gravity soaking. The surface pressurization technique has shown promising results in so far as achieving higher lithium contents. Effort is now needed in achieving higher lithium contents on a larger scale so that a more realistic evaluation of the effects of the lithium can be performed.
Evaluation of the Use of Lithium Compounds in Controlling Alkali-Silica Reactivity in Concrete Pavement
C. Y. Tuan (Autor:in) / M. T. Kelly (Autor:in) / M. E. Buss (Autor:in)
2005
110 pages
Report
Keine Angabe
Englisch
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