| Summary: | 碩士 === 國立成功大學 === 土木工程學系 === 87 === SUMMARY
This paper is concerning with an experiment about 103 aggregate samples taken from the main pebble and sand source fields located at land, river, shore, etc. in Taiwan. After doing the aggregate individual crushing and sizing, a alkali aggregate reactivity experiment has been done according to the chemical method ( ASTM C299-94) and the cement mortar bar method (ASTM C227-97a). The cement alkali content is adjusted to 1.38% by adding sodium hydroxide. And the cement mortar bar is made for further experiment by controlling the water amount flowing degree at 105∼110% in order to try to create a "Taiwan Island Use Judgment Chart of Alkali Aggregate Reaction". The test result is as follows:
1. Taiwan Island Use Judgment Chart of Alkali Aggregate Reaction :
The "(Sc Value －35) / Rc Value > 1 Considered Deleterious (including potentially deleterious)" is bad, and the "Sc Value －35 / Rc Value < 1 Considered innocuous ( including Grade A, B and C)" is good. The judgment curve is as Y=X－35. The innocuous section in the chart is classified as Grade A, B and C.
Grade A:Considered deleterious according to the ASTM C33 Appendix
Judgment Curve.
Grade B:Considered innocuous according to ASTM C33 Appendix
Judgment Chart Curve, but considered deleterious according to
ASTM C289 Judgment Chart.
Grade C:Considered innocuous according to ASTM C289 Judgment
Chart.
2. Result of Judgment according to ASTM C-289-95 Chemical Method Judgment Chart :
It reveals that the potential deleterious aggregates and the deleterious aggregates are concerned with the river channels as Black Stream (Ta Tu Hsi). Most of the samples from the rivers / streams located in the eastern part of Taiwan are deleterious, and most of materials from Tsung Ku (Hua Lien Stream, Hsiu Ku Luan Stream and Pi Nan Stream), Taitung are innocuous. Part of the river systems in the central area and the Kao Ping Stream area is deleterious.
3. Test Result of the Cement Mortar Bar :
Only the expansion rate (0.14%) of the Tung Ho (Taitung) Ma Wu Stream aggregate in 3 months surpasses 0.05%. All the others are within the limit. The conclusion of this experiment reveals that the Taiwan area alkali aggregate reaction is not so worse as the finding made with the chemical method.
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