We were discussing about alkali silica reaction (ASR) suppressor; there we learn about finely divided siliceous material and application of pozzolana with other suppressor in glass aggregate concrete. The glass aggregate that produce ASR also produce ASR suppression when ground in fine size enough to behave like pozzolana.
When glass sand (as fine aggregate) has size within (1.18 - 2.36) mm, exhibits severe alkali-silica reaction results maximum ASR expansion consequently. Here we like to include that the reaction is occurred when alkali-silica of reactive from come into contact. Now if we reduce silica content in concrete mix ASR can be controlled, at the same time if we control alkali sources ASR can also be reduced.
Glass aggregate that derived from silica-soda-lime sources produce ASR reaction from both sources i.e.
- A potential source of alkali source
Glass as a very finely divided from can also be used as cement replacement, but suitable when substitution fraction is low. There have also interesting behavior of glass that performance of glass also depends on its color, say flint and green color glass show better performance than amber glass.
Most of glass waste collected from United States are of soda-lime type; as discussed above these glasses are more susceptible to ASR reaction. In case of such application fly ash is applied to replace cement together with replacement of natural sand with crushed glass. Sometimes full replacement of sand is also tried.
Dear reader we will provide a quantitative calculation about partial and full replacement of sand with crush glass in our next post.