Common Contaminants in Glass Powder as Concrete Constituents

We have already learnt about glass powder that can be used in concrete as fine aggregate, coarse aggregate or as replacement of binding agent like cement. The glass powder has some contaminants. Our aim is to learn about contaminants in glass powder.

The screening method for contaminants will be discussed in our upcoming post. Here we will just discuss about contaminants including moisture content, lime content and loss under ignition. Though glass powder and process glass are derived from identical sources, there have some difference between them. Both materials have soluble silica content which is obviously an identical behavior but the difference lies in particle size.

It is established, through different analysis that crushed glasses have contaminants of following forms:

a. Small amount of polymers

b. Small acrylic content found in glass that used as architectural purposes.

c. Polyvinyl butylenes from ELV (End of Life Vehicle) glass. The contaminants can be expressed as PVB.

Notice that first and second types of contaminants are found in small amount, but third one, polyvinyl butylenes covers more than 90 percent of contaminants.

There may have some organic contents in crushed glass which may be paper residue comes from labels provided in bottle and other glass sources. Regarding moisture, there has insignificant amount of moisture (about 0.29%). Free lime contents are 0.26% and 1.22% for glass powder and crushed glass respectively. An about 0.02% loss is found under ignition analysis.

Notice that first and second types of contaminants are found in small amount, but third one, polyvinyl butylenes covers more than 90 percent of contaminants.