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Page:Popular Science Monthly Volume 61.djvu/226

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POPULAR SCIENCE MONTHLY.

to the surface, but also, when properly set and dried before the surface is laid, keeps the surface as free as is possible under the circumstances from ground water, and thus contributes to the longevity of the surface.

PSM V61 D226 Cass ave detroit mich pavement laid 1889.png

Cass Avenue, Detroit Mich. Pavement Laid 1889. Showing Street-Cleaning under the 'Orderly System.'

The concrete surface, having been laid as nearly as possible of the proper contour, and having been thoroughly set, dried out and swept clean, is covered with a binder course to fill the inequalities of the concrete and form a bond between the concrete and surface that will