Durability is an important factor from an economical standpoint, as it enters vitally in the long-run cost of a pavement. It is also of importance on account of the infernal nuisance of having a roadway full of pot holes and rough places, to say nothing of the inconvenience to users of frequent repairs. Road officers are no more given to regarding the adage “a stitch in time saves nine,” than are other people, consequently non-durable roads are usually more or less out of order.
Durability depends upon the materials used in construction and their manipulation, proportioning, and other treatment; the character weight and density of traffic; system or lack of system in making repairs; the opening up of pavements for water, gas, and sewer or other purposes; building operations along the street; cleanliness; the absence or presence of street-car tracks; climate and possibly other factors.
Materials and Design.
—The physical properties of materials—their tensile, compressive, and shearing strengths, their elasticity, brittleness, etc.—while important elements in the durability of pavements, the design of the pavement, its thickness, the proportioning and mixing of parts, the laying, as well as the subgrade and its treatment are all elements that count very much also. No matter how good a material it can easily be spoiled in the handling. Some materials like vitrified brick and stone will last indefinitely on a little-used street while others like asphalt and creosoted wood block are much better for considerable wear. The use of definite and often meticulous specifications is to insure good materials and proper manipulation of the same, while the plans are carefully prepared ahead, so that durability and satisfaction may result.
© Underwood and Underwood
GIVING A MACADAM ROAD AN APPLICATION OF TARVIA BINDER
This is Followed by a Coat of Screenings and then the Road is Rolled Again.
© Underwood and Underwood