Thursday, August 23, 2012

Highway Engineering Basics

If there is something that has facilitated the time-saving transportation it is the construction of roads. It is believed that road construction engineering existed in the 2500 - 3500 BC where ancient civilizations called the Mohenjadaro and Harappan civilizations built rather sturdy roads for transportation. Certain ancient books from similar times talked of the rules for regulating traffic, punishments for traffic offences and the construction dynamics of roads for transportation.

Some of the best of road construction engineering evolved at the onset of the 20th century where the Romans were known to have constructed roads made out of stone lined with layers of lime mortar, broken stones in lime concrete, lime concrete and large stone slabs placed one above the other in the same order. French roads also built in those times depicted a similar engineering but lesser number of stone layers to make roads. The common thing about these roads was that they provided good drainage and good materials were used in its construction lasting it as long as till the current times today.

The aggregates used for road making involved in highway engineering of the modern times takes into consideration the consistency of the materials quantity and quality used, its specific gravity, absorption and polishing capabilities and finally its grading and particle shape. When it comes to highway engineering the best of the aggregates are used to give a durable and tear-resistant end product. Bituminous road surfacing where the uses of construction materials like Asphalt and concrete require the careful specifications with design also require attention to the kind of bituminous binder used. For this reason, the binder undergoes a series of tests for its properties before they are included in the highway construction.

Highway engineering basics concerns various tests that

- determine the flakiness and elongation of the aggregate particles, one that determines the aggregate crushing value (ACV),

- one that determines the aggregate impact value (AIV),

- one that determines the hardness and abrasiveness of the aggregates,

- one that determines viscosity of the bituminous binder,

- one that determines the volatility of the binder through a flash and fire point test,

- one that determines the internal cohesion of the bitumen through a ductility test,

- one that determines and characterizes the rate of setting of the bitumen using the softening point also known as the Ring and Ball test,

- one that determines the stability and resistance to plastic flow of the bitumen,

- one that determines the resistance to plastic flow of compressed bituminous mixture via a test called the Hubbard field test,

- one that determines the stability flow test of compacted aggregates through a design trial mix of plastic concrete.

The author is a prominent writer of the topics that concern highway engineering basics. The highway engineering is a complex process and with evolving technologies the construction times are considerably reduced with maximum output.

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