1. Roman Roads : Romans started Road construction in 312 BC and constructed Appian way of length over 580 km.
Main Features:
(a) They were straight regardless of Gradients.
(b) Total thickness was as high as 0.75 to 1.2 meters.
(c) The wearing course consists of dressed large stone blocks set in lime mortar.
(d) Roads are built after soft soil was removed and a hard stratum was reached.
Method of Road Construction
First the two parallel trenches were built on either side of the planned road, with the resulting earthworks, stone, etc., being dumped and built up in the space between the two ditches. The Agger, as this was called, could be up to 6 ft. (1.8 m) high and 50 ft. (15 m) wide. Alternatively it could be very slight or almost non-existent as was the case with most minor roads.
Next, the diggers would make a shallow 8 to 10 foot wide depression down the length of the agger, and line the edges with kerb stones to hold the entire construction in place. The bottom of this depression would then be lined with a series of stone fillers. 6 to 8 inch stones would form the foundation layer, with fist sized stones placed on top. In early roads the remaining gap would then be filled in with course sand to fill between the stones and to cover them by approximately 1 ft.
2. Tresaguet Construction : "Pierre tresaguet" developed roads in France during 1764 A.D.
Main Features :
(a) Thickness was of order of 30cm.
(b) Consideration was given to subgrade moisture and drainage of surface water.
(c) The top wearing surface was made up of smaller slope having a cross slope of 1 in 45 to the surface to provide surface drainage.
(d) Shoulder sloping was also provided of the order of 1 in 20.
Method of Road Construction
First of all an earth foundation was excavated parallel with but about ten inches below the finished surface of the new road. This was convex in cross section to encourage water to drain off the finished surface.
Next, large stones were laid on edge and any protruding pieces on their upper edges broken off to leave an even surface. This stone foundation was covered with a second course of smaller rounded stones.
Finally a third layer of hard broken stone, (about the size of walnuts) was spread by a shovel to produce the surface layer.
3. Metcalf Construction : "John Metcalf" was working in England and he followed the instruction of Robert Philip. John Metcalf (1717–1810), also known as Blind Jack of Knaresborough or Blind Jack Metcalf. In the period 1765 to 1792 he built about 180 miles (290 km) of turnpike road, mainly in the north of England.
Main Features :
( a) Roads should have good foundation.
(b) smooth convex surface to allow rainwater to drain quickly into ditches at the side.
4. Telford Construction : His work started in early 19th century in England. He was one of the first engineers to test his materials thoroughly before construction.
Main Features :
(a) Telford provided level subgrade of width 9 meters.
(b) A binding layer of wearing course 4 cm thick was provided with cross slope of 1 in 45.
(c) Thickness of foundation stone varied from 17 cm at edges to 22 cm at the centre.
5. Macadam Construction : Macadam is a type of road construction pioneered by Scottish engineer John Loudon McAdam around 1820. He put forward an entirely new method of road construction as compared to all the previous methods. The first attempt to improve the road condition was made by him in 1815. This was the 1st method based on scientific thinking. The first macadam road built in the United States was constructed between Hagerstown and Boonsboro, Maryland and was named Boonsboro Turnpike Road.
Main Features :
(a) Macadam was the first person who suggested that heavy foundation stones are not at all required to be placed at the bottom layer. He provided stones of size less than 5 mm to a uniform thickness of 10 cm.
(b) The size of broken stone for the top layers was decided on the basis of stability under animal drawn vehicles.
(c) The importance of subgrade drainage and compaction was given so the subgrade was compacted and prepared with cross slope of 1 in 36.
(d) The pavement surface was also given the cross slope of 1 in 36.
(e) Total thickness was kept uniform from edge to centre to a minimum value of 25 cm.
Method of Road construction
Subgrade is compacted and prepared with a cross slope of 1 in 36 up to a desired width about 9 meters. Broken stones of strong variety, all passing through 5 cm size sieve were compacted to thickness of 10 cm. The second layer of strong broken stones of size 3.75 cm was compacted to thickness of 10 cm. The top layer consists of stones of size less than 2 cm compacted to a thickness of about 5 cm and finished so that the cross slope of pavement surface was also in 1 in 36.
6. Water Bound Macadam : Most of the driveways built today are those which are known as Telford roads . These are usually constructed of twelve inches of stone over all. An eight-inch foundation is provided of hard quarry stone, laid on edge, with the longest dimension placed at a right angle to the side line of the drive. Very often this large stone can be found on the property . After the stones are placed they should be gone over with napping hammers and made fairly even by breaking off the irregular edges; the pieces of stone so broken off should be used to fill in chinks.
Over this should be placed three inches of one and one-half inch stone. Then a light covering of three-quarter inch stone may be placed as a binder and finished with clean breaker dust. The drive should be rolled before and after placing the three-quarter inch stone, with a roller weighing not less than five tons. The three-quarter inch stone and the dust should never be mixed together; the dust will work through and the stone find the surface, making it rough and troublesome. When rolling the finished surface it should be wetted constantly until a wave of water appears in front of the roller.
Main Features:
(a) They were straight regardless of Gradients.
(b) Total thickness was as high as 0.75 to 1.2 meters.
(c) The wearing course consists of dressed large stone blocks set in lime mortar.
(d) Roads are built after soft soil was removed and a hard stratum was reached.
Method of Road Construction
First the two parallel trenches were built on either side of the planned road, with the resulting earthworks, stone, etc., being dumped and built up in the space between the two ditches. The Agger, as this was called, could be up to 6 ft. (1.8 m) high and 50 ft. (15 m) wide. Alternatively it could be very slight or almost non-existent as was the case with most minor roads.
Next, the diggers would make a shallow 8 to 10 foot wide depression down the length of the agger, and line the edges with kerb stones to hold the entire construction in place. The bottom of this depression would then be lined with a series of stone fillers. 6 to 8 inch stones would form the foundation layer, with fist sized stones placed on top. In early roads the remaining gap would then be filled in with course sand to fill between the stones and to cover them by approximately 1 ft.
2. Tresaguet Construction : "Pierre tresaguet" developed roads in France during 1764 A.D.
Main Features :
(a) Thickness was of order of 30cm.
(b) Consideration was given to subgrade moisture and drainage of surface water.
(c) The top wearing surface was made up of smaller slope having a cross slope of 1 in 45 to the surface to provide surface drainage.
(d) Shoulder sloping was also provided of the order of 1 in 20.
Method of Road Construction
First of all an earth foundation was excavated parallel with but about ten inches below the finished surface of the new road. This was convex in cross section to encourage water to drain off the finished surface.
Next, large stones were laid on edge and any protruding pieces on their upper edges broken off to leave an even surface. This stone foundation was covered with a second course of smaller rounded stones.
Finally a third layer of hard broken stone, (about the size of walnuts) was spread by a shovel to produce the surface layer.
3. Metcalf Construction : "John Metcalf" was working in England and he followed the instruction of Robert Philip. John Metcalf (1717–1810), also known as Blind Jack of Knaresborough or Blind Jack Metcalf. In the period 1765 to 1792 he built about 180 miles (290 km) of turnpike road, mainly in the north of England.
Main Features :
( a) Roads should have good foundation.
(b) smooth convex surface to allow rainwater to drain quickly into ditches at the side.
4. Telford Construction : His work started in early 19th century in England. He was one of the first engineers to test his materials thoroughly before construction.
Main Features :
(a) Telford provided level subgrade of width 9 meters.
(b) A binding layer of wearing course 4 cm thick was provided with cross slope of 1 in 45.
(c) Thickness of foundation stone varied from 17 cm at edges to 22 cm at the centre.
5. Macadam Construction : Macadam is a type of road construction pioneered by Scottish engineer John Loudon McAdam around 1820. He put forward an entirely new method of road construction as compared to all the previous methods. The first attempt to improve the road condition was made by him in 1815. This was the 1st method based on scientific thinking. The first macadam road built in the United States was constructed between Hagerstown and Boonsboro, Maryland and was named Boonsboro Turnpike Road.
Main Features :
(a) Macadam was the first person who suggested that heavy foundation stones are not at all required to be placed at the bottom layer. He provided stones of size less than 5 mm to a uniform thickness of 10 cm.
(b) The size of broken stone for the top layers was decided on the basis of stability under animal drawn vehicles.
(c) The importance of subgrade drainage and compaction was given so the subgrade was compacted and prepared with cross slope of 1 in 36.
(d) The pavement surface was also given the cross slope of 1 in 36.
(e) Total thickness was kept uniform from edge to centre to a minimum value of 25 cm.
Method of Road construction
Subgrade is compacted and prepared with a cross slope of 1 in 36 up to a desired width about 9 meters. Broken stones of strong variety, all passing through 5 cm size sieve were compacted to thickness of 10 cm. The second layer of strong broken stones of size 3.75 cm was compacted to thickness of 10 cm. The top layer consists of stones of size less than 2 cm compacted to a thickness of about 5 cm and finished so that the cross slope of pavement surface was also in 1 in 36.
6. Water Bound Macadam : Most of the driveways built today are those which are known as Telford roads . These are usually constructed of twelve inches of stone over all. An eight-inch foundation is provided of hard quarry stone, laid on edge, with the longest dimension placed at a right angle to the side line of the drive. Very often this large stone can be found on the property . After the stones are placed they should be gone over with napping hammers and made fairly even by breaking off the irregular edges; the pieces of stone so broken off should be used to fill in chinks.
Over this should be placed three inches of one and one-half inch stone. Then a light covering of three-quarter inch stone may be placed as a binder and finished with clean breaker dust. The drive should be rolled before and after placing the three-quarter inch stone, with a roller weighing not less than five tons. The three-quarter inch stone and the dust should never be mixed together; the dust will work through and the stone find the surface, making it rough and troublesome. When rolling the finished surface it should be wetted constantly until a wave of water appears in front of the roller.
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