John Knapton's pictorial guide to paving through the ages.

You might also wish to view a Total Quality paving design method, recycling pavers in Rotterdam, permeable paving in Brazil and road design guidance notes.

 

One of John Knapton's interests is paving systems and this page explains how recent developments in paving are in effect an evolution of Roman road construction. If you are interested in the history of paving, JK can supply you with his "Roman Roadbuilding" article, which he has presented in many parts of the world.

 

The picture below shows the first Newcastle-Carlisle A69 road contract in progress in 170AD. Note how the Romans understood the need for drainage and a closely fitting surface. The quality control comprised the Roman soldier inserting his knife into the joint between pavers. If the blade entered the joint freely, the gap was too wide and the blade was subsequently inserted into the Ancient Briton responsible.

 

 

Because the articulating front axle remained undiscovered until the 13th century, turning corners with Roman carts was no easy task. (one of the reasons for straight Roman roads). Consequently, at corners, ruts were carved into the road surfacing materials to encourage the carts around corners. The next picture shows a rut road in Pompei. Note also the stepping stones to keep pedestrians out of the mire.

 

 

The Romans landed in Britain in 42BC, after several previous unsuccessful attempts. They landed on the north Kent coast, travelled west until the River Thames was fordable and then conquered Colchester & St. Albans heading north and north west. The Roman road network is amazingly similar to the present day UK trunk road network. The next picture shows the major Roman roads. It is interesting to note that the Romans feared the British and always preferred the perils of the North Sea to those of travelling the UK road network (little has changed in this respect). They established Newcastle as their port in the North East of England where they came ashore to service Hadrian's Wall. Contrary to popular belief, Hadrian's wall does not mark the edge of the Roman Empire, the Romans continued north as far as Perth, and then felt that enough was enough

 

 

Not much happened in the world between 150AD and 1994 when JK introduced a few innovations into paving on the project shown below in Hartlepool. Throughout the 1980's there had been a number of paving projects performing poorly in town centres. To resolve this, JK introduced the use of steel fibre reinforced concrete roadbases installed by laser guided screeding machines as shown in the next picture. He also developed enhanced specifications for paver bedding sands whereby the sand finer than 75 microns was largely eliminated from the bedding material. The result of these changes is a perfectly satisfactory method of designing and constructing roads which are proving cost effective and durable. Collaborating with academics at Queensland University of Technology (QUT), he has recently established the reasons for the enhanced performance of no fines bedding sands (well done Frank, Trevor, Les, Melanie & Pat at QUT). The picture below shows the laser guided screeding machine in operation at Victoria Road, Hartlepool.

 

 

The outcome of this project can be appreciated in the next two pictures. The road is trafficked by double decker buses and other heavy vehicles and is exactly where it was built, no deformation whatsoever.

 

 

The detailing of any project is crucial to long term performance. See the edge detail in the next picture. Placing pavers end to end along the edge tidies up the cutting operation - cutting between two similar materials hides defects. Also, look how the placing of small square pavers away from the edge has precluded the use of small, and therefore vulnerable, pieces right at the edge. The yellow and white tape on the road surface proved less successful and paint is now commonly preferred.

 

 

One of the few things that did happen between 150AD and 1994 was Pine Street, Seattle in 1990. The original street failed in a few hours as a result of the bedding sand containing 10% fine material when it should have contained less than 1%. JK was engaged by Seattle Engineering Department to advise on the remedial work. By changing the sand, a durable road has been constructed. The surface comprises three colours of granite pavers from California, Minnesota and Texas. The road surface was constructed to a traditional Indian basket weave pattern. Because the Indians always included a deliberate fault in their weaving to keep out evil spirits, the designers of Pine Street did so likewise - see the picture below. It didn't work.

 

 

Here's an important tip - never, never install pavers over a mortar bed if traffic will travel over them. Here is just one of thousands of projects where the mortar bed has failed. This one was in Bellevue, Washington State, USA.

 

And finally, the diagram below shows why walking on pavers can damage them. The curve illustrates the vertical force transmitted to a pavement during a footstep. The right hand axis translated forces to stresses which are applied through a stiletto heal. I'll leave you to determine how much more damaging a stiletto is than an 18 wheel truck - clue - its more than 10 times worse.

 

 

"Sir, hell is paved with good intentions"

Samuel Johnson

 

"They Paved Paradise, put up a parking lot"

Jodi Mitchell

 

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