{"id":575,"date":"2014-01-06T18:59:12","date_gmt":"2014-01-06T18:59:12","guid":{"rendered":"http:\/\/mocktheorytest.com\/resources\/?p=575"},"modified":"2019-02-05T11:21:10","modified_gmt":"2019-02-05T11:21:10","slug":"why-do-we-need-road-works","status":"publish","type":"post","link":"https:\/\/mocktheorytest.com\/resources\/why-do-we-need-road-works\/","title":{"rendered":"Why do we need road works?"},"content":{"rendered":"

What causes tarmac to crack?<\/h2>\n

Roads degrade in a number of different ways and therefore roadworks are a necessary part of maintaining our roads.<\/p>\n

\"transverse-tarmac-cracking\"Edge cracks<\/h3>\n

These are lateral lines along the edge of the road, like the tarmac is falling away. It can be caused by a lack of drainage, vegetation growing into the edge of the tarmac, settlement of the underlying material, a weak base or subgrade layer, heavy traffic along the edge (such as agricultural traffic that might keep hard left as not to hold up the general flow of traffic), and frost heave (where water in the ground expands and contracts, lifting and dropping the asphalt).<\/p>\n

\"block-cracking-in-tarmac\"Block cracking<\/h3>\n

Block cracking is where you get rectangular cracks appearing and can be fixed with a thin overlay or specific treatment of the crack. It’s caused by road workers placing the mix too dry, or it just happens as the road gets old. Unusually, it’s made worse by low traffic volumes.<\/p>\n

\"fatigue-cracking-tarmac\"Fatigue cracking<\/h3>\n

This type of cracking is also called alligator cracking because it creates lots of small cracks that look like reptile scales. It’s caused by excessive heavy traffic, poor drainage and a thin or weak surface or base. The tarmac needs to be taken up and replaced at full depth.<\/p>\n

\"longitudinal-cracking\"Longitudinal cracks<\/h3>\n

These cracks happen down or near to the centre of the road as they are mostly caused by poorly constructed paving joints. They are aggravated by daily temperature shifts and can also be caused by shrinkage or cracking in an underlying layer. Trapped water can make this worse. The cracks can be fixed with sealing with an asphalt emulsion.<\/p>\n

Slippage cracking<\/h3>\n

These are like a graze where a portion of the tarmac slips. If the mixture was laid with a high sand content, or some material such as water, dust or oil has got beneath the surface, there’s not enough grip between the surface layer and the base. It is often initially caused by a heavy vehicle turning or stopping suddenly where there’s an existing weakness. It needs to be fixed with a full depth patch<\/p>\n

\"pot-hole-with-puddle\"Pot holes<\/h3>\n

A pot hole starts with a small failure in the surface and gradually this is widened by the action of vehicles, frost, and running water as pieces around the edge of the hole become dislodged. They can be filled. Unlike cracks, pot holes can damage your vehicle’s suspension or tyres.<\/p>\n

\"tarmac-compression-puddles\"<\/p>\n

There are other pavement issues that can arise such as bleeding, loss of aggregate, settlement depressions where large puddles can form (like the image on the left), corrugations and rutting. Corrugations and rutting tend to happen more frequently on roads that are not sealed. All need to be fixed by using roadworks and this is covered in\u00a0Rule 288 in the Highway Code:<\/p>\n

\"hazard\"<\/h3>\n

When the \u2018Road Works Ahead\u2019 sign is displayed, you will need to be more watchful and look for additional signs providing more specific instructions. Observe all signs – they are there for your safety and the safety of road workers.<\/em><\/p>\n