CD Designs Blog
There are some changes afoot on this here website. We’ve recently completed a job lot of new case studies, covering pattern imprinted concrete driveways and pattern imprinted concrete patios that we’ve completed for clients. Depending on when you’re reading this blog, they first lot are either about to go live, or are up on the site already.
And there are more case studies coming. At Complete Driveway Designs we work hard to satisfy our customers, and that pays off: word of mouth means that we completed a lot of pattern imprinted concrete driveway installations every year. So we’ve got a lot of case studies to share with you. We’ll be regularly uploading new sets of photographs showing work we’ve completed.
We’re doing this so you have an idea of what to expect during the time we’re working at your property. And, of course, so you can see real life examples of finished pattern imprinted concrete driveways. We understand that you’re canny folk, and that no matter how much we tell you about the benefits of pattern imprinted concrete as a surfacing material, you’ll want to see photographs of the finished product.
So, keep checking our case studies to see examples of the quality of our work. And if you see anything that you really like, or have any questions about the design, installation or maintenance of pattern imprinted concrete driveways, please feel free to get in touch. We also offer free, no obligation quotations using a simple online form.
31st January 2011
One of the fundamental factors about crack prevention in concrete is for the contractor to ensure there is sound firm base to lay the concrete on. Typically it is recognised that you use a type1 MOTT (Ministry Of Transport Tested) as a standard sub-base. This ensures it meets the standards which is required on public roads. Type 1 is recognised as stone, which is 1 inch in size down to dust. Once compacted the dust and stone form a solid base. With current legislation we are encouraged to use a open aggregate with out the fines, This allows water to naturally soak away under the driveway.
This is something which is quite often a cause for dispute. We aim to place and compact our sub-base in accordance with our specification. This tends to be the minimum. If our specification is not to your standard, you can alter it to suit your needs at the time of quotation. Our specification is designed to withstand normal driveway traffic up to six tonne, and is usually adequate for most domestic driveways.
If the drive was to fracture then could it be because of inadequate sub-base? If the drive has sunk or slipped away then we could argue that the base has failed. Using the base we have put down, any fractures that have occurred have remained hairline. It is more likely fractures occur due to factors out lined in, “Cracking Factors outside our control.”
Concrete (Add Mixes)
The product it self is important and the specification is laid out in our “Domestic Driveway PIC Specification”. The cement content is important since this gives the concrete the specified minimum strength. Add mixtures which are used to improve the durability of the concrete also add extra benefits.
The first add mixture is the air-entrainment, this provides protection against frost. It does this by producing lots small bubbles like the inside of an aero, just on a lot smaller scale. The air bubbles allow for the normal expansion of water which the concrete may of absorbed, especially in freezing conditions. (Read “Salt And Concrete”, an exception to the rule) This helps concrete become a lot more durable in all weather conditions. This is a secondary protective measure, because we seal all our units with an impermeable acrylic sealer. So even if the sealer was to of become worn during periods of frost the concrete is still protected.
The second add mixture is the Polypropylene Fibres. These actually help inhibit (Prevent) the formation of cracks in concrete, whereas steel mesh only has functional value after the concrete has cracked. As well as adding strength to the concrete it reduces plastic cracking and enhances surface finish. This add mixture can be used without the need of using conventional steel re-enforcement in our slabs.
Crack Control Joints
With all our driveways it is necessary to incorporate crack control joints. As we know all concrete expands and contracts we need to allow for this. We can not prevent it from cracking but we can try and control it. The industry standard for spacing of our joints is for every inch of thickness of the concrete. We should allow 3ft (Just less than 1 meter). Therefore our slabs on a driveway should be cut up into sections less than 4m2 in area. This will and does help, allow for the initial drying shrinkage and thermal expansion and contraction associated with concrete.
We also have to take into consideration any integral items such as Manholes, walls, corners of house etc. Any intrusions in the concrete such as these will affect it when it shrinks during the early days of curing. It is recognised that more cuts within the pattern is better than too few.
When the design of the layout is formed, it is important to allow for expansion and contraction against wall and fences etc. The more “boxed in” our concrete is, the greater the chance of these stresses affecting it. Please be assured everything that can be done to minimise fracture will be done.
27th January 2011
A while ago, the Royal Mail group released the findings of some research that they’d carried out. This wasn’t your usual “top ten” list of home improvements… quite the opposite in fact. It was a list of the least desirable home improvements, according to the home owners they questioned.
What topped the list? Apparently, the home addition that people liked least was a “del-boy style” built in bar. Which surprises us, to be honest. Obviously, anything that’s “del-boy style” should probably be treated with caution. But we didn’t expect the result to be an interior bar. A poorly installed driveway, that we could understand.
A badly installed driveway looks terrible and isn’t fit for purpose. Conversely, a well installed pattern imprinted concrete driveway will make your property move attractive, will last for years, and will be a joy to park on. Take a look at our case studies for some examples of finished pattern imprinted concrete driveway installations.
The article contains a load more interesting facts and statistics; it’s available here. There are some interesting tips for people who are looking to do up their property in order to sell it. It’s worth a read. Of course, our number one tip would be: get in touch with Complete Driveway Designs, and get your driveway sorted ASAP.
26th January 2011
A recent bit of research we found claimed that grey is becoming an increasingly popular colour when it comes to home improvements. And we can see why; we suggest and install grey concrete for a number of our customers.
Don’t worry, we aren’t suggesting that we leave your pattern imprinted concrete driveway unfinished. We’re not talking about the natural grey colour you might immediately imagine when you think of concrete. We’re talking about grey colourants which we can add to concrete as part of the pattern imprinting process. These colours, sometimes combined with a release formula for extra contrast (picking out the fine details of the imprinted patterns), are attractive. Here’s an example of platinum silver, and here’s an example of classic grey. See what we mean?
Classic grey and platinum silver are amongst our most popular concrete colours. They’re subtle shades that don’t visually dominate, but are also very attractive. The perfect package, really.
If grey isn’t your cup of tea, we can colour pattern imprinted concrete a number of different shades. Combinations of colours and patterns lead to some really attractive results, and with our years of experience installing pattern imprinted concrete driveways, we’re the perfect people to advise you on what would suit your property.
25th January 2011
Cracking is a cause of complaint within the concrete industry. Our aim here is to educate the end user when cracking should be a cause for concern. Any, if not all, remedial work done over the ten years we have been in business, has been because of the aesthetics rather than structural failure. Cracking can not be prevented but it can be significantly reduced or controlled when the causes are taken into account and preventative steps are taken.
Public perception of cracking generally is “if it has happened, then the product has failed”. In the industry it is accepted it happens, a crack which is non- structural and less than 3/8 inch in height or separation, and not leaking water, it should be considered acceptable. It is in our best interest to ensure the end user is aware of this and more importantly when it should be of concern.
Before we look at the causes of cracking in concrete we must understand what concrete consists of, because it is the characteristics of these materials which induce cracking. Concrete consists of cement, sand, aggregates and water. When mixed together, the water hydrates the cement and a chemical reaction occurs bonding together the sand and aggregates.
After the concrete has hardened it is recognised that there are a number of factors out of our control, it is due to these that cracks occur. These are known as Physical, Chemical, Thermal and Structural factors.
This is something that all concrete can be affected by, Drying Shrinkage. To make concrete we have to use water to hydrate the cement and initiate the chemical reaction. More often than not more water is used than necessary to hydrate the cement. This is because we have to place the concrete using conventional methods i.e. Barrowing and raking and tamping. We work within the S2 range, which is between 50-90 slumps. (See PIC Specification) Without making concrete workable, it would not be possible to achieve the work we carry out.
Any of the excess water which is not used by the cement, will over time evaporate and work its way out of the concrete. As a result the mass of the concrete will reduce. If the mass reduces the concrete will contract. This type of contraction will create tension within the concrete and can and usually dose cause cracking.
Within our concrete slabs there are usually integral items which are crack inducing. E.g. manholes, walls, drain covers. Tension on corners as shrinkage occurs can and will usually lead to cracks forming. These cracks can occur as early as a few hours after the concrete has been placed or up to a few years.
Given the cause (Drying Shrinkage and Integral Items) and effect (Cracking) we can usually predict where the concrete will contract causing it to crack. As a result we place our crack control joints in these areas. It does not stop the concrete from cracking it helps us control where it cracks.
To make concrete a chemical reaction takes place, this reaction continues the full life of the concrete. The reaction progressively slows down once the concrete has hardened until about the 20 year mark, when it is thought it starts to deteriorate. Within the concrete other chemical reactions can take place which work adversely against the concrete and can be crack inducing. The corrosion of reinforcement is a process where steel in concrete starts to rust. When steel rusts it expands within the concrete and can sheer it apart.
The chemical process we are concerned about as end users is Alkali- Aggregate Reaction. The initial reaction poses no great danger to our concrete, but we as users can aggravate this process which will lead to rapid deterioration of our concrete over night. If salt was to be put on the concrete it can accelerate the process especially with the onset of sub-zero temperatures.(See Salt And Concrete) Since salt is usually used to melt snow/ice it is only used in the winter months when it is at its most destructive. Salt alone does little to damage the concrete, it is the moisture that it attracts that does the damage.
Temperature is an important factor which affects our concrete; it is the extremes of these temperatures which can cause the ageing/cracking. Internal concrete (concrete slabs inside buildings) will be subject to a lower range of temperatures, (between 10degreesC and 20 degrees C) therefore will be a lot less affected by expansion and contraction. Our driveways are subject to a range of temperatures reaching 30 degrees in the summer to -10 degrees in winter. These stresses can and will bring on unpredictable movement in the concrete.
In winter a strong frost for a prolong period of time will cause the concrete to contract. We can see this in the expansion joints we have created because they open up, likewise in summer they reduce in size, this happens all year long to a lot lesser extent. We may notice it most when it is at one extreme in temperature. In the winter months thermal contraction can contribute to shrinkage and cause unpredictable hair line fractures, which we have not planned for with our crack control joints.
We can’t predict the affects of our winters on the concrete, however we can ensure the base we put under our concrete is adequate to support it, therefore any fractures will remain only hair line and cosmetic.
Our concrete can be affected by accidental overloading, by a thing or vehicle. This can cause our concrete to crack so it is important that the usage is defined before the specification is designed. (See our PIC Specification for domestic driveways.)
Creep or settlement cracks is another cause for our concrete to crack. We excavate up to 200mm, the sub-grade soil below that is beyond our control.
To summarise both contractor and end user can play their part in crack prevention and deterioration of our concrete.
The contractor can ensure they work within the accepted slump range and ensure no more water is used in the concrete than necessary within the acceptable slump range. This will reduce any shrinkage within the concrete.
The End User can ensure no salt or chemicals be used or spilled on the drive and maintain the protective sealer.
To protect against any thermal expansion and contraction the contractor can ensure crack control joints are placed in the slab at the earliest possible opportunity after the concrete has hardened.
And finally the end user can ensure the driveway is only used for the purpose it was designed for, and not to over load it.
21st January 2011