CD Designs Blog
As the winter draws in, you might think of packing up your tools and leaving any pattern imprinted concrete driveway and pattern imprinted concrete patio work until next year, when spring starts to draw in. After all, the cold weather can have a lot of negative effects on concrete projects, making it hardly worth it?
We would say yes and no. The cold weather does present you with some challenges when installing concrete, but it is by no means impossible. Let’s look at some tips for beating Jack Frost back from your concrete!
When planning your winter concrete driveway installation, make sure you have everything ready to go. This includes all your materials, a properly prepared installation site, and weather protection such as insulation materials and heaters. The critical objective is making sure the concrete does not freeze, or get too cold for it to cure properly. This can happen if your concrete loses heat and moisture too quickly at the early stages.
* Using a lower slump concrete is good for cold weather, as it will reduce the necessary setting time and cut down on bleed water.
* Consider using accelerating admixtures or Type III Hi Early cement. These will get through the critical setting/curing periods quicker, so need protection for less time.
* Request a preheated mix of concrete from your supplier.
* Don’t use flyash-containing concrete if at all possible, as it will take longer to set/cure.
Next up, let’s look at the placement stage. To start with, make sure all snow and ice is removed from the concrete and sub-base. Use heaters to keep the sub-base above freezing temperatures, and try to keep the concrete itself between about 13 and 23 degrees centigrade.
After placement, don’t start finishing the concrete until bleed water has dispersed. At the same time, you should make sure that the concrete doesn’t dry out complete while curing. And never let ice form on your concrete while it is curing! Ideally you should keep the template of the concrete above 10 degrees centigrade using heated enclosures and/or insulating blankets for about three days to a week after pouring, and then keep it up to at least 5 degrees for four days after that.
One last tip — when you remove the heating/insulation, do it gradually, so the concrete doesn’t cool too rapidly (by 5 degrees or more per 24 hours).
16th November 2011
Although concrete is more often than not installed during the warmer months, it can indeed be poured, imprinted, set, and cure successfully during winter. Obviously, the process is a little more complicated than pouring in “ideal” weather (warm and dry), but it’s nothing that can’t be sorted out with some know-how and a few extra pieces of equipment.
Temperature affects the speed of the chemical reaction which makes concrete harden. At high temperatures (20C+) there is a risk that the reaction will take place too quickly. During winter the reverse is true; concrete laid without the necessary additional precautions could harden too slowly, and freshly poured concrete definitely shouldn’t be exposed to temperatures below 4C.
The problems that arise from installing concrete in winter can be solved through a combination of and awareness of a number of things. First (and this, to be honest, is just common sense) concrete should never be poured directly onto snow, ice, or frosted or frozen ground.
Secondly, the concrete being poured in winter usually has a slightly drier mix than normal concrete. This “low slump” mix helps to minimize any risk of complications through bleed water, and water in the mix as it sets, freezing due to low temperatures.
Thirdly, attention needs to be paid to the finishing of the concrete, so no water remains on its surface. This is an important stage in any concrete installation, and one in which you’ll definitely reap the benefits of using skilled and experienced contractors.
Finally, after concrete has been laid and finished, and if the temperature is low enough to make it necessary, it should be protected by covering it with plastic sheeting and some form of insulating material, ideally dedicated insulated blankets fit for the task. This will allow the concrete to cure properly, and ensure that consistently low temperatures don’t retard the hardening process that gives concrete its impressive strength and durability.
11th January 2010