Exposed Aggregate Concrete

Top 3 Concrete Projects

Continuing on from our last articles for our top 3 decorative resurfacing projects, here we are with our top 3 concrete projects that we have completed.

I’ve selected the following projects somewhat due to the size of the project, but also because of the methods in which they were completed, overcoming obstacles and having everything run smoothly through solid organisational methods.

Exposed Aggregate & Plain Grey Unit Surrounds Paradise Point

Location: Paradise Point
Size: 140sqm
Value: $17000.00

I’ve chosen this project not due to the size of the work, being only 140sqm it is considered a relatively small job, but the extent of manual labour required to complete the project was exhausting.

Upon original inspection of this project we were confronted with both sides of the unit complex sub-grade being extremely low, along with the rear section where the new water tank was to go. Also the front driveway was at a high rise from the road to the garage entries, also having an existing driveway in place that needed to be removed before pouring the new driveway.

First things first on this one, we ordered 20m.cub of 20mm road base to the front of the property, due to the limited access up the sides, (just enough room for a wheel barrow), we proceeded to hand wheel in all 20m.cub of fill to raise the side sub-grade the required 300mm~ higher ready for new concrete. Given the area was so skinny and long as well, we also needed to accommodate for garden areas and falls on the concrete to take the water to the garden beds, where drainage was installed to remove the water from site.

After some heavy days and lots of sweat and swearing, the sides were filled up and we brought in the machines to remove the old driveway and sub-grade it ready for the new pour.

We pumped in the side pathways first in plain grey concrete, along with the rear water tank. Surprisingly this pour went very smoothly. Typically when pouring areas like this it is difficult getting access, especially considering the multiple fall points that needed to be leveled every few meters to make sure of water run off. With a nice soft brush finish we then returned the next day to tackle the driveway.

The driveway was a relatively simple pour, but given the gradient a lot of care needed to be taken to keep both sides looking symmetrical, which of course we accomplished with some due care. We finished off here washing off the salt and pepper exposed aggregate nicely and saw cutting the control joints right through with an acid clean on the aggregate.

This project being 140sqm would typically take us 2 days to complete on a regular project, however, we were on this project for just over a week. That gives a little idea of just how much extra manual labour was required. We don’t mind working hard as concreters, in fact, we welcome it a lot of the time, but I have to admit this project was above and beyond what we’re used to.

Exposed Aggregate Driveway & Surrounds Helensvale

Location: Helensvale
Size: 400sqm
Value: $30700.00

Second on our top concreting project list is the exposed aggregate driveway and surrounds we placed at Helensvale a while back. I’ve chosen this project due to it’s size, limited and awkward access, along with the time of year and weather that we encountered.

Our client was required plain grey concrete to the rear and side of the property in 2.0m wide pathways, along with a salt and pepper driveway with 4 car wide parking at the top, slowly bending back around and tapering down to the property entrance.

The rear of the property was retained behind the house and at the bottom of a hill, which received large amounts of water when it rained. We decided to install 5x pit drains through here and basically fall all of the concrete in “wash pit” fashion towards these drains. Once we got to the side of the house, we installed a ramp tapering down the hill, then finally all the way around to join the new exposed driveway we were to place.

The plain concrete at the back for the paths needed to be pumped as there was no other access, and given the amount of falls that needed to be hand done throughout the pour, we decided to break it down into 2 pours. After everything was prepped ready to go, the rains started. Having delayed a few days with bad weather and falling behind schedule, we had booked concrete on a Thursday morning to pour the first section, only to have horribly wet and hot weather the night before continuing into the morning. We postponed the first pour until midday, which is something we basically never do, but we had to do what we had to do. With the hot and stormy weather, couple with concrete from Hytec which has a habit of going off very quickly, myself and the boys busted our tails and only just got back onto the concrete in time to give it a nice brush finish.

We returned the next day to complete the side path of the house with the ramp and decided to call it a week to return the following and get started on the driveway.

The driveway was a somewhat easier affair, with the only problems being the actual size of the project. We broke the driveway down into 3 pours over the next week, wanting to make sure we broke the pours off with construction joints as we went due to it’s expanse.

Finishing off the project with saw cutting the control and acid cleaning the aggregate, our clients were grateful enough for our work to buy a very nice bottle of scotch, of which we opened it up and enjoyed it with them for a few good stories and tall tales.

Plain Concrete Hinterland Driveway Molendinar

Location: Molendinar
Size: 375sqm
Value: $22000.00

Finishing off our top 3 concrete projects was our plain grey hinterland driveway at Molendinar. I’ve chosen this job because it was one of those projects that had a good amount of size to it, but also displays what good concreters can achieve when things go well.

Faced with a 125m long gravel driveway leading from the road to the house, our client was requiring a 3m wide concrete installation that they had been waiting 15 years to go ahead with. With only a few sharp corners, it was one of those projects that you just start at the house and keep working your way out.

After spending a few hours with the machine to sub-grade the existing gravel making it smooth and ready for concrete, we proceeded to box up the first pour of this project which would be around 90Lm long. All the steel was cut to size and left beside the job all the way along, we then returned the next day to begin pouring the concrete.

As we reversed the trucks along the driveway, we proceeded to shoot out the concrete over the steel that we were placing as we went, having 2 men in the concrete screeding and raking, 1 labourer on the shoot and two men falling back finishing. We finished off the first pour with a trowel machine finish with a light broom for some traction and found ourselves with beer in hand setting up the next days pour by around 12pm.

The second days pour was much shorter, but being up a relatively steep incline it still made us work quite hard for the result. Finishing off this pour up the hill, this time no trowel machine as it was too steep, the boys had it edged, troweled and broomed for a going home time around 1pm.

I returned the following day to run our saw cut control joints right along and pick up all the timber from site, leaving it a nice little 4 day project that ran as smoothly as you can get it.

If you’ve got a project coming up, we’d love to hear from you. We take a lot of pride in our work and you won’t find a more professional outfit in the residential sector. Give us a call today for an obligation free quotation and advice on your job, you won’t be dissapointed.

Concrete Resurfacing Robina

Top 3 Concrete Resurfacing Projects

I thought I might start off a couple of articles portraying our top 3 projects for the areas of firstly Covacrete Decorative Resurfacing, which this article will entail, then following in a day or so out top 3 concrete projects.

The main reason why each entry has been chosen for each category is the level of satisfaction that I personally received from that particular project. Each entry will have an outline of the project and what was involved, plus a detailed walk through of the thought process behind the end designs, plus also during their installation to keep things on track.

So without further ado, please find below our top 3 Decorative Concrete Resurfacing projects.

Swirl and Patch Resurfacing at Robina

Location: Robina
Size: 220sqm
Value: $11000.00

I’ve chosen this project to be first up due to the final result achieved for a complete freehand project. When in talks initially with our client, they were unsure exactly in what direction they wanted to head. After presenting them with many different options, I presented to them what we have done previously with sandstone mock finishing, but with a custom edge. Our clients property backed onto a lake and their pool area was quite pretty, so we had the vision of creating a watery feel to the entire surrounds and driveway.

I asked my client for a little faith in the design and advised them roughly of what the actual outcome would be, of which they were excited about. The existing concrete was exposed aggregate concrete right throughout, which of course had to be based with modified covacrete to create a nice smooth finish to the concrete surface for us to apply the pretty stuff. After completing this and repairing the areas that needed repairing we were set to complete the spray.

Standing back on each section and taping large triangular sections of the concrete surface, trying to get all the odd corners and angles to blend into each other to appear as one large piece of concrete all working together in harmony. We then proceeded with the two main coats of our main colour.

From here the tricky part began. With this finish process each section needs to be blocked off from the individual section that you are applying the patterning too. This alone is a time restricted process, especially when trying to keep everything clean from over spray. We proceeded to apply our swirls firstly to the entire area, standing back after each section was applied looking for a visual contrast of where to apply the next swirling.

After moving through the entire swirling process, we then return to block off each section to apply some light spray patching to the corners and randomly throughout the remaining triangle areas. As always with this process there was some drips and over sprays, so finally we finished off returning with our main colour to patch up the mistakes, then finally finish the project off with 2 coats of sealer.

I really loved this project due to us having a set plan of attack on what we foresaw the outcome to be like, along with hitting the mark at the end for a beautiful, ocean feel to our clients pool surrounds and driveway.

Custom Resurfacing Monterey Keys

Location: Monterey Keys
Size: 120sqm
Value: $7250.00

Second on our top 3 list is the recent concrete resurfacing project at Monterey Keys. Upon quoting this job we were presented with a tile base that was all cracked up and looked pretty bad. We got a lot of satisfaction from this project because removing tiles and grinding back tile glue is always a bit of a nightmare and more often than not, a real bugger to lift the tiles up.

With only a limited amount of whinging, I decided to bring in a fellow concreter who has a dingo digger, using him to pick all the broken tiles up for us after we’d jack hammered them up from the concrete. I have to say this is the first time I’ve used this method, typically just relying on manual labour to get the job completed. Guess what? It worked a treat. 120sqm of tiles jack hammered up and removed from site in roughly half a days work, not bad if I say so myself.

Next was the floor grinding of the tile glue to reveal the concrete surface to bond to with our resurfacing products. After spending basically a full day grinding, we had removed 150kg~ of tile glue from the surface, which was all swept up into a tarp and removed from site in a big dusty mesh everywhere (of which we cleaned up nicely of course).

Our client was after something unique and different from the every day grind of all the other covacrete finishes up their street, so we decided to put together a 3 colour design with large taped out areas attempting to blend both the wide driveway and pathway together whilst seamlessly blending with the house.

As you can see from the photos everything matched nearly perfectly, from the colours to the angles and how it all blended together. This was another project where our clients gave us some leeway with the design and succeeded with flying colours (no pun intended).

Contemporary Resurfacing Nerang

Location: Nerang
Size: 120sqm
Value: $6400.00

Last but not least of our top 3 is a project we completed in Nerang a year or so ago. I’ve chosen this project not only for the outcome which is very fitting, but again also because our client gave us some leeway with the design choice and let us work out magic.

This was another project where upon quoting the project it kind of made us twitch a bit with what had previously been completed by the previous owners of the property. I discussed with our client the options that we had and upon handing over the price, advised that it’ll be a challenge, but we’re up for the task.

The previous owner had done things on the cheap. At one stage it had had other sections added that needed to be removed and replaced, also leaving one of these sections out for a new garden area. The existing concrete had also been painted with I’m sure what seemed at the time a great coloured finish, only to then be repainted by the same owner again without removing the first coating of paint. The second topping clearly wasn’t up to their standards, so guess what? A third coating of a different design was applied as well, again without the removing the previous two coatings……..which didn’t work out either. You’d think after failing twice previously you’d give up the ghost and try something different? Well at least the new owners (our clients), had enough brains to change what wasn’t working.

We set about with our floor and hand grinders for two days removing all the layers of paint from the surface, then followed that with a heavy acid wash and crack repairing, all ready for our coatings to be applied.

After base coating we then taped down a 100mm border around the perimeter, with inserts going approximately 2/3rds along from the sides into the driveway following the control joints that were existing. We then taped these borders into a tile pattern 300mm long and sprayed these sections openly with our darker colouring.

From here each of these borders and inserts were taped off so the main surfacing spray did not go onto them, which of course is relatively time consuming, but nothing we don’t have the technology for.

From here we applied our main coating, followed by 2 flecks to add some depth to the project, then removed all the taping to reveal a really sharp, textured contemporary feel to the property matching the newly rendered walls.

As you might be able to tell, we take a great deal of pride in our decorative concrete resurfacing projects. To us they’re not just another paycheque, rather an opportunity to tickle our creative brains and create something new, from old.

Exposed Aggregate Concrete

Matching Exposed Aggregates

As with most entries I make on this website in regards to concrete and contracting, they generally come about through my day to day experiences with projects and clients expectations.

One topic that comes up more often than not, are clients wanting to match their existing exposed aggregate concrete that they already have placed, with the new exposed aggregate concrete being placed.

It is correct to consider exposed aggregate stones in the same relative category as decorative resurfacing colours and colours for your colour through concrete. It is a natural product that is not calculated to precise measurements during mixing at the plant. Quite literally, the aggregates are mixed with the concrete by machinery and conveyor belts typically by weight, meaning, that no two loads of exposed aggregate will be exactly the same.

In saying this, you can trust (on most occasions), that when pouring a driveway for instance, where two or more truck loads of concrete are required, that the multiple loads supplied on that same day will be close enough to a match together that it is unnoticeable to both client and contractor. However, I have come across the rare occasion where we have poured a selected exposed aggregate, only to return a week later to pour the remaining part of the job, (with of course the same selection of stone), and have it look different enough that it was noticeable. The project itself still looked fantastic as a whole, but the blending of stone was different.

Now this is all well and good when we are talking about a singular project that we are completing at a given time. Even with a difference coming through, because the two parts of concrete are poured within a given time frame, along with being supplied by the same company, there isn’t a problem at all.

From here though is where we enter the problematic area. Lets say for instance you as the client, have had your exposed aggregate poured previously, for sake of conversation lets say it was 12 months ago. Now you are after some new exposed aggregate to be poured adjoining the existing slab. You’ve done the right thing, remembered who the company was supplying the stone and exactly what it is called, even with these measures in place, there is absolutely not guarantee that your new stone will be the same blended mix as the one that was poured a year ago.

Also you need to take into consideration the after a few months, concrete starts to build up dirt and mold in the actual cement, which typically starts to darken you cement within the concrete (seen between the stones). Then when we place the new exposed aggregate concrete, as normal, when cured it comes out a very white, bright colour. This will make the two sections of concrete appear different overall when looking at them together. This aspect of course will get better over time as the new concrete starts to get dirty and mold as well, so time is your friend in this case.

Now we get to the really tricky part. You’ve had your concrete poured a year ago and you’ve forgotten what company supplied it and what it’s name was…..This side of things is considered a bridge too far with matching. Yes, you can have your contractor look over your concrete and advise you what he/she thinks is the “best match”, you can also have a sales rep come out to site to also advise you on their thoughts, but at the end of the day it is a calculated guess and more often than not will be a wrong guess.

Our exposed aggregate concrete we supply comes in sections separated sometimes by 10%. For example, “Dalmation” (Salt and Pepper), concrete starts at 10% white stone and goes up in 10% intervals right up to 90%. So if we’re trying to match your existing “Dalmation” concrete and you can’t remember what percentage it was, we are basically then taking a guess at the problem. It might not sound much only being out by 20% of the white stone mix, but this will make the difference stand out dramatically when the two concrete’s are next to each other.

With all this said, I guess at the end of the day if you follow a few simple guidelines you can at least be assured that the best efforts are made to match your concrete…..

  1. Write down the name of the concrete exactly when you have it poured
  2. Write down the supplying company of your concrete
  3. If possible, try and complete all exposed aggregate at the same time

If you haven’t or couldn’t do these three steps…..

  1. Contact sales rep and contractor for their advice with samples
  2. Understand that the two concretes will look different
  3. Or….Choose a different aggregate to try and contrast rather than matching

Be reasonable with your expectations. We are dealing with natural products that are not mixed like paint through a computer, there is always room for error when matching these natural products and as with all colour and stone options, typically, the contractor should not have to take any responsibility for variations in these products.

Concrete Strength

Strengthening Your Concrete

A lot of clients I speak to ask about strengthening their concrete installation by making their concrete thicker throughout, but this method isn’t always the best option for making your concrete stronger.

There are more things you need to consider rather than just thickening the depth of concrete.

Now this isn’t to say that your concrete won’t be stronger by thickening it, but you need to consider the weight of the concrete upon the ground that it is sitting on. Concrete is extremely strong in compression and relatively weak in tension. Compression obviously being the sheer weight pressing straight down on the concrete, as opposed to tension being allowing the concrete to flex along it’s axis.

If you are considering making your concrete thicker simply because you need to drive heavy vehicles over it, then the difference between say 100mm of concrete and 125mm of concrete is negligible, as typically 100mm of concrete will handle the same weight in compression as 125mm will handle.

The main areas to attack firstly in strengthening your concrete I will explain now in better detail below. The trick is to initially strengthen the concrete in tension, then worry about the compression factor lastly.

Increasing Thickness of Steel
Steel Reinforcing acts as the backbone for the concrete under tension. It is used primarily to control cracking if/when it occurs by not allowing the cracks to pull apart and become structural. On a standard driveway installation for example, you can expect a contractor to install 6.2mm steel mesh throughout (hopefully chaired into the concrete). A good first step to improving the strength of your concrete under tension, is by installing a thicker version of reinforcing anywhere from 7.2mm to 9.2mm. A house slab for instance will usually have 8.2mm reinforcing installed. Thicker steel has less “bend” if you will throughout it’s horizontal line, which helps holding the concrete from being allowed to move along it’s horizontal line as much, therefor limiting the tension.

Concrete Steel

Thickening Beams / Footings
As you can probably imagine by looking at a slab of concrete, it is along the edges that the concrete is most at risk from moving up and down along the horizon (tension). Concrete, as a general rule of thumb as well, tends to want to tension crack roughly every 2-6m of laid concrete. It used to be if you’re using 6.2mm mesh that you need controls every 2.4m, 7.2mm mesh you need controls every 3.0m, 8.2mm mesh with controls every 4.0m then 9.2mm mesh controls every 6.0m. This I put into memory a very long time ago as per Australian Standards, so don’t check me up on this as they’ve most likely changed since then, although they are still a good reference point to work from. When I talk about “controls” they can either be saw or tool cut control joints, but also a thickening beam or footing can do the job just as effectively. By installing thickening beams or footings along your perimeter, as well as throughout the middle of your slab, you are effectively adding more strength in base compression whilst restricting the concrete from being able to “tension”.

Concrete Beams

Maintaining Course Aggregate Size
The course (or large) aggregate within your concrete is kind of the backbone of your concrete. It acts as the main property of your concrete that all the other properties (cement, fine aggregates etc), bond to to form your concrete. Standard concrete is installed with 20mm course aggregate, this is considered to be the strongest standard for the size of the aggregate. From here, contractors can install smaller aggregate of 10mm depending on the installation, usually though when this happens, the MPA rating is also increased to assist with de-strengthening your concrete. There is also an option getting around of “reduced line” concrete, which has approximately 30% less aggregate through your concrete, plus also a maximum size of 7-10mm course aggregate….if you ever have a contractor looking to install reduced line concrete, sack him/her immediately and find someone who is serious about supplying you a proper installation.

Concrete Aggregate

Ground Compaction / Subgrade
Typically the most common reason for your concrete cracking under tension is by the ground underneath the concrete moving under the weight of the installation. Upon request, an contractor can bring in a better sub-grade material than what is already on your site, typically being good fill sand, crusher dust or even 20mm road base depending on the depth of fill that is needed. Then from there, have this sub-grade compactor with a plate compactor making sure the ground is as solid as it can be to assist with holding that new concrete in one place.

Concrete Compactor

Further, typically when a professional contractor is out to install your project, there are base standards for your new concrete installation. The contractor is usually seeing what the underlying ground is like and endeavoring to install your new concrete to a good, solid standard for strength. Concrete has been around since the Romans, and for instance, having your concrete installed by Walker Concreting & Resurfacing, you will receive what is considered “the norm” for a good installation.

The factors I have listed above are considered above and beyond the standard requirements and are for clients who require that little bit of extra piece of mind with their concrete installation.

After the above factors have been met, you can then start talking about thickening your concrete installation, to assist with “compression” of the concrete. A good rule of thumb when thinking about “compression”, is taking a look at Hoover Dam in America, it was specifically designed in an arc against the force of the Colorado River because the compression strength with the water constantly pressing against it is when it’s at it’s strongest.

As always, by using these guidelines to strengthen your concrete, you can be assured of a structurally solid installation. This is not a guarantee against cracking, as cracking and concrete go hand in hand. But, these processes’s will assist in making sure your installation is there to last a lifetime.

Concrete Resurfacing

Covacrete Resurfacing Process

Here I’m going to go through the nuts and bolts of a typical Decorative Concrete Resurfacing Project (Covacrete). The following articles consists of what I consider to be base standard with your application of the process when you choose Walker Concreting & Resurfacing to complete you project.

First things first. Typically, when we get to your concrete that you require to be resurfaced, lets be honest, it’s usually in pretty bad shape. It’s either a dirty old moulded surface, or has been previously sealed or painted in it’s history and all these things will hinder the bonding of our new Covacrete application.

Majority of the time we will complete either a heavy or light surface grind of your concrete to remove all these foreign properties and make sure that our new Covacrete product is bonding directly to the natural concrete surface. This is completed with a walk behind floor grinder and also a 9″ hand grinder for the tight to reach corners.

Surface Grinding

Concrete Floor Grinding

Next up is giving your concrete surface a nice, heavy bath in hydrochloric acid.

Using approximately 3-4 Liters in a 10 Liter watering can, your concrete surface is covered thoroughly with the acid and it is allowed to soak right into the concrete and all the pigments on the surface.

This helps to break up any remaining unwanted particles on the surface, but also lets us eat into the surface finding a more appealing structure to adhere our Covacrete to when applying it.

Acid Bath

Acid

After the hydrochloric acid has been applied and allowed to soak in for several minutes, we then attack the surface with a high powered gurnei to further remove anything we don’t want on that surface.

The combination of acid and pressure washing loosens up the surface particles even more so and again helps us get down to the bare bones of the concrete for a better Covacrete application.

Pressure Washing

Pressure Washing

Next we take care of the cracks. Cracks repair varies depending on what type of cracking it is, I’ve explained all this in another article, I really should link it here, but you’ll just have to do some research yourself :).

For standard hairline cracks that are non structural, then we simply go about grinding out these cracks thoroughly, then applying our “secret sauce” crack repair product to them. The idea behind this is that your concrete has already tensioned and cracked along it’s weak point and the crack is being held together by the steel. So if we expand that crack through grinding, then fill the area, then technically the crack should not pull apart any farther and not come back through.

This of course is not a fool proof system, although we do our best, and most of the time succeed, these little buggers do sometimes come back through again, but, typically only a hairline crack will show.

If you have structural cracking, then realistically your only option is to remove sections of your concrete where the problem is, and replace that section with new concrete before applying any Covacrete.

Crack Repairing

Crack Repair

Covacrete Application

Base Coating
After priming your newly cleaned surface, our next step for your sexy new concrete surface is applying our base coating. This stage of the application will allow us to level all of your surface smooth and give us a good initial coating of our products. Covacrete comes standard in “Ivory” colour, but there is the option of adding in a colour to your base coating. Your base coat will be visible as the “grout lines” if you will in your taped patterning. Colouring the base coat works really well when applying a lighter colour top coating of Covacrete and using a dark base to make those lines contrast well.

Taped Patterning
From here we apply our taped patterning to your hearts desire. You might decide you want diamond or tiled patterns, maybe borders, tile inserts or full showpiece compass’s installed. The world is your oyster here and we love getting a little creative with our patterns.

Top Coatings
After all our patterns have been completed, we then proceed with the fun stuff. Air compressor pumped up and hopper oiled, we begin spraying on your top coatings of Covacrete in the colour / colours that you have chosen. The top coatings are applied with a minimum of 2 coatings, with the initial run being more of a “covering” application and the later coatings for the even application and good looks.

Decorative Patterning
To finish up the spraying we then apply your decorative aspect to add contrast and depth to your installation. You might choose to simply apply a few different colour flecks to the surface or go all out with Sandstone Swirls and hand done patching. Obviously pricing matches the level of detailing we go into, but as always, we’re here to give our clients what they require and consider ourselves top of the game in the artistic side of things.

Finishing Up
From here, after all the spraying has been completed, we then rip off all the taping that we applied earlier, remove all the tape from your walls, blow off the surface, then proceed to apply 2 applications of high grade acrylic sealer to protect your new surface and give it a lovely shine in the process.

If you’re interested in our services for concrete resurfacing, give us a call soon about your next project. You’ll love what we have to offer and our professionalism and service is beyond reproach.

Exposed Aggregate Concrete

Exposed Concrete Options

Exposed Aggregate Concrete is a very popular residential concrete application on the Gold Coast. With many different options for stone colours, there is always a choice that suits your natural surroundings of your house. However, Exposed Aggregate Concrete doesn’t always have to be just a standard plain grey concrete with different coloured aggregates. It can be mixed up in a few different ways to really create something unique for your property.

Standard Installation

Installation of exposed aggregate is usually quite a simple process for a contractor with enough experience in it’s application. Exposed is all about timing by your contractor, it takes skill and experience to know the timings of each stage of it’s placement. Typically after placing and screeding off your Exposed Concrete, it is then floated and the surface is continually worked to bed and flatten the stone correctly. When the timing is right, the surface is then retarded by with Raw Sugar or a chemical compound specific to this requirement, then again, when the timing is correct, the surface will be washed off revealing the coloured stones underneath.

Variation 1: Inserts / Borders

One way of mixing things up is with inserts and borders. As you can see in the image installation of plain coloured concrete with exposed aggregate has been installed for the middle section, followed by the same aggregate being installed surrounding it with a simple colour through the concrete to change it up. You can also do this with borders, plain concrete with a colour and also inserting tiles and pavers directly into the concrete.

Exposed Aggregate Concrete

Variation 2: Colour Through Concrete

One of the simplest ways to change things up is to add a colour oxide through your concrete during the mixing stage. The Oxide mixes through the entire concrete body and once we wash off the surface, with the right choice in colour, contrasts against the stone choice of our clients. There area many different options for colouring your concrete, please check out our Colour Charts under Customer Relations to have a look.

Exposed Aggregate Concrete

Variation 3: Polishing to Expose

Our final way of finishing your Exposed Aggregate Concrete is to place the concrete as per normal, but instead of washing off the surface during placement, we will wait for the concrete to set and cure, then return with our grinding and polishing equipment to remove the surface revealing the stones, along with flattening the stones along the surface for a very sleek, modern finish. At times this finish can be slippery when wet, however we can add texture to the surface within the sealer to assist with this.

Polished Exposed Aggregate

If you’re thinking about putting in Exposed Aggregate Concrete for you new driveway or other installation, have a chat with us and think outside the box. With these few, simple process’s we can create something unique that not everyone in your neighbourhood already has installed.

Concrete pour

Properties of Concrete

Ever wonder about the basic materials that are mixed to make your concrete? In this article I’ll be going through each of the main materials and what part they play in your concrete.

Cement

Cement

Cement in your concrete is essentially a binding material that forms as a glue for the other materials in your concrete.
It is made by combining silicon, aluminium, iron, calcium, chalk, clay, slate and limestone with other chemicals in a controlled mixture. When combined and water is added, it reacts with the other materials to heat and harden, binding the fine and large aggregate together that make up your solid concrete structure.

Fine Aggregates

Concrete Sand

The fine aggregate (sand), is a very fine material which can assist concrete to solidify, giving the necessary strength required. Sand can fill up the pores or voids inside the concrete which is also a contributing factor for the strength of the concrete. Its considerable hardness and resistant to weathering makes it the perfect material for the mixture.

Course Aggregates

Aggregates

Course aggregates are the larger stones in your concrete mix. They are also considered somewhat of a filler material making your concrete mix stretch further, but they are also one of the main strengthening properties of your concrete. 20mm aggregate is considered the base size and has the best strength properties. Once you lower the size of the large aggregates to 10mm you are weakening the strength of your concrete, so typically to make up for this you MPA rating will be raised (amount of cement) to counter the loss in aggregate. There is also an option for “reduced line” aggregate, which is basically a reduced mixture of large aggregates that are used. Personally, I would never place reduced line concrete as it’s strength properties are far below anything I would be confident in placing and standing behind as a contractor.

Water

Concrete Water

Water in the mix makes the concrete workable during placement. During the setting process, the cement materials start to super heat, which in turn makes the water start to evaporate and be forced out of the concrete mix, making all the properties start to harden and bind together. As a general rule of thumb, it will take only a few hours for the water to evaporate enough for the concrete to begin to harden to the point it can be finished and by the next day, enough water has removed from the concrete to harden enough to walk on without damaging it. It can take up to a month for 100mm concrete to cure properly with all the water evaporating from within the concrete.

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Concrete Crack

A Tale of 3 Cracks

Cracks, cracks bloody cracks.

They’re ugly, unwanted and sometimes a sign that your concrete is falling apart. But not always….

We as concreters do very little during an installation to prevent cracking of the concrete, rather, we put a lot of effort into controlling that cracking.

  • With proper installation of steel reinforcing, we aim to control the crack from being able to pull apart from itself.
  • Installation of Abel Flex allows for the concrete to move hard against another solid structure, which in turn removes excess tension from the slab attempting to help the concrete crack less.
  • Control joints create a weak point in the concrete depth which it is hoped, that the concrete when under tension will find the weakest spot to crack along inside our cut or tooled line, subsequently controlling where the concrete cracks.
  • Installation of crack inducers are installed under the concrete (usually where a control joint will be cut, to again assist in this area being a weaker spot to find under tension.

As you can see, the majority of tactics we undertake to combat cracking, are actually for controlling the cracking and not stopping it. It is fundamentally shallow thinking to believe your concrete, being a solid structure placed on soft ground, will not find a point where the tension is too great and over the length of the concrete and cause a fault.

Apart from the ways we as contractors go about your structural project, lets go into a little more detail of the 3 main types of cracking and how serious they actually are.

Shrinkage Cracks

These cracks occur during the pour due to the concrete surface setting too quickly. The water evaporates to fast out of your materials, then the surface sets too quickly causing it to shrink and crack.

These cracks usually happen when pouring on extremely hot days or overly windy days. Unfortunately, there is very little a contractor can do to stop and fix this once it is happening. The only real two ways to go about this is to use an Alcohol based vapor on the surface to re-add some moisture, then continuing to work the surface keeping the small cracks closed and holding together.

These cracks are not structurally a problem for your concrete, they are unfortunate, but will remain small hairline spiderweb cracks without pulling further apart.

Concrete Crack

Non Structural Cracking

Non structural cracking is where your concrete has started to tension either from the ground underneath moving under the weight of the concrete, or by heavy vehicles / items being placed on the concrete.

This type of cracking is called non structural because although the concrete itself is cracking, our preventative and controlling measures are working and the crack is not separating any further.

There is typically no need for any rectification work for this type of cracking, as they are considered normal and just unfortunate that they haven’t found the control joints to crack along that have been installed.

Concrete Crack

Structural Cracking

Structural cracking is caused by the same reasons I mentioned in “non structural cracking”, however in difference, these cracks are not being controlled by our preventative measures and are not only beginning to pull apart further than they should, they can lead to lifting or dropping of the two section of concrete surrounding the crack and have serious consequences for your concrete slab.

If you have this type of cracking occur, it is normally due to failure during the installation by the contractor and they must be dealt with immediately to rectify the problem.

Concrete Crack

After you’ve had your new concrete installed you get some cracking, take a little further investigation into what kind of cracking it is.

Most of the time, cracking in concrete is considered normal however unfortunate it is to both client and contractor, nobody likes to see them.

If you do however, notice that your cracking is starting to pull apart more than say a $1 coin in width, then it could be structural. Give you installer a call to come and inspect and if required, for rectification to begin.

Satisfaction Blog

Job Satisfaction

A lot of people seem to have a misconception about concrete and concreters, sometimes thinking of it as a dull industry with just a lot of hard, physical work involved. Of course this can be true from time to time, but, unless you’re in the industry you won’t get to see the job satisfaction that is brought about after completing a project, especially a decorative project or something freehand.

I can personally look back on the projects that I/we undertake at Walker Concreting & Resurfacing and recall at least 9/10 jobs where I’ve actually stood back when the work was complete looking over the job and feeling very proud of myself and the boys for what we have accomplished.

Here I’ll go through a few of the things in detail which make our industry so rewarding for the men and women who ply their trade within.

Physically Hard Work

First things first. A lot of the time, concreters aren’t drawn to this trade for lack of better options. We’re a funny breed of people who would rather be out getting our hands dirty and having sweat over the brow as opposed to sitting in an office with a tie on having to shave every day to keep up appearances.

Concreting can be a very physical line of work for a good part of it. Everything is heavy, the steel, demolition, new concrete, it pushes our bodies with everything we seem to touch.

This brings about a sense of accomplishment and pride by the end of the job. Sitting back and going through in your head exactly how much materials you have moved and placed by hand is not something anybody can just come and do. It not only takes a fit, strong person to complete the work, but also years of training and expertise in knowing exactly how to handle the materials to get things right (and make it a bit easier on the body as well).

Pouring Concrete

Winning Projects

Apart from all the work that goes into the backend of the business through advertising and years of good, quality work provided to gain a good reputation, the quoting process of a project is extremely important and takes a lot of work to make yourself stand out from the competition.

Firstly, getting that call from a potential client, then going out to inspect the work that is required, to writing up the quotation in detail and outlining the entire project’s schedule to expect to complete it in. Then finally providing our clients with website information, address’s to inspect our work and several other items to make yourself stand out.

Having all of this information come together properly and having our client call us to approve our quotation to pick us above our competition is extremely satisfying. It means we have done everything right in gaining confidence in our client to have the knowledge that we can complete their work to the standards they require….being put first among our peers who competed with us.

Quote Sample

Project management

Organising a concrete project can be relatively challenging. Not only are there many things to bring to site to complete the work, but it all needs to arrive at the right time to make sure the project runs smoothly, and we make the required profit from the job. Time is money, and if something isn’t there when it’s meant to be, can hold the project up costing dollars.

Disregarding the the preparation stages of a project, I’ll just run through what a typically pour would be like getting things managed correctly.

First of all there are several men/women working on the project for the day, these people need to be organised to turn up on time and to bring the right equipment with them.

From there, there may be a concrete pump that needs to be pre-organised with a specific time they need to turn up. We also have concrete delivery of 3-4 trucks or more to complete your project, these also need to not only turn up on time, but have certain separations between each truck allowing for proper placement without waiting time being charged.

As the concrete is being placed, heights and falls need to be strictly adhered to to allow for a good installation, this all needs to be completed in a certain time frame as the concrete is going off as soon as it is mixed, so we’re on the clock.

When the concrete has been placed, we need to then keep a keen eye on what the concrete is doing as it is our boss for the day and we work to it’s requirements. Some places go off quicker than other, as well as all the edging and floating that needs to be done yet. It takes an experienced eye to keep up with concrete and not start falling behind it….as well as physically hard work of course.

Finally finishing the concrete which is again usually done while chasing it on a time frame. That surface needs to look good and there’s only a relatively small window to make sure it happens.

When all this works out well and we have done our managing correctly for times and materials, it’s very rewarding seeing the results of our work.

Concrete Carrara

Decorative Applications

Decorative concrete and decorative resurfacing is by far the most rewarding part of this line of work. From exposed aggregate to covacrete resurfacing, the results speak for themselves.

Years of practice in our trade lead to expertise in these sectors. Exposed aggregate for instance can be tricky at times getting the timing right, being ultra careful with your screed as to not leave screed lines in the surface, to working the surface and timing the sugar correctly, every part of exposed aggregate installation is important and we only see the success of our installation during the final stages of washing off the concrete.

When we are decorative resurfacing, we are taking an old, worn out structure of concrete and turning it into something sharp, dazzling and modern that looks out of this world. Taking something from horrible to amazing leaves a great sense of pride in our efforts.

Covacrete Resurfacing

The final overly satisfying part of our industry are happy clients. To firstly win the project, then give our clients our up most professionalism, along with getting all the process’s correct to complete the work properly and having our clients satisfied and happy with what we have done for them, this is the best sense of accomplishment we can ask for.

Next time you have a look over a great looking concrete project, have a little think to all the work and thought that has gone into creating such a project. You’ll find there was a concreter there at one stage looking back over the job with a big smile on their face feeling good about what they have achieved.

Little Things Feature

All The Little Things

Often spoken of lightly, the small items that are used during a concrete slab installation are often the most important. From Abel Flex to Control Joints and beyond, it is imperative they are installed correctly to ensure a quality installation.

Abel Flex Expansion Foam

Abel Flex is used at cold joints (new concrete against another hard compound). It is placed vertically and is used to allow the concrete to shrink during the setting and curing phase without leaving a gap between the two hard structures. It also allows the new concrete to slightly move away from the other hard structure again without leaving a gap later on in it’s life, plus, allows the new concrete to move closer to the other hard surface without causing too much friction and making the new concrete “lift” up the face of the opposing structure.

Abel Flex

Starter Dowels

Starter dowels are drilled into cold joint areas approximately 150mm into the adjoining hard surface. Then the new concrete is poured around the end sticking out. What this does is adhere the two hard surfaces together which stops the new concrete from either lifting or dropping as opposed to that other surface. This of course helps is strength overall, but also stop trip points from creating at that given area.

Concrete Dowels

Re-Entry Bars

Re-Entry bars are typically made from N12 deformed bar or R-11 3/bar trench mesh. They are placed at the internal corners of your new concrete installation which is a high percentage crack area. They act as an extra reinforcement attempting to stop the early cracking and control it from these points.

Re Entry Bar

Trimming Bars

Although not commonly used, trimming bars are installed around the perimeter of your new concrete slab attached to the slab mesh. They act for initial assistance in the setting tension of the concrete, which helps prevent and control cracking directly from the edges of the concrete.

N12 Deformed

Control Joints

Control joints can either be tooled into your concrete during the pouring phase, or can be saw cut into the surface after initial setting of the concrete. The length in between control joints is dictated by the thickness of the steel reinforcing that is being used, along with the installers general experience on where he/she predicts to be a high percentage crack point. They basically create a weaker spot in the concrete which is hoped that the concrete during tension will find it’s weaker spots to crack along, keeping said crack inside the control joint instead of being a dirty crack in the middle of nowhere.

Control Joints

There are also other minor things that are used during a concrete installation, but you’ll find these to be the most common and useful. When you receive your quotation, ask your contractor about these items. If they aren’t included in the pricing, then give us a call to quote your work and rest assured the installation is being done correctly.