How to Test for Concrete Slump
A concrete slump test is a method of measuring the consistency of fresh concrete. It’s a simple and easy way to check the workability of multiple batches before they set.
Wright Minimix are industry-leading concrete specialists, supplying ready-mix concrete and liquid screed across the South West. In this post, we explain what a slump test is, why it’s necessary, and how to carry one out.
What is a concrete slump test?
A concrete slump test is a routine procedure for seeing how easily a batch of concrete will flow. It’s low cost, easy to carry out, and produces immediate results.
Why perform a concrete slump test?
Before laying concrete, it’s important to check all batches have the same consistency. This ensures a constant quality and strength throughout. A slump test reveals the water-cement ratio, letting you know whether more or less cement needs to be added to the mix.
Too much water will weaken a mix. If you require a higher workability, you must raise the amount of cement within the mix.
What is the method for carrying out a concrete slump test?
To carry out a concrete slump test, you’ll need a slump cone, a measuring stick, a steel rod, and - of course - the concrete itself. Follow the steps below to find out the slump result of your concrete:
- Place the slump cone on a flat surface and stand on the footholds either side.
- Pour a layer of concrete into the cone, and use the steel rod in a circular fashion to smooth and compact it around 25 times. Make sure to penetrate the previous layer by about an inch. Repeat this with another layer of concrete on top.
- Pour in one final layer and rod it 25 times. The rod should penetrate the second layer, but not go through it fully. If the concrete is compacted beneath the top of the mould, stop rodding and add more concrete, then continue.
- After pouring the layers, clear away any overflow from the top and base of the cone. Double check the concrete reaches the top level of the cone.
- Slowly lift the cone up, shaking it gently until it is free of the concrete. Place the cone upside down next to the concrete, which will soon start to slump.
- Lay the steel rod across the top of the upturned cone so it hangs over the concrete.
- Measure the distance from the rod to the top of the slump. The level of slump is measured to the nearest 1/4 of an inch. The recorded results are the slump of the concrete.
Talk to the South’s concrete specialists
Wright Minimix have been delivering premium concrete solutions for over two decades. Whether you’re in need of ready-mix concrete, concrete blocks, or a heavy-duty concrete pump, we’ll be there to provide it on time and on budget.