Monday, August 29, 2011

The making of a specimen

I spend most of my time in the laboratory to destroy slabs - but before doing so, we first have to make our specimens.
The slabs I'm testing are reinforced concrete slabs, which are cast in timber formwork in the laboratory hall. The reinforcement is delivered as ready-made cages according to our drawings, and the concrete is delivered by a truck mixer from a nearby plant.

We start with the timber formwork:

And we also have the reinforcement in our laboratory hall:

One of these cages is used per slab:

Then, the reinforcement is placed into the formwork:

Now we're ready to pour on some concrete... Notice the mixer truck at the entrance of the laboratory.

The concrete is taken to the formwork and then poured into it:

Meanwhile, we also cast small cubes to check the material properties of the concrete:

After pouring the concrete, the surface of the slab needs to be finished:

The result: some freshly-made concrete slabs:

These can be used in our setup after typically 28 days - ready to suffer!


  1. your post is good. . let me tell u one thing that Blogs have become latest and important source of quality free information

  2. I remember the biggest issue i faced was spending so much time in designing mix for 6000 Psi strength. (our advisor is a wise man, we asked for ready mixed concrete, he simply said NO, propose a mix design, you will learn a lot) Later it came out that the aggregate (from Margalla quarry) started crushing at 5500psi. So there was no other way than encorporating mix design of 5500psi.

    So somewhere somehow somethings were a lot challenging than the ACTUAL CASTING AND TESTING work, But that 1.5 month period taught a hell out of concrete materials (playing with w/c ratio, workability, strength).

  3. That's interesting - I have never worked on designing a mix myself, but hopefully I'll get a chance at this in the future.