Concrete

Concrete

During the previous week , I could able to work with laboratory operators and Quality Control engineer. There I could engage in concrete testing. In our project, if there would be any major concrete work, the lab should be informed before do the concrete work. Because those work should be done with required quality. Ready mixed concretes are used for all the structures. Therefore those concrete should be tested on site and as well as at the laboratory when do concreting. Basically there are two tests are done.

1. Slump test – done at site

2. Compaction test – done at the laboratory

Procedure of doing slump test

Slump test is more appropriate for testing the workability of concrete mix.

Method

1. Put concrete up to 1/3 of the slump corn

2. Compact by hand tamping

3. Continue the above two steps twice, until slump corn become full

4. After that clean around slump corn and level the top of the concrete mix.

5. Remove the slump corn carefully

6. Take the measurement of difference between top point of slump corn and top point of concrete sample.

Slump height should be within 125 – 175 mm.

in the test what we did at site was around 140mm and that was considered as ok. Also I found that the accuracy of this test is highly depend on the amount of mixing the concrete.

Compaction test.

Compaction tests for the concrete of our site is done at the peradeniya university lab. What we do only is preparation of concrete cubes for test. We used a 150x150x150 mm size concrete cubes for testing.

Machineries used for concreting in our site.

Pump car- used to place the concrete to required place.

Truck mixture – used to transport concrete from batching plant to the site.

Vibrator poker – to circulate and compact the concrete.