REPORT

DATE: 11 MAY 2012

SUBJECT: BQES 1202- CONSTRUCTION TECHNOLOGY II

LECTURER: PUAN NORHANIM ZAKARIA

ACTIVITY; SLUMP TEST & CUBE TEST

GROUP 1

MEMBERS;

1) AMIRUL RASYID BIN SHANSUL BAHRI BEQ 110003

2) FATIN KHAIRUNNISA BT MOHD NASIR BEQ 110011

3) HARUN AL RASHID BIN MUHANI BEQ 110015

4) MOHD HAFIZ BIN MOHD SAPIEE BEQ 110023

5) MUHAMMAD AZRUL HAZMAN BIN HAMDAN BEQ 110024

6) NAZIHAH BT YUSOP BEQ 110026

7) SHAHRIN BIN MOHAMAD BEQ 110037

8) MOHD RIJALUDDIN RABBANI MOHD NASIR BEQ 110047

9) MUHAMAD AKMAL

10) AMIN ALI DOSTI

OBJECTIVE: To determine the strength and workability of concrete mixture

THEORY: To determine the concrete fulfils the required specification, 2 types of concrete testing to be conducted are slump test and cube test (compression test).

Slump testThis is a site test to determine the workability of the ready mixed concrete just before its placing to final position inside the formwork, and is always conducted by the supervisor on site. However in mid of concreting process , should the site supervisor visually finds that the green concrete becomes dry or the placement of concrete has been interrupted , a re-test on the remaining concrete should be conducted in particular of the pour for congested reinforcement area

APPARATUS

Compression testThe Compression Test is a laboratory test to determine the characteristic strength of the concrete but the making of test cubes is sometimes carried out by the supervisor on site. This cube test result is very important to the acceptance of insitu concrete work since it demonstrates the strength of the design mix.

APPARATUS

SLUMP TEST REPORT

Relevant Standards: BS 1881: Part 125: 1983. Testing concrete- Methods for mixing and sampling fresh concrete in the laboratory.

Step 1: Sample Preparation

1. The quantity of concrete produced was 10% more than required for the proposed tests.2. The aggregates were in laboratory dry condition. Adjustment was made to the concrete mix

proportion to allow for adsorption of mix water by aggregates.

Step 2: Mixing

1. The pan and paddles were lightly moisturized.2. Those material were added in order;

a. Coarse aggregateb. Fine aggregatec. Sand

3. The materials were mixed for 30 seconds.

4. Half of mix water was added and mix continuing for 1 minute.5. The material was mixed thoroughly by hand.6. The mixture was left covered for 8 minutes to allowed water absorption by aggregates.7. The cement was spread evenly over the aggregates and continued mixed for 1 minute.

8. The paddles were cleaned and material was mixed thoroughly by hand.9. The remaining water was added and the material was mixed for further 2 minutes.10. For ensuring homogeneity, the material was mixed by hand.

Step 3: Testing.

1. The following tests were carried out, in order; Workability Plastic Density

2. For the first slump test. Our group got collapse slump.

3. The test was repeated, return used concrete to the mixer and re-mix for 30 seconds.

4. For the second slump test. Our group got shear slump.5. The test was repeated again, return used concrete to the mixer and re-mix for 30 seconds.6. For the third slump test, our group successfully got true slump with 7-10 mm slump.

SLUMP TEST REPORT

1. 150 mm standard cube mold is to be used for concrete mix and 100 mm standard cube mold is to be used for grout mix.

2. Make sure the apparatus and associated equipment are clean before test and free from hardened concrete and superfluous water .

3. Assemble the cube mold correctly and ensure all nuts are tightened.

4. Apply a light coat of proprietary mold oil on the internal faces of the mold.

5. Place the mold on level firm ground and fill with sampled concrete to a layer of about 50 mm thick.

6. Compact the layer of concrete thoroughly by tamping the whole surface area with the Standard Tamping Bar. (Note that no less than 35 tamps / layer for 150 mm mold and no less than 25 tamps / layer for 100 mm mold).

7. Repeat Steps 5 & 6 until the mold is all filled. (Note that 3 layers to be proceeded for 150 mm mold and 2 layers for 100 mm mold).

8. Remove the surplus concrete after the mold is fully filled and trowel the top surface flush with the mold.

9. Mark the cube surface with an identification number (say simply 1, 2, 3, etc) with a nail or match stick and record these numbers in respect with the concrete truck and location of pour where the sampled concrete is obtained.

10. Cover the cube surface with a piece of damp cloth or polythene sheeting and keep the cube in a place free from vibration for about 24 hours to allow initial set .

11. Strip off the mold pieces in about 24 hours after the respective pour is cast. Press the concrete surface with the thumb to see any denting to ensure the concrete is sufficiently hardened, or otherwise de-molding has to be delayed for one more day

TO CORRECT THE MIXTURE

If the slump is not within the desired range, or the mixture is obviously either too fluid or too stiff, the proportions of the mixture must be change. To make more fluid and increase the slump, increase the proportion of water and cement without changing the water/cement ratio. To make the mixture stiffer and decrease the slump, increase the proportion of aggregates without changing the fine/course aggregate ratio. Do not just add water to make the mix more fluid; this will weaken the concrete.