Please find the attached files with the 7 days concrete cylinder compression test.
Deadlines: Task 1 – October 30th ; Task 2 – November 20th (Will not be extended) )
Task 1. Concrete mixing report: This must be submitted on October 30th. In this report, follow the report writing guidelines while highlighting the procedures undertaken for concrete materials batching, materials used, mix design used, slump test, poruring, consolidation of tamping, mixing, surface finishing and curing in a water bath and lesson learnt during mixing (include pictures where necessary).
1. Mix design: Write on effect of water cement ratio on concrete strength.
3. Batching: Write on why measuring correct proportions and accurate weighing of concrete ingredients important to the strength of a concrete
4. Mixing: State 3 – 4 reasons why machine mixing is appropriate compared to hand mixing for large projects. Also explain why a uniform appearance in concrete and mixing time is important.
5. transporting: State the effect of poor concrete transportation (delay) from mixing point to pouring to moulds on concrete strength
6. pouring (placing): State why drop height and horizontal movement during pouring is important.
7. vibrating (consolidating): State why it is important to tamp or vibrate or consolidate concrete before its initial set. What are the two basic methods of vibrating concrete
8. finishing: state why it is important to have a smooth or screeded concrete texture surface before curing.
9. curing: State why it important to maintain moisture and temperature in a freshly mixed concrete
Task 2. Concrete compression test report – This must be submitted on November 20th. In this report, follow the report writing guidelines (abstract or summary, objectives, introcution, tools/apparatus and methodology, result, conclusions) and write on the 7 day, 14 day, 21 day and 28 day test. Ensure you answer the post-lab questions below.
Post lab questions for task 2
1. Indicate the following in your report: Date of test, age of specimen, Curing conditions, including date of manufacture of specimen, and appearance of fractured faces of concrete and the type of fracture if they are unusual
2. Indicate in your report the size of specimen, area of specimen, the average characteristic compressive strength value (maximum point on stress-strain graph) for the two specimen concrete tested on 7 days. Do the same for 14 days, 21 days and 28 days.
3. Compare by plotting in excel the average compressive strength for the 7, 14, 21 and 28 days. State which of the days is highest and WHY e.g. The strength of concrete increases with age?
4. Compare the experimental modulus of elasticity to the theoretical expression by ASTM (Ec = 57000 sqrt(f’c), psi)