QUESTION 2 You work as a material engineer with a consulting firm. Your client h
ID: 1712380 • Letter: Q
Question
QUESTION 2 You work as a material engineer with a consulting firm. Your client has appointed your firm to design a five-storied (concrete structure) beachside shopping complex at Location X. After site investigation, the results show that Location X is greatly polluted with sulphate and chloride ion. You are needed to write a report to your client, summarizing: (1) The site's conditions (5 marks); (2) Consequences to building structure if no precaution steps taken during concrete mixing (10 marks) (3) Suggest suitable concrete constituents for such construction. You are free to do any sketching or drawing for a better illustration (15 marks).Explanation / Answer
Since the construction is to be done on a beach side, the primary thing for an engineer is to see the effect of moisture of the reinforced concrete there. Moisture can prove to be extremely dangerous and corrosive for any foundartion and if the foundation of the structure falis, the entire structure fails.
Now the site investigation shows that the site has a lot of pollution of sulphate and chloride ions, this influences the electrical resistivity in the RCC and hence the kinetucs of the reinforcement corrosion. The beach side moisture will only add to the trouble of increasing the reinforcement corrosion, The sulphate ions can help slightly in reducing the corrosion but the dominating factor there is the moisture and the concentration of the chloride ions.
So, if the precautionary measures are not taken in making the concrete mix, the building is sure to fail in due course of time because the floundation will not stand the load of a 5 story building.
The remedies required for the concrete mix are listed as followes:
1) Good quality concrete should be used by adopting the rich mix, Efficient compaction during casting, Leak proof formwork, Adopting salt free sand, Using plasticizers, Using sulphate resisting cement and Pozzolana cement.
2) The cover used should be incresed
3) Galvanising could also be used.
4) Coating of the bars with paint, chemical compounds, metal epoxy coating etc.