11. Describe the properties and uses of concrete. (3 marks) 12. What is the role of admixtures in concrete? (3 marks) 13. Explain the different types of cement and their applications. (3 marks) 14. What are the properties of steel that make it suitable for construction? (3 marks) 15. Describe the process of curing in concrete construction. (3 marks) 16. What are the advantages and disadvantages of using timber in construction? (3 marks) 17. Explain the concept of high-performance concrete. (3 marks)