Observation

Few candidates were able to:

• state the function of cement, sand and crushed stones;
• describe the following curing methods: ponding and sprinkling.

However majority of the candidates failed to answer the questions.
The expected response to question 1 is as given below: 
1. (a)  function of each of the following constituents of concrete:
Cement   -         The cement paste covers the surface area of stone and sand particle in the mix and binds them together when the concrete hardens by hydration/acts as a binder.
Sand       -         To fill the voids or holes in the crushed stones and reduce its harshness.

• It reduces shrinkage; it fills the voids in the mix.
• It reduces shrinkage of cement in the mix.

Crushed stone - It gives strength to the mix.

(b)        description of the following curing methods used in concrete production
(i)         Ponding - keeping the concrete product in water.
-   keeping the concrete to be cured under water.
(ii)         Sprinkling: After the concrete is set continuous spraying with water is done to keep it damp.
(c)