Question

The shape and surface texture of aggregate particles are important for both portland cement concrete and asphalt concrete. For preparing PCC, would you prefer round and smooth aggregate or rough and angular aggregate? Briefly explain why (no more than two lines). For preparing HMA, would you prefer round and smooth aggregate or rough and angular aggregate? Briefly explain why (no more than two lines).

Answer 1

Answer:

• For preparing PCC we would prefer smooth and round aggregate

• For preparing HMA we would prefer rough and angular aggregate

Explanation:

• For preparing PCC (plain cement concrete), a smooth and round aggregate is preferable to increase the workability of fresh concrete during mixing. The cementing action and aggregate interlock are responsible for the stability of PCC.

• For preparing HMA (hot mix asphalt) rough and angular aggregate is preferred because the aggregate interlock develops the stability of asphalt.