Chapter 2: Portland Cement (cont.)

Tests on Portland Cement Normally two types of cement tests are conducted as given below

• Field tests • Laboratory tests

B) Laboratory Tests Chemical Properties of Portland Cement T Chemical analysis

• Compound composition • Chemical limits

The relative quantities of each of these phases affects: • setting time • rate of strength development • overall strength • durability • color

Physical Properties of Portland Cement

• Fineness • Soundness • Consistency • Setting time • False set and flash set • Compressive strength • Heat of hydration • Loss on ignition • Density • Bulk density • Sulfate expansion

Fineness Fineness of cement is also important; it affects:

• rate of hydration • rate of setting • rate of hardening • durability (ASR) • rate of carbonation during storage • cost • rate of gypsum addition • bleeding

However, later strength is not directly affected.

Setting time tests

Initial setting time is the time from moment water is added until the paste ceases to be fluid and plastic.

Final setting time is the time from moment water is added for the paste to acquire a certain degree of hardness.

Soundness Test