Tests on Portland Cement (Lecture 5)

Question 1

Loss on Ignition (ASTM C114)

Answer 1

Purpose: To measure the level of pre-hydration of a cement
Test is reported in percentage of weight loss (assumed to represent moisture and CO2 in cement.
High loss % gives an indication of high prehydration and carbonation.

Question 2

What are the normal accepted values for Loss on Ignition test

Answer 2

3% for cement types I, II, III, V

2.5% for cement types IV

Question 3

Tests for fineness of cement

Answer 3

Purpose: to measure the fineness of a cement
fineness is characterized by specific surface (m^2/kg)
Blaine and Wagner Tests

Question 4

What are the ASTM C150 standards for Fineness?

Answer 4

160 m^2/kg for Wagner test
Minimum 280 ^2/kg for Blaine
these are for types I, II, IV, & V

Question 5

Wagner Turbidimeter Test (ASTM C115)

Answer 5

Fineness of cement is related to the rate of settlement of particles in the fluid (larger particles settle faster).
Cement sample is dispersed in kerosene, beam of light is passed through horizontally, photoelectric cell on other side is used to measure intensity of light passing through.
photocell reading a the specified times are used to measure specific surface.

Question 6

Blaine Permeability Test (ASTM C204)

Answer 6

Based on the principal that the rate of air flow in a sample is related to the pore size distribution which is related to particle size distribution.
Test results are reported in specific surface, using the measured time it takes for volume of air to flow through a column of a test specimen.

Question 7

Autoclave expansion of portland cement (ASTM C151)

Answer 7

Tests the ability for cement to retain its volume after settling. results are reported in % of length change. ASTM C150 limits expansion to .80%.

Question 8

Gilmore Needle Test (ASTM C266)

Answer 8

Tests the rate of setting. Test results are reported as initial and final setting times. Final set occurs when the pat can bear a needle without appreciable indentation.

Question 9

Vicar Needle Test (ASTM C191)

Answer 9

Tests the rate of setting. Test by determining the penetration of the Vicat needle in 30 seconds, every 15 mins. Initial setting time is when 25mm is reached in 30 seconds. Final setting time is when the needle doesn’t sink visibly into the paste.

Question 10

Compressive Strength Test (ASTM C109)

Answer 10

Purpose is to ensure the quality of cement with regards to strength development. Report compressive strength of force after 24hrs, 3 days, 7 days, and 28 days.
Required type 1- 1800 psi at 3 days
2800 psi at 7 days.

Question 11

Heat of Hydration of Hydraulic cement

Answer 11

Test measures heat of hydration at 7 and 28 days. Report the difference between the heat of the solution of a dry sample and that of a partially hydrated sample, which will give the heat of hydration.
Max of 60 cal/g at 7 days, 70 cal/g after 28 days for IV portland cement