Under Queensland’s Transport and Main Roads Specifications (TMR) MRTS16 for Landscape and Revegetation Works, agricultural gypsum used as a soil amelioration agent must meet a Gypsum purity (% CaSO₄⋅2H₂O) of 80 or above and be submitted for laboratory compliance testing using MRTS16 Form C / Form I documentation.
Other General Gypsum Quality Criteria for the TMR Road Projects:
have sodium content < 0.8%
have sodium chloride content < 2%
have a total content (x-ray fluorescence test) of:
i. 20% calcium (Ca)
ii. 15% sulphur (S), and
iii. < 2% sodium chloride (NaCl).
if manufactured – have a total content of heavy metals:
i. < 0.001% cadmium (Cd), and
ii. < 0.01% lead (Pb).
have a particle size distribution of:
i. 100% by weight to pass a 6 mm sieve
ii. 80% by weight to pass a 4 mm sieve, and
iii. 50% by weight to pass a 2 mm sieve.
