What ratios can be suggested for ternary blending of cement with PFA and GGBS. Taking into account that the cement will be of Cem I quality and we would like to achieve a 32.5MPa product.
admin
The ratios for blending GGBS or fly ash to achieve a 32.5 MPa product will depend on the hydraulic activity of the individual components. The only way to define these ratios is going to be by the process of producing trial mixes and physical testing of concrete made from the mixes. It may be possible to add up to 65 per cent GGBS as this material is both cementitious and pozzolanic. The limit of PFA addition will be much lower, perhaps around 25 per cent, as this is only pozzolanic.
admin
What is the difference between type 1 cement and type 3 cement? Our ready- mixers are trying to come up with a mix that we can strike with a straight edge and make it look nice but get up to 3500 psi in 4 hours Right now we are using a stone mix with 8 1/3 sack and 7.5 per cent NCA.
admin
Essentially Type 3 is a finer ground version of Type 1 cement and would normally be made from the same clinker source as Type 1. For Type 3 cement there are minimum strength specifications in the ASTM standard C150 for 1 day strength (none are set for Type 1) and at 3 days the strength minimum specified is twice that set for Type 1 cement.
The concrete strength requirement of 3500 psi at 4 hours is quite demanding and would need careful control of the concrete mix with accelerating additives/high range water reducers which do not retard the mix.