First, I apologize for necro'ing a 6 year old thread.
I ran across mention of two additives to an Alker type mix that would extend the working time before it set up.
IIRC it was-
15% calcined gypsum (plaster of paris)
2.5% hydrated lime
1.66% Molasses (yes, apparently it's also used as an additive in portland cement based concretes as well)
0.833% Calcium Lignosulphonate (to Plaster of Paris dry wt)
Working time before it sets up is around 2 hours 15 minutes.
Should produce a brick that has about 620 psi on a crush test, or about double adobe.
I'm wondering about pouring walls with it using slip forms. If I make the height of the forms twice the height of a pour I should be able to leapfrog the form up the wall as the "bottom" pour has set up but while the "top" pour is still workable, thus preventing and "cold" joints. Or so I'm thinking....