Patent ID: 8308470

Claim:
A cementitious material delivery system comprising: a flow divider configured to divide a flow of cementitious material into a first stream and a second stream that is separate from the first stream; a first chemical agent which cures the cementitious material at a first rate when mixed with the cementitious material; a first mixer configured to mix the first chemical agent with the first stream of cementitious material to produce a first mixed stream of cementitious material; a second chemical agent which cures the cementitious material at a second rate when mixed with the cementitious material which is faster than the first rate; a second mixer separate from the first mixer and configured to mix the second chemical agent with the second stream of cementitious material to produce a second mixed stream of cementitious material; and a nozzle configured to extrude the first mixed stream of cementitious material and the second mixed stream of cementitious material separate from the first mixed stream of cementitious material.