The twin 84" CMP in a neighborhood in Matthews, NC were causing trouble to the citizens and to the town. The road was cracking above the pipes, and the city had been patched the cracking a few times, only to see the patches crack. They were unaware that pipes in this condition could be restored in situ without digging and replacing before they met us. We were able to build them two new pipes rated to last 123 years at a much lower cost than dig and replace or CIPP, and we did it all in 2 and a half days, without ever stopping traffic.
The Town of Matthews had been experiencing cracking in the road above these pipes, and was caught in a continuous cycle of patching and cracking.
Cracking in the asphalt and patches the road due to the existence of the substandard 84" CMPs below.
Cracking in asphalt and patch in road. The Town had to patch the cracks continuously because the pipes below were allowing infiltration and erosion of fill around the pipes.
The invert in the main pipe was almost completely gone - all that remained was the few bands of metal depicted here.
There was barely anything left of the invert in the main pipe when we arrived.
This depicts the lack of invert in the 84" CMP below.
Ricardo is pumping the water out of the hole that has been created where the invert once existed, so we can solve the problem.
Almost nonexistent invert in main pipe.
Rotted invert on overflow pipe, which exists at higher elevation than the main pipe.
Gap between CMP and poured-in-place outfall structure created by curing shrinkage.
Hydroactive grout has begun to push up from under the pipe and through the gap created by curing shrinkage of the headwall structure.
We have pumped hydroactive grout behind the pipe here. We have filled the void, and the material began to push up through the separated joint, permanently sealing it.
This is a joint that has been sealed with hydroactive grout. To the left of the now sealed joint, there is an injection port. We injected material into that port until the void was full and the material forced its way through the separated joint. The void created by the separated joint is responsible for some of the cracking in the road above.
The Town had poured an invert in part of the over flow pipe with flowable fill. Because that material shrinks as it cures, there was a gap between the concrete and the metal pipe. That gap was allowing infiltration and creating voids around the pipe. We filled the voids and sealed the gap.
We injected through the injection ports on either side of the joint. The material filled the void created by the existence of the separated joint, sealed the joint, and sealed the gap between the flowable fill and the CMP.
Sealed joint and sealed gap between flowable fill Town poured as invert which shrunk away from CMP during cure.
This is a joint the Town had attempted to seal with cementitious grout. This is not a fix, as is clear here. Grout moves during cure, and therefore, cannot bond to the existing structure. Thus, infiltration and exfiltration can still occur. Now, it is sealed with hydroactive grout, and the void it created has been filled.
Here, the cementitous grout the Town had attempted to use to seal the joint has not worked. We have filled the voids and sealed the joint with hydroactive grout, where the cementitious grout did not create a bond.
Spincasting in action.
Miguel is spincasting pipe repair mortar to engineered thickness.
Miguel running the spincaster, centrifugally casting Centri-Cast Pipe Repair Mortar to engineered thickness to build a new pipe.
Spincasted new 84" pipe.
Spincasted new 84" pipe