The Aqueduct Water Supply System was built in the early 1900's and suffered from water leaks and penetration of natural crude oil from overlying geological deposits through the concrete of walls and ceilings.
The companies "Kalmatron® Corporation", "Shotcrete Technologies Inc.", and "Howell Enterprises Inc." provide unique shotcrete technologies and materials for restoration of concrete liquid impermeability, superficial density and compressive strength.
The application was provided by the staff of the "Department of Water & Power City of Los Angeles." The necessity to repair both external and internal sides of the aqueduct created two different shotcrete mix designs and technologies of application.
The simplicity and efficiency of the equipment and the admixture to the shotcrete mix KALMATRON® KF-A allowed to stop leakages of water and oil without preliminary crack patching jobs, plugging of leaking holes, placing drainage pipes, et. With limited time per shift, it greatly economized labor expenses and construction time.
Highest performance of successfully combined inventions classifies it as the SHIELDCRETE Remedial Layer.
Massive damage to concrete during almost 10 decades caused leakages of underground water and crude oil through the concrete from overlying geological deposits.
INTERNAL APPLICATION OF SHIELDCRETE
The mix design is simple - a rationed blend of sand, cement, KALMATRON® KF-A and water. Slump of the batch at 3 1/2" allowed to avoid sliding of fresh shotcrete from the soaked vertical surfaces and for stopping persistent leaks with highest performance of application.
The creamy effect seen in the SHIELDCRETE mix, with a water to cement ratio below 0.42 achieved with KALMATRON® KF-A application as 17 Lbs/cu. yd.
Slump measured after KALMATRON® KF-A premix is 2.56" with pumpability up to 500 feet of hose length.
The temperature of the air is higher at 8.5ºF than of the SHIELDCRETE mix in the hopper, resulting in an oxidation-decay process of cement by KALMATRON® KF-A that reduces exothermic heat by 25% to 50%.
Shotcreting has been done with a minimum of rebound, immediate adhesion, and one pass 1/2" to 3/4" thick application. This is another advantage of the "Creamy effect" achieved by KALMATRON® KF-A
12 hours after SHIELDCRETE application oil leaks from ceilings and walls have demigrated to the floor. The high density of the SHIELDCRETE matrix isolates any leaks between the original concrete surface and the new SHIELDCRETE layer.
Internal view of the aqueduct 24 hours after SHIELDCRETE application.
A patch of KALMATRON® KF-C stops an oil leak on the ceiling in a one step application.
Fragment of an aqueduct wall 24 hours after SHIELDCRETE application.
EXTERNAL APPLICATION OF SHIELDCRETE
Most external damage to aqueducts occurs as the structure's concrete ages and gradually deteriorates under cycling temperatures. In accordance with the project, the external concrete of an aqueduct is renovated through reinforcment with structured rebar and massive application of SHIELDCRETE.
The concrete of the excavated area was reinforced by structured rebar. Shown above is the Robotic Arm engineered by "Shotcrete Technologies Inc." for maximum productivity and consistence of SHIELDCRETE application.
Reinforcing the external structure before SHIELDCRETE application. Structured rebar forms a reliable shielding coat that improves the durability of the aqueduct.
The Robotic Arm used for SHIELDCRETE application provides a wide range of thickness from 1/4" to 1 foot with consistent homogeneity of applied layers. The Robotic Arm makes application possible from uppermost point of the structure to the ground line by one operator.
KALMATRON® Corporation
Research & Production Department
236 West Portal Av., MBP 153, San Francisco, CA 94127
Internal view of the aqueduct 12 months after SHIELDCRETE application. The oil leaks from ceilings and walls have demigrated to the floor. The currents of water have colored the surface of the walls with brawny patterns by natural organic contaminations. Despite the hydraulic pressure of the entering waterfall, which is over 50 Bar, not one indication of damage was observed.
12 hours after SHIELDCRETE application oil leaks from ceilings and walls have demigrated to the floor. The high density of the SHIELDCRETE matrix isolates any leaks between the original concrete surface and the new SHIELDCRETE layer.
The Aqueduct Water Supply System was built in the early 1900's and suffered from water leaks and penetration of natural crude oil from overlying geological deposits through the concrete of walls and ceilings.
