2. MATERIALS FOR PERMACAST® TECHNOLOGY
This specification establishes the minimum standard for material and method of application for restoring and sealing leaking and deteriorated manholes by centrifugally casting a special mortar, onto its interior in one application at a specified thickness. The type of material, which may be selected, depends upon the source and concentration levels of the corrosive environment. See Table 3 for relative comparisons.
2.1 PERMACAST® MS-10,000
The material, PERMACAST® MS-10,000, is an ultra high strength, high build, corrosion resistant mortar, based on Portland cement fortified with micro silica. When mixed with the appropriate amount of water, a paste-like material will develop which may be sprayed, cast, pumped or gravity-flowed into any area ¼ inch and larger. This mortar will harden quickly without any need for special curing.
The hardened binder is dense and highly impermeable. The above performance is achieved by a complex formulation of mineral, organic and densifying agents and sophisticated chemical admixtures. Graded quartz sands are used to enhance particle packing and further improve the fluidity and hardened density. The composition also possesses excellent thin-section toughness, high modulus of elasticity and self-bonding. Fibers are added as an aid to casting, for increased cohesion and to enhance flexural strength.
The water content may be adjusted to achieve consistencies ranging from thin motor oil to modeling clay. Despite its high fluidity, the mortar has good wet adhesion and does not sag or run after placement. The mortar may be cast against soil, metals (including aluminum and lead), wood, plastic, cardboard or other normal construction material.
2.2 PERMACAST® CR-9,000
The material, PERMACAST® CR-9,000, shall be high strength, high build, corrosion resistant, resin impregnated synthetic mortar based on calcium aluminate cement and non-reactive quartz sand. When mixed with the appropriate amount of water, a paste-like material will develop which may be, sprayed, cast, pumped or gravity-flowed into any area 1/4 inch and larger.
This mortar will harden quickly without any need for special curing and can be considered mature after 24 hours. The hardened mortar has been purposely developed to be resistant to very aggressive soil conditions, such as low pH and high sulfates, seawater and dilute sulfuric acid resulting from
|bacteriological oxidation of hydrogen sulfide common to sanitary sewers. The raw materials are carefully selected and contain no calcium sulfates, no tri-calcium aluminates and no agents aggressive to reinforcing steel. The mortar is designed to resist biogenic corrosion in atmospheres in which Portland cements may reach levels as low as pH2. Like all calcium aluminate cements, it will experience the effects of corrosion at pH levels less than 2 but at much slower rates than Portland cement mortars.
The hardened binder is dense and relatively impermeable and does not contain any free lime hydrates. The above performance is achieved by a complex formulation of mineral, organic and densifying elements and sophisticated chemical admixtures. Finely ground silica quartz sands are used to enhance particle packing and further improve the fluidity and hardened density. The composition also possesses excellent thin-section toughness and bonding power. Non-metallic alkali resistant fibers control cracking and enhance its flexural resistance.
The mortar can be used as the sole protection against aggressive elements common to most sanitary sewer systems. The water content may be reduced to achieve any consistency ranging from thin motor oil to that of modeling clay. Despite its high fluidity, the mortar has good wet adhesion and does not sag or run after placement. The mortar may be cast against soil, metals (including aluminum and lead), wood, plastic, cardboard or any other normal construction material.
2.3 COR+GARD® COMPOSITE
COR+GARD® is a two-component 100% solids epoxy especially formulated for use in sewer systems. It is white in color for enhanced visibility. It is usually applied robotically from the PERMACAST® patented applicator for uniform distribution over the entire interior surface of manholes, pipe, and similar structures without requiring entry. It will cure quickly, even when immersed in fresh or salt waters. It rapidly forms a tenacious bond to freshly applied PERMACAST® mortars, which are formulated to prevent delaminating calcium powders during hydration. COR+GARD® composite produces a smooth, glossy and homogenous protective layer that is impervious to biological corrosion, water, oils and most chemicals.
Once the cementitious underlayment has been applied to seal, reinforce and smooth the existing interior surface, the COR+GARD® epoxy shall be applied to a minimum thickness of .065 inches to provide a complete and uniform vapor barrier against attack by sewer gases and corrosion causing bacteria. The surface shall be free of entrapped air bubbles or holidays.