Sample text for tender: Concrete Waterproofing and Corrosion Protection

Invitation to Tender for Concrete Waterproofing and Corrosion Protection

Part 1 – General

1.01 Summary

A. This section specifies an inorganic, liquid additive based on complex alkali-silicates for waterproofing and corrosion protection of reinforced concrete, prestressed concrete, and accessories against chloride-induced corrosion.

B. Other sections of the specification referencing the works herein include, but are not limited to, the following:

  1. Section 03300 – Cast-in-Place Concrete
  2. Section 03365 – Prestressed Concrete
  3. Section 03400 – Precast Concrete

1.02 Requirements

A. Provide manufacturer’s product data, installation instructions, and material recommendations.

B. Require the following assurances and approvals for the inorganic, liquid additive based on complex alkali-silicates:

  1. Concrete modified with the additive shall be waterproof under hydrostatic pressure up to 7 bar when tested in accordance with CRC-C48 (Corps of Engineers Testing).
  2. Concrete modified with the additive shall reduce chloride ion penetration when tested in accordance with AASHTO T259 and T260.
  3. Concrete modified with the additive shall develop lower heat of hydration when tested in accordance with ASTM C186.
  4. Concrete modified with the additive shall reduce alkali-silica reaction when tested in accordance with ASTM C441.
  5. Concrete modified with the additive shall have reduced shrinkage when tested in accordance with ASTM C157.
  6. Concrete modified with the additive shall exhibit increased compressive strength (ASTM C39) and flexural strength (ASTM C78) compared to control concrete with the same slump and air content.
  7. Concrete modified with the additive shall demonstrate increased bond strength compared to control concrete with the same slump and air content, tested in accordance with ASTM C234.
  8. The manufacturer of the inorganic, liquid additive based on complex alkali-silicates must have a minimum of 20 years‘ experience in producing such products.

1.03 Quality Assurance

A. The concrete additive must be manufactured by a company with at least 20 years of experience in producing inorganic, liquid additives based on complex alkali-silicates for concrete. For products proposed but not specified in this tender, proof of capability to meet all specified requirements must be provided, along with a list of projects of similar construction completed more than 15 years ago.

B. A pre-construction meeting shall be held two weeks prior to the start of construction to review facilities and procedures for handling, installation, finishing, and curing of the additive-modified concrete specified.

C. A manufacturer’s representative shall be present at the beginning of the project during initial concrete placement. The engineer may waive the requirement for a manufacturer’s representative if the contractor demonstrates sufficient experience in the production and placement of the additive.

D. Trial mixes must be performed for all proposed mixtures to ensure that the concrete mixes meet all requirements specified in the tender.

Part 2 – Products

2.01 Manufacturing

A. Provide the specified inorganic, liquid additive based on complex alkali-silicates.

2.02 Concrete Mix

A. The additive shall be dosed at 1% by weight of cement (0.89L per 100kg of cement) (addition of pozzolan admixtures as necessary).

B. Concrete modified with the additive shall be mixed, delivered, and discharged batch by batch according to ASTM C94.

C. Concrete must achieve a minimum compressive strength of _______ N/mm² at 28 days unless otherwise specified on drawings or in specifications.

D. To determine freeze-thaw resistance, follow ACI 318 exposure for freeze-thaw durability. Concrete must have an air void content of ______ % +/- ______ %.

E. Concrete must have a maximum water-to-cementitious materials ratio (w/c) of ______.

F. Additional concrete admixtures approved per ASTM C494 Standard may be used if necessary.