Fosroc Conbextra BB80

Fosroc Conbextra BB80 | Non-shrink cementitious bearing grout for use at a wide variety of applications

Conbextra BB80 is a specialized high-strength grout formulated for various heavy-duty applications such as grouting beneath bridge bearings, parapet posts, flanged lighting columns, heavy stanchion bases, and base plates for reciprocating machines. Here are the key details about its uses, properties, and application instructions:

Uses

• Grouting beneath bridge bearings, parapet posts, flanged lighting columns, heavy stanchion bases, and base plates for reciprocating machines.
• Offers non-shrink properties, high early and ultimate compressive strengths, good flow (especially at low temperatures), and low permeability ensuring durability.
• Suitable for pouring or pumping.

Standards Compliance

• Formulated to comply with ASTM C1107 Grade C.

Description

• Supplied as a ready-to-use dry powder in 25kg plastic bags.
• Specifically designed for grouting in various heavy-duty applications.
• Upon adding controlled clean water, it forms a free-flowing grout with high early and ultimate strengths suitable for section thicknesses ranging from 10mm to 100mm. For thicker sections, clean washed 5-10mm aggregate can be incorporated at a ratio not exceeding 1:1.

Specification

• Specifies the water:powder ratio at 0.15 and desired compressive strength at different durations.

Properties

• Compressive Strength: Ranges from 45 N/mm2 @ 24 hours to 85 N/mm2 @ 28 days depending on testing duration.
• Expansion: Controlled positive expansion.
• Total Chloride Ion Content: < 0.1%.
• Low chloride permeability and water permeability.

Instructions for Use

Preparation

• Ensure concrete surfaces are clean and free from oil, grease, or loose material.
• Pre-soak the cleaned substrate with fresh water for a minimum of 2 hours before grouting.

Placing

• Place the grout within 15 minutes of mixing for optimal expansion.
• Suitable for thicknesses up to 100mm in a single pour. For thicker sections, aggregate can be incorporated but should not exceed a 1:1 ratio with the grout.

Curing and Cleaning

• Thoroughly cure exposed areas using curing membranes or continuous application of water and/or wet hessian.
• Clean tools and equipment immediately after use with clean water.

Sampling Procedure

• Special sampling procedures are required; contact Fosroc office for further details.

Mixing

• Use a mechanically powered grout mixer for best results. A specific water-to-powder ratio is given to produce a fluid grout.
• Mix continuously for 5 minutes on high shear/speed to achieve a smooth, even consistency.

Formwork and Levelling

• Formwork should be leakproof. The gap width between perimeter formwork and plate edge should not exceed 75mm on the pouring side and 25mm on the opposite side.
• Use sacrificial semi-dry sand and cement formwork or foam rubber strip/mastic sealant to achieve leakproof construction.

Notes

• For the first few minutes of mixing, the mixture will be of a stiff consistency, gradually becoming fluid.