Product Overview

Fosroc Conbextra GP1 is a single-component, pre-blended, cementitious non-shrink grout. Mixed with water on site, it produces a free-flowing, workable grout that can be poured or pumped into the gap between a structural steel base plate, precast element, or machinery skid and its concrete foundation. Conbextra GP1 achieves good compressive strength and, critically, is non-shrink in both the plastic and hardened states — eliminating the gaps and voids that form under base plates when ordinary cement or weak sand-cement grouts shrink on drying. It is the general-purpose grade in the Conbextra range, suitable for standard column base plates, anchor bolt pockets, and precast connections where loads are moderate and gaps are up to 50mm.

Typical Applications

• Column base plate grouting in steel-frame construction
• Anchor bolt and holding-down bolt pocket filling
• Precast concrete element joint grouting
• Machinery and equipment base grouting (non-vibrating)
• Bridge bearing grouting
• Void filling under precast slabs and beams
• Foundation bolt pocket sealing
• General gap filling in structural applications up to 50mm

Key Advantages

• Non-Shrink Performance: Conbextra GP1 is formulated with controlled expansion to compensate for shrinkage — the final hardened grout has zero net shrinkage, ensuring complete contact and load transfer across the grouted section
• Free-Flowing Consistency: At the correct water addition, GP1 flows freely to fill the entire void under base plates and into anchor bolt pockets — no need for vibration or tamping which could trap air
• High Compressive Strength: >30 MPa at 28 days provides adequate load-bearing capacity for standard base plate and bolt grouting. For higher loads and thicker gaps, the GP2 grade (>50 MPa) is recommended
• Simple Single-Component Mix: Just add water to the pre-weighed 25 kg bag — no cement, aggregate, or admixtures to proportion separately. Consistent quality every batch
• Chloride-Free: Safe for use around embedded steel and prestressed tendons without corrosion risk