Mapei · concrete repair

Mapei Planigrout 300

Mapei Planigrout 300 is a three-component, super-fluid, solvent-free epoxy resin grout for the high-precision anchoring of structural elements into concrete and for the structural infill of confined cavities where dimensional stability and high mechanical strength are required. The product is supplied as Part A (liquid epoxy resin), Part B (amine hardener) and Part C (graded silica filler aggregate) in pre-measured kits, mixed on site by paddle mixer to a self-levelling pourable consistency. Planigrout 300 develops compressive strength of approximately 100 MPa at 28 days, modulus of elasticity around 7 GPa, and is dimensionally stable (negligible cure shrinkage) under ambient conditions. TRSC specifies Planigrout 300 for the bedding of steel column base plates, for the precision anchoring of post-installed structural reinforcement where injection adhesives are inappropriate (typically large bar diameter or oversize hole-to-bar annulus), for machine baseplate grouting on industrial repair scopes, and for the structural infill of bearing pad seats and bridge bearing plinths. The product is poured rather than injected, which makes it the engineering choice over injection adhesives for cavities with horizontal or vertical pour access where the design intent is full-section infill rather than annular bond.

TRSC Specifier Commentary

Mapei Planigrout 300 occupies a specific specification slot in TRSC structural repair work: it is the high-strength, dimensionally-stable structural grout for poured infill applications where injection adhesives are not appropriate. The product is selected over Hilti HIT-RE 500 V4 injection epoxy on three job profiles: (1) large-diameter post-installed bar applications where the bar-to-hole annulus exceeds the injection adhesive's working range (typically over 8 mm annulus, or hole diameters exceeding 50 mm); (2) column base plate grouting on steel transfer columns where a 25-50 mm grout pad must transfer compression and shear from the column to the foundation; (3) bearing pad seat and bridge bearing plinth construction where the load transfer requires uniform contact and high compressive strength. The most common specification pitfalls TRSC encounters in the field are: (1) wrong grout selection — cementitious non-shrink grouts (typically 60 MPa class) are routinely substituted for Planigrout 300 by contractors looking to reduce material cost; the substitution fails on the dimensional-stability criterion and on the early-strength criterion when re-loading time is short; (2) inadequate venting — the pour cavity must include a vent path so the grout can displace air completely; trapped air pockets at the underside of column base plates are a common structural defect that is invisible until the column is later inspected; TRSC specifications require the contractor to detail vent locations and the pour sequence on the shop drawings; (3) cure-time confusion — Planigrout 300 reaches usable strength much faster than cementitious grout (50% of design strength at 24 hours at 23°C) but the contractor must hold the load off until full design strength is reached if the design called for full strength at re-loading; we specify a written re-load notification from the engineer rather than a calendar-based release. The product was used in the Q1 Tower Cyclone Albert Make Safe scope where the BMU davit base reinstatement required a high-strength, dimensionally-stable structural grout under tight programme constraints.

Frequently Asked Questions

Specification questions about Mapei Planigrout 300

When does TRSC specify Planigrout 300 over an injection epoxy adhesive?
Planigrout 300 is specified for poured infill applications where the cavity dimensions, the bar-to-hole annulus, or the design intent is full-section structural infill rather than annular bond. Typical job profiles are column base plate grouting, bearing pad seats, machine baseplate grouting, and large-diameter (>50 mm hole) post-installed rebar installations. Injection adhesives such as Hilti HIT-RE 500 V4 remain the choice for standard post-installed rebar where annular bond is the design mechanism.
Is Planigrout 300 dimensionally stable on cure?
Yes. The product is formulated to have negligible cure shrinkage and remains dimensionally stable under ambient conditions, which is why TRSC specifies it for column base plate grouting and bearing pad applications where shrinkage would create a structural defect. The product is supplied as a pre-blended three-component kit; substituting site-batched proportions or omitting the silica filler component compromises the dimensional-stability characteristic.
How is the pour vented to avoid trapped air pockets?
The pour cavity must include a vent path that allows displaced air to escape as the grout fills the cavity. For column base plate grouting, this typically means a vent hole at the highest point of the underside of the base plate. TRSC specifications require the contractor to detail vent locations and the pour sequence on the shop drawings as a witness hold point before the first column is grouted.
What standards govern Planigrout 300 specification?
In Australia, Planigrout 300 is specified under AS 3600-2018 for the structural design context (the grout is part of the load path and must develop the design compressive capacity) and EN 1504-6 (anchoring of reinforcement bars) where the product is used for post-installed reinforcement. TRSC remediation specifications cite both standards in the materials clause and require the contractor to retain Mapei batch numbers and conformity certificates as part of the project QA file.
Sources & Further Reading