Choosing Base-Plate Grout

Quick pick (TL;DR)

Static column/structure bases → cementitious non-shrink grout (ASTM C1107).
Rotating/vibrating machinery, dynamic or chemical exposure → epoxy grout (higher strength, no shrinkage, vibration- & chemical-resistant) per API 686, with ≥ 90% effective bearing.
Always non-shrink; pour with a head box; cure properly.

Step 1 — Cementitious vs epoxy

	Cementitious	Epoxy
Use for	Static bases	Machinery / dynamic / chemical
Strength	~ 50–60 MPa	~ 80–120 MPa
Vibration	Moderate	Excellent
Chemical	Limited	High
Cost	Low	Higher

Step 2 — Bearing check

Grout bearing

Given Vertical load = 500 kN Base plate = 600 × 400 mm Step 1 — Bearing pressure A = 600 × 400 = 240,000 mm² f_b = 500,000 / 240,000 = 2.08 MPa Step 2 — Compare epoxy grout ≥ 80 MPa ≫ 2.08 MPa → OK So why epoxy? strength is not the issue — chosen for vibration, no shrinkage, ≥90% contact (API 686)

Strength rarely governs — choose epoxy for dynamics, zero shrinkage and full bearing.

Step 3 — Application essentials

Always non-shrink — gaps cause point loading.
Machinery: ≥ 90% bearing; pour with head box.
Prep concrete; soak/prime; cure properly.
Extend thick epoxy pours to control exotherm.

Grout bearing calculator

Bearing pressure vs grout strength

f_b = load/area — strength rarely governs; choose by service.

Load (kN)

Plate B (mm)

Plate L (mm)

Grout strength (MPa)

Epoxy for dynamic machinery (API 686); cementitious for static bases.

Common mistakes

Cementitious under vibrating machinery.
Voids → uneven bearing.
Plain mortar instead of non-shrink grout.

Requisition & datasheet

Application, load, service, grout type.
Thickness, bearing target, method, standard.

Frequently asked questions

What should I know about Choosing Base-Plate Grout?

Static column/structure bases → cementitious non-shrink grout (ASTM C1107). Rotating/vibrating machinery, dynamic or chemical exposure → epoxy grout (higher strength, no shrinkage, vibration- & chemical-resistant) per API 686, with ≥ 90% effective bearing. Always non-shrink; pour with a head box; cure properly.

Which standards or codes apply?

ASTM C1107 (cementitious non-shrink grout), API 686 (machinery grouting), manufacturer data for epoxy grouts.

Standards — ASTM C1107; API 686; manufacturer data.