Two Grout Families, Different Strengths
Structural grouting — filling gaps between machine bases and foundations, anchoring equipment, or consolidating concrete — requires materials that flow into confined spaces, develop high compressive strength, and maintain volume stability without shrinking.
Two product families dominate: cementitious non-shrink grout (modified Portland cement systems) and epoxy grout (100% resin systems). The choice between them depends on the application requirements, environmental conditions, and budget.
Cementitious Non-Shrink Grout
Our cementitious grout range includes standard high-strength (XQ-GJ-C60), fast-setting (XQ-GJ-FS), ultra-fine (XQ-GJ-UF), and underwater (XQ-GJ-UW) formulations.
Key properties (XQ-GJ-C60):- Compressive strength at 28 days: ≥ 60 MPa
- Expansion: 0.02-0.05% (compensated shrinkage)
- Flow spread: ≥ 300mm
- Maximum aggregate size: 2mm
- Temperature range: 5-35°C application
Epoxy Grout
Our epoxy grout (XQ-GJ-E) is a three-component system (resin, hardener, and aggregate filler) that provides the highest performance for demanding applications.
Key properties:- Compressive strength: ≥ 80 MPa
- Tensile strength: ≥ 15 MPa
- Bond strength to steel: ≥ 20 MPa
- Chemical resistance: Excellent (acids, alkalis, oils, solvents)
- Shrinkage: Zero (slight expansion during cure)
- Temperature range: 10-35°C application
Selection Decision Matrix
| Factor | Cementitious | Epoxy |
|---|---|---|
| Compressive strength needed | ≤ 60 MPa | > 60 MPa |
| Chemical exposure | None/mild | Aggressive |
| Dynamic load / vibration | Low | High |
| Operating temperature range | Normal | Wide range needed |
| Budget constraint | Tight | Flexible |
| Gap thickness | 10-200mm | 25-150mm |
| Cure conditions | Can moist cure | Cannot moist cure |
Specialized Grout Applications
Underwater Grouting (XQ-GJ-UW)
Our underwater cementitious grout is designed to displace water and set in fully submerged conditions. Anti-washout additives prevent cement particles from being carried away by water currents. Applications include dam repairs, bridge pile caps, marine foundations, and water treatment structures.Ultra-Fine Injection Grouting (XQ-GJ-UF)
Micro-cement grout with particle size below 20 μm for injection into fine cracks, voids, and soil. Penetrates pore spaces that standard grout cannot reach. Used for foundation consolidation, rock mass stabilization, and tunnel pre-injection.Fast-Setting Grout (XQ-GJ-FS)
Modified cementitious grout reaching 20 MPa compressive strength within 4 hours. Designed for emergency repairs and situations where rapid return to service is required. Ideal for bridge bearing replacement, rail infrastructure, and industrial equipment realignment.Application Best Practices
Gap preparation: Clean all surfaces of oil, grease, dust, and loose material. Concrete surfaces should be saturated surface-dry. Steel surfaces should be clean and free of mill scale in the contact zone. Formwork: Build leak-proof formwork with a minimum 25mm head above the highest point to be grouted. Include a pouring funnel or reservoir to maintain positive head pressure throughout the pour. Mixing: Follow the exact water-to-powder ratio specified on the datasheet. Over-watering is the most common mistake with cementitious grout — it increases flowability but destroys strength and causes shrinkage. Pouring: Pour from one side only and allow grout to flow across the base to the opposite side. This prevents air entrapment. Do not vibrate epoxy grout — vibration can cause aggregate separation.Frequently Asked Questions
What is the difference between cementitious grout and epoxy grout?
Cementitious grout is a Portland cement-based material modified with expansive agents to prevent shrinkage. It costs $15 to $30 per 25 kg bag and achieves 40 to 80 MPa compressive strength. Epoxy grout is a 100 percent resin system with no cement — it costs $80 to $150 per unit and achieves 60 to 100 MPa with superior chemical resistance. Use cementitious grout for standard machine bases, anchor bolt grouting, and column jacketing. Use epoxy grout when chemical exposure, vibration loading, or ultra-high precision alignment demands the extra performance.
Can cementitious grout be used for machinery foundations?
Yes, cementitious non-shrink grout is the standard material for machinery base grouting in most industrial applications. Our high-strength cementitious grout XQ-GJ-C60 achieves 60 MPa compressive strength and is suitable for pumps, compressors, generators, and most rotating equipment. Epoxy grout is only necessary for equipment subject to chemical spills (acid, alkali, solvents), extreme vibration, or requiring alignment tolerance under 0.05 mm.
What is structural grout used for?
Structural grout fills load-bearing gaps where the grout must carry and distribute compressive loads — including machine base plates to foundations, bridge bearing pads, precast element connections, column jackets for seismic retrofit, and post-tensioning duct filling. Unlike non-structural grout (used for tile joints or cosmetic filling), structural grout must provide controlled expansion, zero shrinkage after hardening, and compressive strength matching or exceeding the surrounding concrete.
How do you prevent cementitious grout from shrinking?
Quality cementitious grout prevents shrinkage through three mechanisms: (1) expansive agents (calcium oxide or calcium sulfoaluminate) that generate controlled expansion during the plastic phase; (2) gas-generating admixtures that create micro-expansion bubbles; (3) polymer modification that reduces drying shrinkage. Proper placement technique is also critical — pour from one side only to eliminate air pockets, do not add excess water, and cure with wet burlap or curing compound for at least 24 hours.
Related Guides
- Non-Shrink Cementitious Grout: Types, ASTM Data & Equipment Base Selection — Deep dive into ASTM C1107 graded cementitious grouts.
- Cementitious Grout Types, Strength & Applications — Comprehensive coverage of all cementitious grout formulations.
- Epoxy Grout for Machinery Foundations & Baseplate Grouting — When to use epoxy grout for heavy rotating equipment.
- Concrete Foundation Repair Methods & Materials — Resin injection, grouting, and CFRP for foundation rehabilitation.
- Two-Part Structural Epoxy Guide — The epoxy chemistry behind both grout and structural adhesive systems.