UHPC Floor Repair Technical Manual: Rapid Repair Solutions for Existing Industrial Floors

UHPC Floor Repair Technical Manual: Rapid Repair Solutions for Existing Industrial Floors

1. The Underestimated Need for Floor Repair

China's industrial building stock is vast, with many factories, warehouses, and logistics parks built 10-30 years ago experiencing varying degrees of floor deterioration. Owners face a common dilemma: floors need repair, but traditional methods—demolishing and replacing—are costly and cause extended downtime, often unacceptable for continuous operations.

The Taiheng UHPC long-lasting repair product line offers a systematic solution: overlay the distressed area with a UHPC repair layer without removing the existing floor, quickly restoring functionality and extending service life.

---

2. Common Floor Distress Types and Causes

Accurate diagnosis of distress type and cause is essential for selecting the appropriate repair strategy.

Cracking (most common)

• Shrinkage cracks: occur during concrete curing, typically fine and evenly distributed.
• Load-induced cracks: caused by overloading or fatigue, often near concentrated load points, with wider openings.

Repair strategy: Fine cracks (<0.2 mm) are sealed by grouting; wider cracks are widened, cleaned, grouted, and then covered with a UHPC overlay.

Dusting
Caused by high water-cement ratio, inadequate curing, or poor bond between surface and base. Dusting floors generate fine powder under forklift traffic, contaminating the environment and accelerating wear.

Repair strategy: Remove loose surface material to expose a sound base, then apply a UHPC overlay (typically 10-30 mm thick depending on base condition).

Joint Spalling
Concrete edges at saw cuts or expansion joints chip and break, creating damaged areas that worsen over time, affecting forklift travel and generating debris.

Repair strategy: Remove damaged concrete to sound base, install TaiRen armor joint, and fill with UHPC repair material to form a monolithic surface.

Delamination and Settlement
The floor slab separates from the base, creating voids; in severe cases, settlement causes step differences.

Repair strategy: For delamination, pressure grout to fill voids; for severe settlement, remove and replace the slab and base.

---

3. Performance Characteristics of Taiheng UHPC Repair Material

Developed by Shente New Materials in collaboration with Hongri (Zhejiang) Holdings, Taiheng UHPC is specially formulated for floor repair:

• High Early Strength: Under standard curing, reaches over 70% of design strength in 24 hours, enabling rapid return to service. Low-temperature accelerating formulations are available for special conditions.
• High Bond Strength: Tensile bond strength to concrete substrate significantly exceeds that of conventional repair materials, preventing delamination under long-term loading.
• Low Shrinkage: Volume change is much lower than conventional concrete, minimizing shrinkage stress and preventing new cracks.
• Wear Resistance: High surface hardness provides wear life approaching that of new UHPC floors.

---

4. Rapid Repair Construction Process

A key advantage of UHPC repair is speed, minimizing production disruption:

Step	Duration (Reference)	Key Requirements
Surface preparation (milling/grinding/cleaning)	2-4 hrs/100 m²	Sound base, no laitance, adequate roughness
Primer application	0.5-1 hr/100 m²	Uniform coverage
UHPC placement (pouring or hand patching)	1-2 hrs/100 m²	Uniform thickness, smooth surface
Curing to service strength	24-48 hrs	Wet curing, prevent early moisture loss
Return to service	—	After achieving required strength

Note: Times are approximate. For small localized repairs (e.g., a single spalled joint), the entire process can be completed in one shift, with return to service the next day.

---

5. Decision Framework: Repair vs. Replacement

Not all distressed floors are suitable for repair. When distress exceeds a threshold, replacement may be more cost-effective. Use this framework:

Favor repair when:

• Distressed area <30% of total floor area
• Base (concrete subbase and below) is sound, with no widespread delamination or settlement
• Downtime is the primary constraint; long-duration construction is unacceptable

Favor replacement when:

• Base quality is poor, compromising overlay bond
• Owner is planning other major renovations, allowing a unified downtime window
• Floor design standards need fundamental upgrade (e.g., introducing post-tensioning or full-depth UHPC)

BICP technical team can provide professional assessment based on site inspection to help owners make informed decisions.