1. General Provisions

To ensure the comprehensive performance of the micro-cement flooring system (wear resistance, crack resistance, durability and aesthetic appearance), the substrate shall be constructed to high standards as a structural and functional layer. This specification applies to newly-built rough houses with insufficient reserved floor height (5–8 cm), which require height filling and professional substrate treatment to meet micro-cement construction requirements.

 

2. Core Requirements

- Substrate compressive strength: ≥ 30 MPa (equivalent to C30 concrete grade; C35 or higher is recommended)
Substrate bond strength: ≥ 1.5 MPa
Substrate moisture content: ≤ 8%
Flatness: ≤ 2mm / 2m
Surface condition: Sound and solid, no hollowing, cracks, surface sanding or contaminants
Shrinkage control: Crack-resistant measures are mandatory (such as crack-resistant fiber, steel wire mesh and anchor grooves)

 

3. Standard Construction Procedure

 

Step 1: Substrate Assessment & Preparation

- Structural inspection: Confirm no settlement, cracking or other defects on the original floor slab
Strength testing: Test the strength of the structural layer with a rebound hammer; reinforcement is required if lower than C20
Interface treatment: Shot-blast or grind the original floor to completely remove laitance and form a rough bonding interface
Thorough cleaning: Remove all dust completely with an industrial vacuum cleaner

 

Step 2: High‑Strength Levelling Layer Construction (Core Procedure)

This layer serves as the load-bearing base for micro-cement with a thickness ≥ 5cm, which shall be poured in one single operation.

Item

Requirements & Standards

Material Requirements

Preferred option: Commercial fine aggregate concrete • Grade: ≥ C30, C35 recommended • Aggregate size: 5–12mm • Crack resistance: Polypropylene crack-resistant fiber (0.9–1.2kg/m³) shall be added Alternative option: Site-mixed fine aggregate concrete (must be mixed by small mixer; manual mixing is strictly prohibited) • Cement: P.O 42.5 • Mix ratio (weight): Cement : Medium sand : Fine stone = 1:1.3:2.5 • Water-cement ratio: ≤ 0.42 • Mandatory addition: Crack-resistant fiber + Steel wire mesh (Φ4@200×200)

 

Step 3: Crack-Resistant Layer Construction (Key Procedure)

 

1. Fiberglass Mesh Cloth

- Material: 160g/m² alkali-resistant fiberglass mesh
Construction: Apply epoxy resin → lay mesh cloth → second coating
Overlap width: ≥10cm

2. Crack-Resistant Mortar Layer

- Material: Polymer crack-resistant mortar
Thickness: 2–3mm
Curing: Grind flat after 24 hours of curing

 

4. Substrate Acceptance Criteria (Before Micro-Cement Construction)

Testing Item	Standard Requirement	Testing Method
Compressive Strength	≥30MPa	Rebound hammer / Core sampling test
Bond Strength	≥1.5MPa	Pull-off tester
Moisture Content	≤8%	Moisture content tester
Flatness	≤2mm/2m	2m straightedge + feeler gauge

 

5. Precautions

- Micro-cement construction is strictly prohibited on unqualified substrates
Ordinary cement mortar is forbidden to be used as levelling layer
Construction is not allowed before the substrate reaches sufficient curing period
A complete crack-resistant system must be implemented
Full substrate acceptance inspection is mandatory
Construction ambient temperature: 15–30℃
Ambient humidity: ≤75%
Substrate surface temperature: ≥10℃

 

6. Common Problems & Solutions

1. Substrate cracks: V-groove cutting → filling with epoxy mortar → laying anti-crack tape
2. Partial hollowing: Drilling and grouting → pressure curing → surface restoration
3. Insufficient strength: Surface treatment → applying concrete hardener → re-inspection
4. Excessive moisture content: Extend drying time → forced ventilation → underfloor heating temperature rise

 

7. Quality Liability

- The substrate contractor shall take full responsibility for substrate quality
The micro-cement constructor must inspect and accept the substrate before construction
Subsequent procedures shall not commence if acceptance fails
A 《Substrate Acceptance Handover Form》 shall be filled and signed by both parties

Specification Basis:

1. GB 50209-2010 Code for Acceptance of Construction Quality of Building Ground Works
2. JGJ/T 175-2018 Technical Standard for Self-Leveling Flooring Engineering
3. Technical requirements of micro-cement manufacturer
4. Summary of engineering practice

This specification serves as the fundamental document for the construction of micro-cement flooring systems and shall be strictly followed by all relevant parties. The content will be continuously updated and improved along with technological progress and engineering practice.

Shenzhen Simon United Building Materials Co., Ltd.