Prefabricated House Grouting Sleeve

The prefabricated house grouting sleeve is a key component used for steel bar connections in prefabricated buildings. It is assembled from a metal sleeve, special grouting material, and ribbed steel bars, achieving reliable force transfer between steel bars through high-strength micro-expanding grouting material.

Structure and Classification

Grouting sleeves can be classified into two types based on their structure:

1. Full-sleeve grouting: Both ends of the steel bars are connected to the sleeve via grouting material, suitable for scenarios requiring full-section force transfer.
2. Half-grouting sleeve: One end uses threaded connection, while the other is connected via grouting material, combining the advantages of mechanical and grouting connections for higher construction efficiency.

Application Scenarios and Advantages

This technology is primarily used for steel bar connections in vertical components such as prefabricated columns and shear walls, as well as for the “interlocking” connections between vertical shear walls, frame columns, and horizontal frame beams. Its core advantages include:

• Easy installation: Connection is completed through pressure grouting, reducing on-site welding or binding procedures.
• Reliable performance: The hardened grouting material has higher strength than the base material, forming a “steel bar + sleeve + grouting material” three-in-one structure to ensure joint bearing capacity.
• Good earthquake resistance: The micro-expanding property compensates for material shrinkage, preventing loosening at connections and enhancing overall structural stability.

Material and Construction Requirements

1. Material selection:

   • The grouting material must possess properties such as high flowability (for filling narrow gaps), micro-expandability (to compensate for shrinkage), and early-strength and high-strength (to quickly reach design strength).
   • The industry standard Grouting Sleeves for Steel Bar Connections (JG/T 398-2019) specifies material performance requirements, and flowability and compressive strength must be tested before construction.

2. Construction key points:

   • Water-to-material ratio and mixing: Prepare the grouting material strictly according to the ratio and control mixing time to ensure uniformity.
   • Pressure grouting: Use dedicated equipment to inject from the bottom of the sleeve, avoiding air bubble retention and ensuring full grouting.
   • Environmental control: In low-temperature environments, use an adapted formula and maintain curing temperature and humidity with an insulation shed to prevent strength loss.

Core of Quality Assurance

Grouting fullness is critical for connection quality and must be verified through specialized testing (e.g., ultrasonic testing). Parameters such as water-to-material ratio, mixing time, and ambient temperature must be recorded throughout construction to ensure compliance with standards.