Special Grout: The Secret Weapon for Building Reinforcement

1. What is Grout?

According to the standard JC/T 986-2018 "Cement-based Grouting Materials," grout is a mixture of cement, aggregates, and additives that exhibits excellent fluidity and injectability. It is typically used to fill voids, reinforce structures, enhance load-bearing capacity, and improve sealing properties.

2. Composition of Grout

The composition of grout mainly includes: binding materials, expansion components, early strength components, water-reducing agents, water-retaining thickening components, and aggregates.

Binding materials: Cement (including Portland cement, aluminum cement, and sulfoaluminate cement), fly ash, mineral powder, and microsilica;

Expansion components: Gypsum, sulfoaluminate calcium types, calcium oxide types, sulfoaluminate calcium-calcium oxide types, and aluminum powder as expansion agents;

Early strength components: Sodium sulfate, lithium chloride, and lithium carbonate as early strength aids;

Water-reducing components: Naphthalene-based water reducers and polycarboxylic acid water reducers as high-efficiency water reducers;

Water-retaining thickening components: Cellulose ether and redispersible latex powder;

Aggregates: River sand, mountain sand, and manufactured sand.

3. Characteristics of Grouting Materials

The standard JC/T 986-2018 "Cement-based Grouting Materials" outlines the technical specifications for grouting materials, primarily distinguishing between the workability and strength of the mortar.

1. High Strength: Grouting materials possess high strength, effectively reinforcing and enhancing the load-bearing capacity of structures.

2. Self-Flowing: They can flow on their own, filling narrow spaces and cracks, ensuring uniformity and density in the grouting process.

3. Early Strength: Grouting materials set and harden quickly, achieving the required strength in a short period.

4. Durability: They exhibit excellent durability, resisting weathering, corrosion, and chemical attacks.

5. Workability: Easy to apply, with simple operation, they can be used through pouring or spraying methods.

6. Micro-Expansion, No Shrinkage: Ensures tight contact between the equipment and the foundation.

4. Classification of Grouting Materials

Grouting materials can be classified based on different criteria, with some common classification methods outlined below:

1. By Composition: Grouting materials can be categorized into cement-based, epoxy resin, and polyurethane grouting materials, each with distinct performance characteristics suitable for various engineering needs.

2. By Application: Depending on their use, grouting materials can be divided into equipment installation, structural reinforcement, and waterproofing grouting materials. Each type emphasizes different performance aspects.

3. By Flowability: The flowability of grouting materials is typically indicated by flowability metrics, classifying them into self-leveling, high-flow, and low-flow grouting materials. Variations in flowability affect the construction performance and filling capacity of the materials.

4. By Early Strength: Early strength is a crucial performance indicator for grouting materials, allowing for the distinction between early-strength and standard grouting materials. Early-strength materials can reach the required strength quickly, making them suitable for projects with tight schedules.

5. By Compressive Strength: Grouting materials can be classified into low, medium, and high-strength categories based on their compressive strength. The level of compressive strength directly influences the effectiveness of grouting materials in structural reinforcement.