In Australian commercial construction projects, "grout" refers to a fluid mixture used to fill gaps, seal joints, and reinforce structures. It typically consists of water, cement, sand, and sometimes fine gravel or additives to enhance its properties.

Grout is commonly used for:

1. Filling Voids: It fills spaces between tiles, bricks, or stones, providing stability and preventing water ingress.

2. Reinforcement: In structural applications, grout is used to strengthen and stabilize foundations, walls, and other load-bearing elements. It can be injected into cavities or cracks to improve the structural integrity of the construction.

3. Sealing: Grout acts as a sealant to prevent moisture from penetrating surfaces, which is crucial in wet areas like bathrooms and kitchens.

4. Aesthetic Finishing: It provides a finished look to tiled surfaces by filling the spaces between tiles, contributing to the overall aesthetic of the construction.

In commercial projects, the choice of grout can depend on factors such as the specific application, environmental conditions, and the desired properties like strength, durability, and color. Specialized grouts, such as epoxy or polymer-modified grouts, may be used for enhanced performance in demanding environments.