MEANING OF GROUTING AND ITS ADVANTAGES
Grouting in civil engineering refers to the injection of pumpable materials into a soil or rock formation to change its physical characteristics. It is one of the ways ground water can be controlled during civil engineering works.
The method of using grout to repair cracks in concrete, fill gaps in tiles, seal joints and stabilize the soil, etc. is called grouting.
Grouting is used to provide additional strength to a building’s foundation and structure. It is also used to repair cracks in concrete, fill gaps in tiles, seal joints, and stabilize soils.
Types of Grouting
In building construction, the material of grouting is prepared in different ways depending on the pile foundation, ground anchor, under reaming, dam construction, road construction, and waterproofing of the building, etc. The types of grouting are as follows:
1) Cement Grouting
Cement grouting is used for high permeability land, for which the grout is prepared using water, sand, and cement.
Use of cement grouting
Cement grouting is used to provide deposit/stabilization and strengthen to a wide variety of structures such as bridges, marine applications, dams, and rock anchors.
The grout material is then injected in liquid form with high pressure to fill the hole in a specified radius around the area used for grouting. The viscosity of the grout material is increased by reducing the water-cement ratio as required. The grouting process is then completed by making a second hole between the primary holes to ensure complete grouting of the area.
2) Chemical Grouting
Chemical grouting is a form of permeation grouting. This type of grouting mix usually includes acrylamides, polyurethanes, acrylates, epoxy, and sodium silicates.
There are two main processes of chemical grouting:
Two-shot Process:
In this process, the pipe is inserted into the ground through a drill. After this, the chemical material is pumped through the pipe in such a way one is followed by another into the soil. So that in the process of a chemical reaction the soil can take a solid form at a rapid speed.
One-shot process:
In this method, a chemical mixture of grouting material is prepared in advance and then poured underground. This process takes time for the structure to harden. A one-shot process of chemical grouting is used for boreholes.
3) Structural Grouting :
A structure is constructed at the site to be mined. Structural grouting is used to fill the gaps between concrete and rock structures and fill the voids between mined materials. Apart from this, structural grouting is also used to fill cracks in rocks and joints of rocks in underground tunnels.
Structural grouting is commonly done in tunnels and underground structures.
4) Bentonite Grouting:
Bentonite is the major component in drilling muds or fluids used in rotary drilling. The suitability of sodium bentonite as a grouting material is 15 times its dry volume when hydrated. Due to its swelling and gel-like permeability property, it is suitable for filling gaps between the casings.
Bituminous Grouting:
Bituminous grouting is also known as asphalt grouting. This grouting technique involves the injection of an asphalt material (similar to roofing tar). The method is almost exclusively used for stopping large inflows (generally greater than 1,000 gpm), although may be used in applications where its elasticity in the cured state is desirable. Bituminous grouting is generally used where void size or water flow is too great to allow other grouting methods to work due to grout washout. The advantage of bituminous grout is that as the hot bitumen is pumped into the ground, eventually, a leading edge of cured, elastic bitumen forms. Additionally grout fills the cured leading edge and expands the grout mass, similar to inflating a balloon. The leading edge forms a protective layer, keeping additional grout from being washed out. Eventually, the mass will grow large enough to either fill the void space available at the injection point, creating a seal within the void.
Bituminous grouting applications are most often associated with mining operations such as quarries or with dams which are experiencing large volumes of seepage. GEC has the capability to design and place bituminous grouts based on the project requirements.
EPOXY RESINS:
Epoxy resins are almost exclusively used for structural grouting. The advantages offered are high strength and bonding capabilities. In grouting applications, epoxy resins are most often used to repair cracks in concrete or to fill other small spaces in structures where strength is required.
Advantage of Grouting:
- Grouting can be used on all types of land.
- In building structures, there is no vibration during grouting or can be controlled so that there is no possibility of deformation of the structures.
- Grouting improves the structure of the site.
- Grouting proves useful in slab jacking i.e. lifting of deformed structure, bearing the load on the structure, etc.
- Grouting is useful in filling the cracks in the walls, pillars.
- It helps in controlling groundwater flow, leakage, and harmful waste materials.
Applications of Grouting:
- It is used to repair machine foundations, base plates, load-bearing, and pillar joints in prefabricated structures.
- Grouting is used to fill gaps, cracks in concrete structures.
- Used for repairing footpaths and the ground under foundations.
- Defects in masonry and cracks in concrete are repaired by grouting.
- Used in soil stabilization.
- Used to control water leakage in mines, tunnels, dams, underground structures.
- Grouting is used to repair unusual and difficult geotechnical and structural problems
- Used to aid in the excavation process.