Non-shrink grout is a cementitious material that is used to fill gaps and voids between concrete elements. It is specifically designed to minimize shrinkage during the curing process, which can lead to cracking and other structural issues. Non-shrink grout is commonly used in construction projects, such as building foundations, bridge supports, and industrial equipment installations.
When it comes to non-shrink grout, minimum thickness is an important consideration. The minimum application thickness for this material is ½ inch (13mm), and the maximum is 4 inches (100mm). However, in some cases, it can be applied up to 6 inches (150mm) in depth wihout the need for an extension.
It is important to note that when placing non-shrink grout at depths over 3 inches (75mm) and when the surface area is over 2 square feet (0.19 square meters), the product should be extended. This is to ensure that the grout cures evenly and does not shrink excessively.
In engineering practice, the minimum preferred grout thickness is 25mm. This is recommended by the ACI 351.1R-99, which is a guide for grouting in concrete structures. The thickness of the grout should also be increased by 13mm for each additional 300mm of flow length, up to a maximum of 100mm.
When working with non-shrink grout, it is important to consider environmental factors that can affect its curing process. Water evaporates faster with high temperatures, low humidity, solar heating, and high winds. This can cause the cementitious material to lose water early, before final set, leading to plastic cracking. This is evident by the appearance of fine cracks within hours of application, which can persist for up to 72 hours.
Non-shrink grout is a useful material for filling gaps and voids in concrete structures. Its minimum thickness is an important consideration for ensuring its proper application and structural stability. When working with non-shrink grout, it is important to consider environmental factors that can affect its curing process and to follow recommended guidelines for application.
How Thick Can You Place Non-shrink Grout?
Non-shrink grout can be placed up to a depth of 6 inches (150 mm) without the use of any extension. However, it is important to note that when placing the grout at depths greater than 3 inches (75 mm) and the surface area to be covered is over 2 ft2 (0.19 m2), it is recommended to use an extension. This is to ensure that the grout sets properly and does not shrink or crack over time. It is always advised to follow the manufacturer’s instructions and guidelines for proper placement and use of non-shrink grout.
What Is The Maximum Grout Thickness Under Base Plate?
According to ACI 351.1R-99 and common engineering practice, the recommended minimum grout thickness under a base plate is 25 mm. However, when the flow length (or the distance between the edges of the base plate and the concrete foundation) exceeds 300 mm, the thickness shold be increased by 13 mm for each additional 300 mm. This means that the maximum grout thickness under a base plate is 100 mm.
It is important to note that the grout thickness should be uniform and consistent throughout the entire area under the base plate. Deviations or inconsistencies in the thickness can lead to uneven load distribution and potential failure of the foundation system.
To ensure proper grouting, it is also recommended to use a high-quality, non-shrink grout material that meets the specified strength and durability requirements. The grout should be mixed and applied according to the manufacturer’s instructions, and any air pockets or voids should be eliminated through proper compaction techniques.
The maximum grout thickness under a base plate is 100 mm, but it is important to ensure uniformity and consistency throughout the entire area, and to use a high-quality, non-shrink grout material applied following proper techniques.
Why Does Non-shrink Grout Crack?
Non-shrink grout is a type of cementitious material used for filling gaps, voids, and cavities in concrete structures. Despite its many benefits, non-shrink grout can sometimes crack, which can compromise the integrity of the structure. The main reason for this is the loss of water from the grout before it has fully set.
Water plays a crucial role in the setting and hardening of non-shrink grout. When the grout is mixed, water is added to it to make a paste. This paste then reacts with the air to form a hardened mass. However, if the grout loses water before it has fully set, it can shrink and crack.
Several factors can cause non-shrink grout to lose water early. Firstly, high temperatures can cause water to evaporate faster, which can lead to plastic cracking. Similarly, low humidity can cause the grout to dry out quickly, which can also cause cracking. Solar heating can also cause the grout to lose water early, as can high winds.
When the grout loses water early, it can cause plastic cracking, which is characterized by the appearance of fine cracks within hours of application out to 72 hours. This can compromise the strength and durability of the structure, as well as its overall appearance.
To prevent non-shrink grout from cracking, it is important to ensure that it does not lose water too quickly. This can be achieved by using the correct mix ratio, keeping the temperature and humidity within the recommended range, and protecting the grout from solar heating and high winds. Additionally, it may be necessary to apply a curing compound or cover the grout with a wet cloth to prevent it from drying out too quickly.
Conclusion
Non-shrink grout is a specially formulated cementitious material that is designed to provide excellent performance in a variety of applications. With its low shrinkage and high strength properties, it is well-suited for use in construction projects that require precision and durability. The minimum application thickness is ½ inch, whie the maximum is 4 inches. However, it can be placed up to 6 inches in depth without the extension. It is recommended to use a minimum preferred thickness of 25 mm for optimal performance. Additionally, when placing at depths over 3 inches and the surface area is over 2 ft2, the product should be extended. It is important to be aware of the environmental conditions when using non-shrink grout, as water evaporation can be affected by factors such as temperature, humidity, solar heating, and wind. non-shrink grout is a reliable and effective choice for a variety of construction projects.
