Table of Contents
What Is Honeycomb In Concrete?
This takes place when the mortar doesn’t fill the distance between the coarse aggregate particles. The presence of honeycomb indicates that the first stage of consolidation hasn’t yet been completed at these locations.
Where it shows on the surface, it is necessary to chip out the area and make a repair. Such repairs must be kept to a minimum, mainly because they mar the appearance of the structure.
Honeycomb is caused by using faulty or improper vibrators or by poor vibration Processes. Unsystematic insertions at haphazard angles will cause an accumulation of mortar on the surface while the lower portion of the layer may be under-vibrated.
Sometimes, there are other factors contributing to honeycombs, such as insufficient paste to fill the voids between the aggregate, improper ratio of sand to total aggregate, poor aggregate grading.
improper ratio of sand to total aggregate, improper workability for the placing conditions or insufficient clearance between the reinforcing steel.
In setting steel spacing, both the designer and the builder should keep in mind that the concrete must be consoled.
Honeycomb is a void left in concrete due to the failure of the mortar to effectively fill the spaces among coarse aggregate particles.
Rock pockets are generally severe conditions of a honeycomb where an excessive volume of aggregate is found.
Cause of Honeycomb In Concrete
Primary Causes of Honeycomb
1. Design of Members
- Highly Congested Reinforcement
- Narrow Section
- Internal Interference
- Reinforcement Splices
- Leaking at Joints
- Severe Grout Loss
3. Construction Conditions
- Reinforcement Too Close to Forms
4. Properties of Fresh Concrete
- Insufficient Fines
- Early Stiffening
- Excessive Mixing
- Aggregate That Is Too Large
- Excessive Free-Fall
- Excessive Travel in Forms
- Lift That Is Too High
- Improper Tremie or Drop Chute
- Vibrator Too Small
- Frequency Too Low
- Amplitude Too Small
- Short Immersion Time
- Excessive Spacing Between Insertion
- Inadequate Penetration
Cure for Honeycombs in Concrete
Corrosion is a process that continues through reinforcement rods even into good concrete. This results in losing grip between concrete and sticks, which is very dangerous to the safety and life of concrete structures. Concrete fall should be kept to a minimum.
Honeycombs as a defect not only reduce the load-bearing capacity of concrete; however, water finds a simple method to reinforce rods and rusting, and corrosion starts.
Corrosion is a process that lasts through reinforcement rods even in good concrete, this result in dropping the grip between concrete and sticks that’s very dangerous to the safety and life of concrete structures
Strictly speaking, where honeycombs are detected in concrete, the affected area ought to be broken, and also the portion ought to be reconsecrated after applying grouting chemicals to the old surface.
Honeycombs as a defect not only reduce the load-bearing capacity, but water finds a simple method to reinforce, corrosion, and rods rusting tarts.
Corrosion is a process that continues through reinforcement rods even into good concrete. This results in losing grip between concrete and sticks, which is very dangerous to the safety and life of concrete structures.
In the case of honeycombs on surface pressure grouting with cement-based chemicals that are non-shrinkable Could be adopted after taking the opinion of This designer and acting According to his advice.
Taping with a wooden hammer, the sides of shuttering from outside through concreting and moving will assist in minimizing honeycombs to a great extent in the event of beams and columns.
At places of the junction of beams and columns concrete with strictly 20mm and down aggregates must be used with slightly more cement and water to avoid honeycombs.
The use of a thinner needle says 25mm or less with a vibrator at intricate places of concreting will also help in reducing honeycombs.
Types of Grouting
5 Diffrent types of Grouting Method
- Jet Grouting
- Fracture Grouting
- Permeation Grouting
- Compaction Grouting
- Vacuum Grouting
1. Jet Grouting
Jet grouting uses a high-pressure ‘jet’ force applied of either grout, air, water, or a combination to erode soil whilst simultaneously injecting grout into the soil through a ‘jet monitor.’
The specially designed monitor and drill stem are rotated and raised at the same time to combine the grout with the original soil to form ‘silcrete.’
The end product is cemented round columns and is basically effective in any soil but not necessarily efficient in every soil.
2. Fracture Grouting
This method uses a low-viscosity grout that splits through the ground by penetrating and hydraulic fracturing into the fractures.
The in situ soils are soil displaced immediately next to the fractures and are densified, but to a lesser extent than compaction grouting.
This grouting can also be referred to as compensation grouting and is commonly used to relevel structures.
3. Permeation Grouting
Permeation grouting also called penetration grouting, is the most common and conventional grouting approach. It involves filling any joints, cracks, or voids as in rock, soil, concrete, and other porous materials.
This method’s idea is to fill a void without displacing the formation or creating some change in quantity or configuration from the medium. It is done to strengthen the present formation, creating a water-impermeable barrier, or even both.
There are two forms of permeation injection grout systems: a circulating grout system and also a direct grout system.
4. Compaction Grouting
Compaction Grouting involves an injection grouting of low mobility grout using drill casings that are drilled to pre-set depths.
The grout, usually comprised of sand, cement, water, and fly ash, is placed from the bottom up with pressure-based criteria.
After each consecutive stage, this drill casing is lifted upward until it is entirely taken out. Compaction Grouting is also commonly called Low Mobility Grouting.
5. Vacuum Grouting
This type of grouting to a user in honeycomb time. Vacuum grout sends precise cement salary in concrete.
Interestingly, although grout is typically propelled by pressure, if a void is placed under pressure, then the grout can be ‘sucked’ this is known as vacuum grouting.