Last Updated on June 15, 2022 by Jose Villegas Jr.
Waterstop is a critical aspect that influences the engineering quality of expansion joints, deformation joints, and construction joints, and it’s exceedingly tough to fix if it’s faulty. As a result, the waterstop’s construction quality is a critical connection that influences the overall project’s quality.
In this post, we looked at the probable causes of rubber waterstop breakage in expansion joints and introduced targeted solutions to assure the project’s overall quality.
The rubber waterstop can fail for the following causes:
Significant Temperature Difference Arises in the Environment
The expansion joint construction takes a long time due to the protracted construction period of large-scale structural buildings. During this time, the temperature differential in the surroundings fluctuates dramatically, and the concrete’s linear expansion coefficient varies proportionally as it expands and contracts freely.
As a result, the concrete causes the liner to expand significantly. The rubber waterstop, on the other hand, fails to respond to such deformation and causes stress concentration, resulting in the weak component breaking.
Construction Mistakes
If the rubber waterstop is not put properly throughout the construction process, air spaces will form on the contact surface between the concrete and the rubber waterstop, causing the rubber waterstop to become loosely bonded to the concrete and potentially peel off due to the air voids.
Large gravels in the concrete will also reach the bottom of the rubber waterstop, causing the rubber waterstop to break owing to the force of the gravels beneath when pouring the upper layer of concrete.
The concrete is not poured at the same time on both sides of the horizontal expansion joint. The second pouring can only take place if the previous-casting part’s concrete strength passes the appropriate specifications. As a result, the rubber waterstop is exposed for a long time.
Steel bar binding and formwork support are required during construction, which necessitates the use of a range of materials. If these materials are not handled appropriately, they can pierce through the rubber waterstop, causing it to break.
Shrinkage of Concrete Expansion Joints
Expansion joints necessitate a lengthy construction period in most cases. After pouring, the concrete shrinks steadily as time passes.
If the concrete shrinkage surpasses the tensile stress of the rubber waterstop at a later stage, stress concentration will occur, resulting in the weak component breaking.
All of the aforementioned factors could lead to the rubber waterstop breaking.
Provided here are the two solutions for rectification of the rubber waterstop breakage:
Method of Chemical Grouting
It is primarily intended to address the issue of concrete expansion joint shrinkage. When solidified, the chemical grouting material has strong adhesion qualities to concrete, as well as good elasticity and hydro-expansibility.
For rubber waterstop fracture repair, we can utilize chemical grouting in combination with an inserted rubber waterstop.
The following are the standard operating procedures:
Before grouting, use a steel file to remove the polyamine board, cracked rubber waterstop, and other debris from the original expansion joint.
Wash the concrete surface to be treated from a distance of 500 mm to make it clean, level, smooth, and debris-free;
Carry out multiple high-pressure pourings into the grouting pipe, as needed;
After pouring, apply anti-corrosion wood strips to the expansion joint surface, followed by jacked steel plates;
Add reinforced concrete baffles and caulking fillers to the exterior surface of the wall expansion joints. Then, around 1 meter from the top of the wall, apply chemical grouting materials to seal the expansion joints, and connect these materials with the rubber waterstop;
When the construction is finished, keep an eye on the expansion joint width as it changes with the temperature and the general change of the building to help with remediation quality control.
Stuffing Technique
The stuffing method is primarily intended to address the issue of rubber waterstop breakage as a result of poor workmanship. Asphalt hemp fiber can efficiently meet the waterproof performance of structures because of its strong hydrophobicity, flexibility, and difficulty in extrusion.
The following are the standard operating procedures:
With a steel file, remove the damaged rubber waterstop and other debris from the original expansion joint;
Wash the concrete surface to be treated from a distance of 500 mm to make it clean, level, smooth, and debris-free;
Drill holes with an electric drill and pre-embed expansion bolts at predetermined intervals on both sides of the expansion joint. The expansion bolt’s specifications will be determined by the real uneven settlement difference. The expansion bolt must be precisely positioned and firmly pre-embedded;
For preliminary water sealing, hammer the processed asphalt hemp fibers into the expansion joint. The depth of the filled asphalt hemp fibers must be adjusted throughout construction to achieve an excellent waterproof effect;
To provide a better waterproof effect, expansion rubber is preferred to cover gaps that are not fully filled with asphalt hemp fibers. The expansion rubber surface must be level with the concrete surface, and the gap between them must be tightly filled.
Finally, clean the concrete surface and check the expansion rubber’s flatness.
Rubber or steel plates can be put on the outside or at the bottom of the expansion joint to suit the waterproofing requirements. The length of the plate utilized must be equal to the joint’s length. The plate’s drilling position and spacing must be identical to the expansion bolt’s.
Waterstop is an important aspect of the construction quality of huge structures, but it is also a weak link. As a result, it is critical to guarantee that all construction standards are met in order to assure the project’s quality. To maintain the project’s service life, proper steps must be made to cope with rubber waterstop breaking and provide a reliable guarantee.