A technical overview of rubber waterstops. Learn about types (center bulb, dumbbell), materials (EPDM, Neoprene, SBR), and their use in sealing concrete joints against water ingress.
A rubber waterstop is a vital component in concrete construction, designed as a continuous flexible strip. When embedded in concrete joints, it forms a permanent barrier to prevent the passage of fluids, primarily water. Its primary function is to ensure the watertight integrity of concrete structures by sealing the joints against hydrostatic pressure.
As your request, other types including ribbed type, splitting type, base type or capping type can be made to your order.
Rubber waterstops are manufactured in various profiles to suit different joint requirements and expected movements. The most common types include:
· Center Bulb Type: This profile features one or more central bulbs. The bulbs are designed to absorb and accommodate multi-directional movement (such as expansion, contraction, and shear) within the concrete joint, making it suitable for dynamic applications.
· Dumbbell Type: Characterized by its bulbous ends, the dumbbell profile provides superior anchorage within the concrete. This design is highly effective in preventing water from bypassing the seal along the interface between the waterstop and the concrete, ideal for static construction joints.
· Plain Strips: A simple, flat profile used in applications with minimal or no joint movement.
· Steel-Edged Waterstops: A composite product where a rubber waterstop is mechanically bonded to galvanized steel plates. The steel edges provide exceptional tensile strength and anchorage, reducing the risk of displacement during concrete pouring and enhancing performance under very high water pressure.
The choice of rubber compound determines the waterstop's resistance to environmental factors:
Natural Rubber: Offers excellent elasticity and tear resistance.
SBR (Styrene Butadiene Rubber): A general-purpose rubber with good abrasion resistance and a cost-effective profile.
Neoprene (CR): Provides good resistance to weathering, ozone, oils, and flames, offering a balanced set of properties for many applications.
EPDM (Ethylene Propylene Diene Monomer): Known for its superior resistance to ozone, UV radiation, and extreme temperatures, making it the preferred choice for long-term outdoor exposure.
Rubber waterstops are widely specified in concrete structures where water retention or exclusion is critical. Key application areas include:
Water and fluid retaining structures (e.g., Reservoirs, Dams, Water Treatment Plants)
Underground constructions (e.g., Tunnels, Basements, Sewage Tanks)
Civil infrastructure (e.g., Bridges, Culverts, Foundations)
SBR and neoprene rubber, as the most common materials for rubber waterstop manufacturing, are used extensively in United States and the worlds. The SBR water stop is preferred for water containment, while neoprene rubber waterstops are recommend for applications of sewage disposal or chemical industries. As your request, natural rubber, EPDM, Nitrile and Silicone waterstops are also available.
Physical properties | Test methods | SBR | High tensile neoprene rubber | Natural rubber |
Water absorption 2 days at 70°C (% change) | ASTM D-471 | 5% (max) | 5% (max) | 5% (max) |
Hardness shore A | ASTM D-2240 | 65 | 65 | 65 |
Tensile strength | ASTM D- 412 | 3000 psi (min) | 2500 psi (min) | 3500 psi (min) |
Tensile strength at 300% Modulus | ASTM D-412 | 1150 psi (min) | 1150 psi (min) | 1450 psi (min) |
Ultimate elongation | ASTM D-412 | 450% (min) | 450% (min) | 500% (min) |
Compression set 22 hours at 70°C (% original deflection) | ASTM D-395 | 30% (max) | 40% (max) | 30% (max) |
Accelerated aging 96 hours at 70°C (% of tensile strength before aging) | ASTM D-573 | 80% (min) | 80% (min) | 80% (min) |
Accelerated aging 96 hours at 70°C (% of elongation before aging) | ASTM D-573 | 80% (min) | 80% (min) | 80% (min) |
Ozone resistance 7 days at 50 PPHM at 70°C, 20% elongation | ASTM D-1149 | No crack | No crack | No crack |
Selecting the appropriate waterstop involves evaluating several project-specific factors:
Expected Joint Movement: The type and magnitude of movement will dictate the required profile (e.g., center bulb for expansion, dumbbell for static joints).
Hydrostatic Pressure: The water pressure determines the physical strength and design of the waterstop.
Environmental Conditions: Exposure to chemicals, ozone, or temperature extremes will influence the choice of material (e.g., EPDM for outdoor durability).
Installation Method: The waterstop must be compatible with the concrete pouring sequence and securely fixed in place before casting.
Rubber Waterstop Storage
Rubber waterstop should be stored in shade and dry environment, away from sunlight, water, moisture, high temperature, acid, alkali, oil, organic solvent, heat source. The product should be placed vertically, not be pressed by heavy things. The temperature ranges of storage place should be -10°C to +30°C, relative humidity is in the range of 40% to 80%.
Rubber Waterstop Mounting Procedure
The water tightness of the joint is often determined by the way a rubber water stop is installed. The rubber water stop is most vulnerable whilst mounting.
It is important to ensure that the centre of the rubber water stop is placed in the center of the movement/expansion joint and that the rubber water stop does not move in relation to the joint while the concrete is poured. Water stop movement is a particular problem when there are high concrete pressures during the concrete pour.
The concrete underneath the rubber water stop has to be vibrated and consolidated during the pour otherwise porosity, cavities and honey combing will occur.
When the rubber water stop is mounted horizontally the ends should rise upward, in order to prevent air entrapment. The number of longitudinal ridges should also be minimised to reduce the possibility of trapping air under the water stop.
Once the rubber water stop has the concrete poured on one side, the other side needs to be cleaned to ensure it is free of sharp objects.
Health and Safety
· Rubber waterstop: there are no health hazards associated with rubber waterstop normal use.
· Jointing kits: users having sensitive skin are advised to use a suitable barrier cream. Should any solution enter the eyes rinse at once with clean water.
Rubber Waterstop Workshop & Warehouse
Westcoast New Area, Qingdao City ,Shandong Province ,China
