Waterbar Application Manual

DISCLAIMER The product information & application details given by the company & its agents has been provided in good faith & meant to serve only as a general guideline during usage. Users are advised to carry out tests & take trials to ensure on the suitability of products meeting their requirement prior to full scale usage of our products. Since the correct identification of the problems, quality of other materials used and on-site workmanship are factors beyond our control, there are no expressed or implied guarantee / warranty as to the results obtained. The Company does not assume any liability or any consequential damage for unsatisfactory results, arising from the use of our products.

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from the makers of

Pidilite Industries Limited

Construction Chemicals Division

Ramakrishna Mandir Road, PO Box No. 17411, Andheri East, Mumbai 400 059 T 2835 7000 F 2835 7008

drfixit@pidilite.com, www.doctor-fixit.com

• General description of Waterstops and their usage

• Existing methods of sealing joints and problems associated with them

• An explanation of Strip type waterbars

• Advantage of Dr. Fixit Waterbars

• Detailed instructions on how to lay Dr. Fixit Waterbars

• Frequently answered question (FAQ) on waterbars

• Comparision table for different types of strip waterbars

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Existing Methods of Sealing Construction Joints and common problemswith such methods

• PVC Waterstops

PVC waterstops are available in various sizes in width and various thicknesses. One half of the waterstop is inserted into fresh concrete during concreting.The other half is normally concreted in the second phase of concreting. It is believed that this waterstop helps in increasing the flow path of water around it thus lowering its pressure. Experience shows us that PVC waterstops do not bond with the parent concrete due to nonhomogenous nature of the PVC and the concrete.It is very difficult to keep the PVC waterstop in position while concreting is underway, especially if there is obstructing reinforcement bars. When the second lift of concrete is poured, the second half of the PVC waterstop generally folds over and helps to form a passage through which even more water may leak. It is difficultto weld PVC waterstop on site if a welding machine is not available.

• Epoxy Coatings in Construction Joints

Although some nonengineers have suggested epoxy coating as a solution to the problem of sealing gaps in construction joints, this system will not work since epoxy forms only a thin coating and does not fill the gap. It is useful only when structural bonding is required. Gaps in construction joints may be quite large (upto 5-6 mm) and cannot be filled up by epoxy coating. In addition to sealing

the construction joint with a waterbar to prevent leakage, your structural consultant may still recommend that you apply epoxy coating above and below the waterbar so as to ensure structural bonding.

• Cement Grouting

Cement grouting into construction joints is one of the methods which is used regularly by engineers in the attempt to fill up construction joints. This works well if there is a large amount of honeycombs in the concrete. However, if there are no honeycombs and there is onlya thin gap in the joint, then it becomes very difficultto grout since the slurry cannot find its way into the fine gap. Moreover, drilling a number of holes directly intoa joint will actually make the joint weaker and not help much in sealing the joint.

• Epoxy, P. U, acrylic or other chemical grouting

Epoxy grouting also has the same problems as cement grouting. If drilling and fixing a grout nipple can be executed well, then this method has a higher degree of success as compared with cement grouting. However, epoxy or any other kind of chemical grouting is very expensive and it is difficult to find experienced applicators to carry out such jobs.

The correct solution to sealing construction joints in water contact structures is a STRIP WATERBAR OR STRIP WATERSTOP.

A strip waterstop looks like a rope. Strip Waterstops typically have a square or rectangular cross section of sizes like 5 mm x 20 mm, 10 mm x 10 mm, 10 mm x 20 mm, 19 mm x 25 mm, 20 mm x 20 mm, 25 mm x 25 mm etc. They are made of different materials like hydrocarbon based polymer , hydrophilic rubber, bentonite base, butyl rubber and other materials. Generally they are divided into two categories: NonSwellable (Compressible) Waterstops and Swellable Waterstops or Waterbars.

• Nonswellable Waterbar

A noneswellable or compressible waterbar works on the principle of compression and sealing the joint. When concrete falls on the sealant, it gets compressed and by virtue of this the gap or construction joint gets filled up. For this, the essential properties are compressibility, i.e. the waterbar should be slightly soft so that it gets compressed. It should be able to change its shape and squeeze itself to fill up the gap. It should be of fairly large cross section so that there is enough material to get squeezed. If for eg, the cross section is only 5 mm x 10 mm or 10 mmx 10 mm, there may not be enough material to get compressed. Typically, compressible sealants should be of 20 mm x 20 mm cross section minimum for maximum effectiveness. If it is 25 mm x 25 mm, it is even better.

Compressible (Nonswellable Waterbars) require very less cover in concrete. They can be used with cover as less as 25mm. The minimum strength of concrete can also be as low as M15 since there is no danger of expansion of sealant.

An important requirement of compressible waterbars is a highly adhesive nature. This is required because freshly poured concrete should adhere immediately with the waterbar. When shrinkage of concrete occurs, the waterbar is still stuck to the concrete and no gap occurs because of the shrinkage.

Compressible waterstops are generally useful to stop water leakage having a maximum head of about 15 to 20 mtrs.

• Swellable Waterbars

A swellable waterbar works on the principle of swelling upon coming into contact with water. If there is no water, it does not swell at all. Typically, they are made of hydrophilic rubber or are bentonite based materials.

• Pure rubber Hydrophilic Waterbar

Let us look at such a waterbar which is commonly available in the market today. Such a waterbar is of small cross section say 5 mm x 10 mm or 10 mm x 10 mm and expands to 200 percent of its volume on contact with water. Such waterstops are fairly rigid before expansion and also after expansion. They retain most of their cross section even after expansion. If it is immersed in water and then taken out after a few days, it is not possible to squeeze it in your hand and change its shape. These waterstops work well in straight joints and where there is no irregularity in the gap.High Expansion pressure: Because hydrophilic rubbers expand so much (250-300 percent), they are generally manufactured using small cross sections like 5 mm x 10 mm, 10 mm x 10 mm, or 5 mm x 20 mm. This ensures that there is not too much expansion volume and

Waterbar Application Manual

1] What are waterbars or waterstops and where are they used in civil engineering?

All structures built of concrete have construction joints. These may be horizontal joints, vertical joints, inclined joints or curved joints. By themselves, they do not pose any serious problems. However, if the structures are subject to water pressure, improperly cast joints may cause problems because of leakage. This may happen in water tanks, basements, tunnels, swimming pools, water treatment plants etc.

Such structures include Water Tanks, Swimming Pools, Basement Wall and Floor perimeter joint, Basement column and floor slab joint, vertical joints in basement retaining walls, Sewage Treatment Plants, Sump Tanks, Potable water Reservoirs, Raft Slabs cast in more than one pour, final roof slabs cast in more than one pour, pipe intrusions in concrete walls, fish hatcheries, concrete lined storm water and irrigation channels, precast structures such as box culverts, septic tanks and utility vaults, pedestrian and below grade tunnels, but joint between old roof and new roof and other joints.2] Why does leakage occur?

Leakage occurs when there is a gap in the construction joint. This gap occurs when it is not possible to vibrate concrete properly and effectively within the construction joint due to various difficulties under site conditions. Such a gap can also occur due to shrinkage of concrete. Shrinkage gaps may vary from 0.5 mm to 1mm. Gap due to inadequate vibration may vary from 1-6mm.

3] How do we solve this chronic problem?

Various attempts are made by engineers to solve this problem.

Some engineers suggest the use of PVC waterstops during concreting. Some apply epoxy to the construction joint. Some prefer to grout the joint with cement slurry or epoxy injection. Let us evaluate all these systems one by one.

TYPICAL

WATER MAY LEAK ALONG

THE PATH SHOWN IN RED

PVC WATERSTOP FOLDING

OVER WHEN CONCRETE

FALLS ON IT

PROBLEMS WITH PVC WATERSTOPS

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site conditions cause problems and the waterstop expands even before you concrete it. In that case, the SW2020 waterstop behaves like a flexible compressible waterstop. Its large cross section again comes into play and the material squeezes itself into the construction joint and again makes the joint watertight. This is why it is called a “2 in 1 Waterbar”.

Detailed laying instructions(READ CAREFULLY BEFORE USING DR.FIXIT WATERBAR)

• Positioning of waterstop in the joint is very important. Please refer to the section on SKETCHES in the waterbar application manual to see exactly how waterstop is to be placed.

• Cleaning of joint of loose concrete, debris, dust and loose mortar is very important.

• ALWAYS CHECK the carton to make sure which waterbar you are using Swellable or Nonswellable. Please note that instructions for laying Swellable and Nonswellable waterbar are different. Please refer SPECIFICATION in the TECHNICAL DATA SHEET.

• Do not stretch or pull the Dr. Fixit Waterbar and make it longer than its existing length. If you do this, then the effectiveness of the waterbar will reduce drastically and it will not be able to seal the joint properly.

• Dr. Fixit Nonswellable Waterbar NSW2525

Dr. Fixit Nonswellable Waterbar NSW 2525 is a compressible waterbar with a large cross section.

Unlike other hydrophilic Rubber waterbars which are commonly available, NSW 2525 is highly adhesive in nature. This nature allows it to bond by adhesion to

Advantages of Dr. Fixit Waterbars

Waterbar Application Manual

consequently high pressures which may “blow out” the joint.

For the same reason, manufacturers advise that the minimum cover required in concrete when you use such materials is about 75– 100 mm. Also the grade ofconcrete should not be less than M20. Some manufacturers even advise M25.

It is important to see that Premature Expansion Problem:expansion does not take place even before you place concrete. To solve this problem, some manufacturers coat their waterstop with a “Delay Coating” which slows down the rate of swell of the waterstop. This means that the waterstop expands slowly.

Such a waterstop Bentonite based Swellable Waterstop:relies highly on its considerable bentonite content to expand. This is uncontrolled expansion. If immersed in water, it will expand to the point that it will change its shape completely and may even fall apart. If water pressure is high, sometimes there is a chance that it might even get washed away.

Swellable waterstops are designed for higher waterheads. They are typically used when you want to resist water heads of about 50 to 100 mtrs.

Badly compacted concrete above or below a construction joint can still leak in spite of using the best quality waterbar

freshly poured concrete. It is extremely difficult to remove NSW2525 from set concrete. This property helps when concrete shrinkage takes place. The waterstop is pulled by the concrete and shapes itself into the new space.

NSW 2525 is larger than most other waterstops in the

market. It his highly flexible and therefore can be moulded into the construction joint when concrete falls on it, thus filling up the construction joint completely and making the joint waterproof.

NSW 2525 is completely unaffected by water and hence can be used in situations where there is a danger of curing water or rain affecting the work. It can be used even when the cold joint is wet or curing water has stagnated. However, loose mortar and laitance should be removed physically before using NSW 2525.

NSW 2525 is recommended to be used where it is necessary to resist water heads of upto 15 to mtrs.

• Dr. Fixit's Swellable Waterbar SW 2020

SW 2020 is the hydrophilic swellable waterbar of Dr. Fixit. It is also known as a “2 in 1 Waterbar”

SW2020 first acts like a compressible waterstop because of its large cross section and because of its flexible nature. It immediately makes the joint water resistant to a waterhead of about 20 mtrs. Next, it starts expanding when it comes into contact with water and then increases the resistance to water leakage upto a head of 60-80 mtrs. This is why it is called a “2 in 1 Waterbar”.

SW 2020 is a “Controlled Expansion” waterstop. It does not swell to the point of deterioration. It is designed to swell upto a maximum of 150 percent over and above its original volume. By this, it ensures that there is no unnecessary pressure generated inside the joint due to high expansion. Hence concrete cover can be as less as 50 mm when using SW2020. It also ensures that it does not expand so much that it gets washed out from the joint in case there is a large gap.SW 2020 has a large cross section of 20 mm x 20 mm. Thus, it has the great advantage that compressible waterbars have. A large cross section which ensures that there is enough volume to begin with which can get compressed. SW 2020 is a flexible material unlike regular hydrophilic rubber waterstops which are rigid. Note that rigid waterstops cannot be compressed easily.

Unlike other hydrophilic Rubber waterbars which are commonly available, SW 2020 is highly adhesive in nature. This nature allows it to bond by adhesion to freshly poured concrete. It is extremely difficult to remove SW2020 from set concrete. This property helps when concrete shrinkage takes place. The waterstop is pulled by the concrete and shapes itself into the new space. SW 2020 is fault tolerant waterstop. Let us assume that

Before swelling After swelling

Effect of SW 2020placed in a pipe &immersed in water

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LAYING DR. FIXIT WATERBAR-METHODOLOGY

CLEAN THE JOINT APPLY PRIMER 20mm WIDE

UNCOIL DR. FIXIT WATERBAR PLACE IN POSITION

POUR CONCRETE FINISHED WATERPROOF JOINT

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Waterbar Application Manual

TYPICAL PLACEMENT OF WATER BAR IN

CONSTRUCTION JOINTS OF BASEMENT OR CELLAR

SECOND POUR

SECOND POUR

FIRSTPOUR

Vertical Joints in raft slab

(Sketches)

VERTICAL JOINT - HANGING WATERBAR

USING BINDING WIRE OR STRING

IF IT DOES NOT STICK TO PRIMER

Cut away view showing Dr. Fixit Waterbar inside a typical horizontal construction joint

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Frequent questions

• Question: You have two types of waterbars. One is swellable and the other is nonswellable. Which should I choose for my project?

The choice of waterbar depends on various Answer:factors. The first and primary characteristic is the waterhead that it has to resist in your structure. If you have a high waterhead, you will choose the swellable type. If you have a low waterhead, you will choose the nonswellable type. If you are not sure how well you will be able to vibrate in the construction joint area, you will choose the swellable type. If you are fairly certain about your concrete quality compaction just below and just above the construction joint, you will choose the nonswellable type. However, in view of the fact that the price difference is very less between the swellable and the nonswellable waterbar in Pidilite, it may be advisable to choose the swellable type since it offers significantly more benefits.

• Question: Some waterstop companies claim that their waterstop is better because it resists a waterhead of 100 mtrs. Is that of better quality?

You need to buy a waterstop that fits your need Answer:and your budget. If your structure has to resist only 15 mtrs waterhead throughout its entire life, there is no need to pay a very high price and buy a waterstop which can resist 100 mtrs waterhead. However, if you are able to get a waterstop which will resist a very high pressure and at the same time costs very less, then buy it.

• Question: Our consultant has specified that the waterstop has to expand in volume by 300 percent so that it will work well. Does your swellable waterstop swell by 300 percent?

Generally the gap in construction joints varies Answer:from 0 mm to 4 mm. More the waterstop swells, more the pressure that is exerted inside the concrete. For this reason, uncontrolled expansion is generally not preferred by knowledgable engineers. Dr. Fixit Waterbars are designed to swell by 150 percent more than original volume which is the specified standard in many advanced countries. This “Controlled

Swelling” property of Dr. Fixit Waterbar is a patented

process which exerts less pressure on the surrounding concrete and is the preferred specification today.

• Question: Will the Waterbar become hard or deteriorate with time?

Dr. Fixit Waterbar is designed to remain flexible Answer:for the lifetime of the concrete. It will not deteriorate with time. It will last the lifetime of the structure.

• Question: Is it compulsory to make a keyway or groove and then place the waterbar?

No, it is not. The waterstop will work effectively Answer:even if there is no keyway as long as there is enough head of concrete on top to “press” the waterbar. This is especially important in the case of the nonswellable waterbar. For best results, the recommended head of concrete for nonswellable waterbar is 400 mm and for swellable waterbar, the head can be as low as 150 mm.

• Question: How do I know if the waterstop I have used in my project is the original patented Dr. Fixit Waterbar or not? It is always advisable to buy from any of our Answer:

registered dealers. That way, you are assured of getting the original waterbar. There are instances when fake waterbars made of cheap black material will be shown as Dr. Fixit waterbar or equivalent. Only when the waterbar fails will you know that the product has caused you enormous problems. But by then, it may be too late. It is always advisable to buy the original product and be 100 percent sure.

• Question: Is Dr. Fixit waterbar competitive in price compared to other waterbars in India?

Compare our product with any other waterstop Answer:available in the market. When others give smaller cross sections of 10 mm x 10 mm or 5 mm x 20 mm, Pidilite is offering a cross section of 20mm x 20 mm for the same price as others. i.e. you are getting a waterstop which has three times the volume which also means that the price is nearly one third that of competitors for the same category.

• Question: How is it that Dr. Fixit waterbar is priced lesser than other competitor's products?Answer: Pidilite is able to give this technically advanced “Controlled Expansion” Waterbar at such a low price by manufacturing it in large quantities.

Waterbar Application Manual

• Question: In hot weather, will Dr. Fixit waterbar become soft and melt?

No, the unique structure of Dr. Fixit Waterstop Answer:ensures that it does not melt and flow in hot weather, unlike other waterstops.

Comparision with other similar

products DR. Fixit Waterbar SW 2020 is the only hydrophilic

rubber swellable waterbar having such a large cross section. Cross section of SW 2020 is 20mm x 20 mm = 400 sq mm. Other waterbars are of much smaller cross section.

Dr. Fixit Waterbar NSW 2525 is made of superior material made with the latest technology in the USA in international standard extruding machines. The manufacturing process complies fully with ISO 9001.

No. Property Compressible Other Regular Pidilite’s special 2 in 1 (Nonswellable Waterbar) SwellableWaterbar Controlled Expansion Waterbar SW 2020

1. Concrete Grade Can be used in concrete grade Preferable to use in concrete Can be used in concrete grade as low as M15 or M20 grade M 25 and above only from M20 to M40

2. Cover required 20 mm 75 mm 50 mm

3. Size available Generally 20 mm x 25 mm Typically Big size (Bigger the better) (500 sq. mm.) 5mmx10mm 20mmx20mm (400 sq. mm) 10mmx10mm Value for money 5mmx20mm

4. Expansion None 250 to 300 150 over and above (More need not original volume necessarily be better, please read detailed literature on this)

5. Technology Proven technology. Has been Swelling technology better Next higher level in used for many years. than compressible waterbars technology after swelling technology

6. Water Head which 15-20 mtrs 50-100 mtrs 60-80 mtrs it can resist

7. Flexibility and Very good Fairly rigid Very good compressbility

8. Dual Role of No No Yes compressible and swelling waterstop

9. Availability Available always Not available always Available always

10. Technical Backup Always available from Pidilite. Not available always Always available from Pidilite. Separate division formed to Separate division formed to service this market service this market 11. Offering Full range Pidilite offers entire range Competitors do not offer Pidilite offers entire range of waterstop entire range

Comparision of Different types of Strip Waterbars (User Guide)

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Notes