Q1. How to prepare the surface of the RCC substrate before carrying our waterproofing?
A1. First of all clean the RCC substrate of all oil, grease and loosely adhering particles. Then repair the RCC with rich cement-sand mortar and DURAKRIT if there are any crack )more than 1 mm wide), pinholes, etc., as per the literature of DURAKRIT. Finally, make mortar gola using DURAKRIT along the horizontal and vertical edges, other projections as per the specification of “Mortar Gola”.
Q2. How to go about waterproofing of terrace?
A2. First prepare the surface as given in Q1. The terrace surface should be dampened by spraying water preferably overnight and allowing it to stand. Next day the standing water should be removed so that it is Saturated Surface Dry (SSD). Then waterproofing should be carried out by applying the 3 coats of DURAGARD taking care the subsequent coat is applied after the previous coat is touch dry. Use of glass fibre mesh is highly recommended. Provide a protective coating of 1:4 cement sand mortar.
Q3. Are there chances of the terrace being damaged from welding rods or materials with sharp edges despite waterproofing?
A3. Yes, the terrace may be damaged from external sources despite using DURAGARD. For precautionary means, a protective plaster 1:5 (cement:sand) admixed with DURA 1 should be provided with thickness varying from 12mm to 20mm.
Q4. How to waterproof static cracks?
A4. Method of waterproofing same as Q2.
Q5. How to waterproof dynamic cracks?
A5. First find the extent of cracks. Prepare the surface. For hairline cracks, 2 coats of highly flexible material DURAFEX may be provided with a non woven fabric/ polyester acting as a reinforcing agent between the 2 coats. The protective plaster is a must in this case. For wider and deep cracks, the primer DURACRYL MP should be applied first followed by DURAFEX coating.
Q6. How to carry out waterproofing of:
(i) Overhead water tank
Concreting: During concreting DURA 1 shall be added, 2% weight of cement to increase durability and reduce permeability. On the existing surface, DURAKRIT: Cement sand (1:1) slurry should be mixed in the ratio 2:1 to 3:1. The green concrete should be placed before the above slurry dries.
Coating: Then prepare the surface as per Q1. For waterproofing interior walls of the tank, 2 coats of DURAGARD may be applied. Protect the coating by laying glazed tiles/ cement sand plaster, etc.
In case of honeycombs/voids, our non-shrinking expansive grout, DURA EV may be used.
(ii) Swimming Pool
Concreting: During concreting DURA 1 shall be added, 2% weight of cement to increase durability and reduce permeability. On the existing surface, DURAKRIT: Cement sand (1:1) slurry should be mixed in the ratio 2:1 to 3:1. The green concrete should be placed before the above slurry dries.
Before the construction of the RCC base slab of pool, repair the surface of PCC by 1:4 cement sand mortar. Apply 2 coats of DURAGARD and protect the coating with 1:4 cement sand mortar of about 20mm thickness.
After retaining wall and base is cast, prepare the surface as per Q1. Then over the levelled surface, 2 coats of DURAGARD should be applied with a glass fibre mesh used as reinforcing agent between the 2 coats. Next, another coat of DURAGARD should be applied on top of which the tiles should be placed. The tile joints must be sealed using DURATILOFIL.
In case of honeycombs/voids, our non-shrinking expansive grout, DURA EV may be used.
(iii) Terrace Garden
Mother Slab should be treated as per Q2 followed by a protective plaster. Then lay the stone tiles i.e. Kota /sand stone on top of it using DURAFIX 2P (Tile adhesive). Put DURAKRIT-CEMENT MORTAR along the joints of the tiles to make the surface aquaproof. Finally gardening may be carried out as per desire to cultivate plants, flowers, vegetables, etc.
(iv) Underground water tank
The procedure is same as Swimming pool except for the fact that DURAGARD coating is given from both inside and outside.
(v) Basement (Pre construction)
The procedure is same as Swimming pool except for the fact that DURAGARD coating is given from the outside.
Q7. Rain water enters inside the rooms of building through walls. How can we waterproof external walls?
A7. The external wall surface should be impregnated/ applied with 2 coats DURAPEL W/S.
Q8. In a flat system upper floor bathroom is leaking and causing dampness & efflorescence of the room wall underneath. What is the solution without disturbing the upper floor residents?
A8. This problem could be sorted out by 2 ways:
(a) By fixing nozzle at 0.3m apart in the wall, grouting should be carried out with a mixture of DURAKRIT-CEMENT and Water followed by application of DURAKRIT-CEMENT slurry.
(b) This is an ideal situation for application of materials with crystallization property like DURACRIST. 2 coats of DURACRIST+Water would be sufficient to arrest the leakage.
Q9. What is the solution for:
(i) Preventing the flow of water from the water tank in the form of jet.
(i) Our instant plugging compound like Dura 2 is very useful in this situation in conjunction with cement. (Check out the Dura 2 literature for application details)
(ii) Avoiding the sweating of walls.
(ii) This could be prevented by using our moderate setting compound like Dura 3 in conjunction with 1:2::Cement: sand mortar.
(iii) Preventing the continuous flow of water inside the tunnel
(iii) The flow of water could be stopped by injecting DURAJEL through the nozzle against water flow.
(iv) Stopping the flooding of the basement area in case of heavy downpour.
(iv) The water needs to be pumped out from the basement area. This can be done by forming a sump pit so that the area is devoid of water through pumping. Now the pores of the diaphragm walls need to be filled with DURA EV (expansive grout) plus cement.
Q10. In the ground floor of flats, often dampness upto 3 feet height of wall has been observed which cause the spalling or removal of wall plaster and paint. How to counteract such a problem?
A10. The rise of water upto 3 feet is due to the capillary action. The plaster should be removed from the affected area. Nozzle should be fixed in staggered pattern 0.3 m apart and DURAINJECTO should be injected through the nozzle. This would permanently destroy the capillary pores. The entire area should be plastered again using cement sand mortar admixed with DURAKRIT.
Q11. Often cold/ construction joints are formed whenever fresh concrete surface is laid on top of old concrete surface. How do we avoid the formation of such joints?
A11. This can be rectified by using DURAKRIT plus 1:1 cement sand mixture slurry before pouring the fresh concrete. If the construction joints already exist, then a rectangular groove upto 10 mm by 10 mm should be cut along the joint followed by filling up the groove with DURAKRIT-cement sand slurry.
Q1. Although curing on the horizontal surface is facilitated by flooding the water by bunding along the periphery, curing on the vertical surfaces like chimneys, high rise buildings is difficult. So how can curing on vertical surfaces be carried out? OR
How to carry out curing in areas like Middle East or mountainous regions where water is in shortage?
A1. Our curing compounds like DURACURE is ideal in such cases. The vertical surface has to be sprayed with DURACURE
Moreover, use of DURACURE is also recommended for construction activities carried out in water scarce regions.
Q2. Sometimes the top surface of the concrete is exposed to high solar energy which causes it to crack due to fast evaporation of surface water. What is the solution?
A2. DURACURE WP which is having solar reflective pigments (reflects 60% of the heat) can be used in such cases.
SHUTTERING RELATED FAQS
Q3. Generally engineers prefer use of mobil oil, cow dung as a shutter release agent to reduce cost. But often such agents due to the presence of organic impurities which are acidic in nature cause scouring of concrete surface. Moreover use of such agents give a poor coverage of around 5-10 m2 per litre and forms a stain/pitting on the surface. What other alternatives do we have?
A3. Due to scouring effect on the surface, painting or any other surface treatment becomes difficult. Under such a situation, DURAMOL, a high quality mould release agent can be used with better release property.
In addition to its release properties, DURAMOL also gives a coverage of 40-50 m2/litre and provides a fair faced concrete free of any blowholes/pitting.
BONDING RELATED FAQS
Q4. How can structural members be joined to each other? How can cantilever extension be carried out from the existing surface?
A4. Here the use of structural adhesives like DURAXYBOND is recommended. It is applied on the existing surface followed by placing fresh concrete
Q5. Do you have any products for joining structural members as in the case of segmental bridge construction?
A5. Our segmental bridge adhesive i.e. DURAXY SBA can be used in such cases.
SILICONE IMPREGNATION RELATED FAQS
Q6. Sometimes efflorescence/ dampness can be noticed inside the room of a building after a heavy downpour. How can such a problem be arrested?
A6. This can be stopped by coating the external wall of the building with DURAPEL W/S used as a raincoat.
Q1. Some engineers feel admixtures added to concrete may improve physical properties but are detrimental in the term long term durability of concrete. Is this true?
A1. The above statement is misleading especially in reference to detrimental properties so as to when admixtures are added to concrete. Infact, proven admixtures based on lignosulphonates (LS), naphthalene sulphonates (NSF), melamine sulphonate (MSF), polyhydroxy carboxylic acid salts, poly carboxylate and poly carboxylate ether would not only improve the properties like increase and maintenance of slump, cohesion of concrete, reduction of bleeding, ease of compaction but also lead to ultimate durability of concrete in both fresh and hardened states.
Q2. How should we choose admixtures for a particular use?
A2. Choice of admixtures depends on the purpose of its use:
a) For simple increase in the workability, use DURASPRED N. Typically slump may be increased by 100% at a dosage rate of 0.5% by wt. of cement. This slump may last for 15 minutes. If you wish to have maintenance of slump for a longer period, such requirement should be brought to our notice so that tailor made solution may be provided.
b) For increase in strength by 15-20%, water reduction upto 10% may be carried by adding DURASPRED N.
c) Cement saving upto 10% is also possible by maintaining the same W/C.
Note: While using DURASPRED N, all the three advantages as mentioned above can be achieved at once but that would require a little compromise in the strength increase and water/cement reduction.
Q3. Where should we use DURASUPASPRED?
A3. DURASUPASPRED is available in 2 versions, i.e., normal i.e. DURASUPASPRED and retarded i.e. DURASUPASPRED 500/ 400C.
The normal version may be used for high slump concrete which has to be used in 10 mins. Also super water reduction can be achieved which would result in 25-30% strength development very quickly.
The retarded version may be used where slump has to be maintained for a longer period of time and strength development needs to be gradual. It is highly useful for pumping concrete.
Q4. What is the purpose of using DURAMICROSILICA?
A4. It is used where it is difficult to achieve the desired strength of concrete especially for high strength concrete M50 and above.
Q5. Shotcreting operation in a tunnel leads to rebound loss of concrete up to 40% and the possibily of washout through the oozed water is very high. How can this be resolved?
A5. The same can be resolved by using DURASHOT P/L in wet as well as dry process.
Note- Alkali containing accelerators may have strength loss to the extent of 30%. In such cases by using alkali free accelerators i.e. DURASHOT LAF is strongly recommended where strength fall would be minimum.
Q6. Nowadays mixing water in most of the projects contains high chloride levels that may lead to corrosion of reinforcement of concrete over a period of time. Do you have any material to counteract this hazard?
A6. According to an European analysis, Corrosion is the biggest deterioration mechanism of a structure leading to crores of rupees wasted in the repair and rehabilitation annually. To counteract this problem, we have DURACOROBIT 60 that can be used at the rate of 0.7L per m3 of concrete which neutralises the effect of chloride.
Q7. Sometimes corrosion of reinforcement takes place due to reduction of alkalinity in a hardened concrete. Can we arrest the phenomenon of further corrosion?
A7. Yes we have a pH enhancer like DURALISER which can be injected to increase the pH levels and maintain the alkalinity of concrete. As a result corrosion levels can be checked.
Q1. How can porosity/honeycombing of concrete structure be reduced to a maximum extent?
A1. This can be done in 2 ways:
The cement milk must be admixed with DURAEV (Non shrink polymeric grouting compound). This slurry must then be introduced into the structure through grout pump.
Also ready to use grout like DURAGROUT E1 (only the required quantity of water needs to be added) can be injected.
Q2. How can holding down bolts be grouted/ anchored in the foundation?
A2. This can be done by pouring DURAGROUT GP in the holding down bolt pocket.
Q3. How can base plate be grouted so that it is perfectly leveled for the subsequent erection of machine?
A3. This can be done by forming a hydrostatic head pocket through which fluid DURAGROUT GP can be poured to complete the base plate grouting.
Tiling Related FAQS
Q4. It is observed that tiles on bathroom/ kitchen walls fall off and water seeps in through the
joints of tiles. As a result, the other side of the wall surface gets damaged due to dampness/ efflorescence. What is the solution?
A4. The tile should be fixed with DURAXY 1P/2P and the joints should be filled with DURATILOFIL. The tiles fall due to shrinkage or due to expansion of air entrapped between the tile and the wall.
Flooring FAQS
Q5. Sometimes dust accumulates on the factory floor due to release of lime.
How can such a problem be resolved?
A5. Such a problem can be solved using floor sealer DURAFLORSIL/DURAFLORHARD.
Q6. It is seen that the floor surface in a huge factory area is weak due to excessive
presence of water during the laying of fresh concrete. As a result, concrete surface develops poor
strength and is not waterproof which results in scouring. What solution does DURA have?
A6. In such a situation DURAHARD can be used which makes the surface highly impermeable and abrasion resistant.
Joint Sealants Related FAQS
Q7. How can expansion/ contraction joints be treated?
A7. Our polysulphide compound viz., DURASIL GPS which is non sag and gungrade can be applied on vertical as well as horizontal surfaces.
However DURASIL PPS can be applied on only horizontal surfaces like airport runways, etc.
Q8. Often window and door joints get cracked due to expansion/ movement between two elements.
How can this be resolved?
A8. This can be solved by using DURACRYL MP, joint sealing compound. It can be used for filling gaps and joints in concrete, doors, windows, etc.
Q1. Sometimes deep cracks appear on the concrete surface and in some cases spalling is observed. How can this be resolved?
A1. Cracked concrete/ delaminated concrete should be cut back upto sound concrete surface and sometimes below the reinforcement where huge corrosion products may be formed. This needs total cleaning before application of our R&R system. Sometimes sand blasting as a cleaning method may be adopted to remove rust/ loose particles from steel surface. Now once the surface has been prepared, the surface treatment can be provided in 3 ways:
The prepared surface must be coated with DURARUSTOBIT to prevent further corrosion. This should be followed by filling the surrounding area with mass-in-fill (Mass-in-fill refers to Cement: Sand: DURAKRIT mortar mixed in the ratio 1: 2.75: 0.5 followed by adding requisite amount of water).
The prepared surface must be coated with DURARUSTOBIT as above followed by application of DURAXY primer. Then the surrounding area of the concrete should be filled with DURAXY RM (2 pack system).
Another alternative is to treat the steel rod with DURAKRIT: cement slurry in the ratio 1:2. This can be followed by mass-in-fill as in (1)
Q2. Corrosion/ sulphate attack leads to reduction of the cross section of the concrete beams/ columns. As a result, the
strength along with the load bearing capacity of the structural element gets diminished. How can such a problem be addressed?
A2. In such a situation, necessary surface preparation in the form of cleaning must be adopted. Then jacketing with the help of DURAMICROKIT (Very high strength micro concrete powder) would solve the problem so that the necessary strength could be achieved.
Q3. Often surface cracks appear on concrete/ masonry surface due to expansion, heat cracks or excessive shrinkage.
What answer does Dura have?
A3. In such situations DURASILFIL 1P/2P can be used as it is a flexible and non shrink sealing material.
