SEALER / SURFACE HARDNER

The present invention relates to a novel product used as sealer or surface hardener.

Crystalline concrete waterproofing is becoming very popular. Different companies make different claims and in most of their products sodium silicate is used in some form, either as an aqueous solution or/and solid powder. As an aqueous solution, it is used directly on the concrete. In powder form it is formulated as a plaster or slurry along with some other chemicals and claims are made that the chemicals in the slurry penetrate the concrete and create a chemical reaction with the free lime that fills and blocks the pores of the concrete. Most of these companies claim that if the surface is cured for a longer time the crystals form deeper and deeper, thus waterproofing the substrate more effectively. In fact, some companies have even suggested curing this concrete or plaster for one year to complete the crystallization, which is obviously impractical.

PRIOR ART

US 6303234 discloses that Cellulosic materials, including dimension lumber, plywood, particle board, wafer board, paper, fabric and similar materials, were treated with sodium silicate (Na,sub.2 O.SiO.sub.2) in concentrations ranging from 400-0.04 g Na.sub.2 O.SiO.sub.2 /kg water and the surfaces of selected samples were further treated with silicon oxide (SiO or SiO.sub.2) applied in a molecular to micron layer thickness by vapor deposition. Tests were conducted to determine the effectiveness of these materials in terms of fire resistance, durability, duration of effectiveness and moisture resistance. For sodium silicate as a sole treatment, flame retardance was found to increase as the concentration of sodium silicate in solution increased. To overcome the disadvantages of sodium silicate, sodium silicate treated samples were further treated by the deposition of a molecular coating of silicon oxide by vapor deposition. Samples treated by this technique were found to be completely moisture resistance. The combined application of sodium silicate and silicon oxide was found to provide a fire retardant product that is moisture resistant and decomposition resistant and, therefore, effective for internal and external uses. Sodium silicate treated materials, where the sodium silicate is coated with a thin layer of silicon oxide does appear to provide an effective fire retardant material, US 6248697 teaches compositions and methods useful in creating boreholes, tunnels and other excavations in unstable soils and earth formations, especially those composed partially or wholly of sand, gravel or other granular or permeable material. The fluids include a polymer, and a soluble silicate ion source. The fluids of the invention, when used according to the methods of the invention, have unique dual functionality as excavating fluids and as earth-grouting or soil-hardening compositions.

The Applicant undertook an extensive study on sodium silicate related products and developed its own formulation known as Protekta Base. Protekta Base is produced by using silicates of sodium, zirconium, and calcium along with some lime, common salt and iron, nickel and copper derivatives. This aqueous mixture of silicates was further processed and it was found that its properties change if treated with polysaccharide-based surfactants, and its penetration and properties further change with the addition of ICI 3565, non-ionic surfactant alcohol ethoxylate.

All the sodium silicate based mixtures claim reduction in the permeability of concrete. The mode of action of these chemical admixtures is descried by different authors, but Tech-Dry's Protekta Base is unique and can be used for a variety of purposes. It is actually not just sodium silicate but a formulation of the products described above, making it multi-functional waterproofing product.

Protekta Base is a viscous liquid consisting of silicates and special biochemical proprietary chemicals. This product is used as a penetrating sealer/surface hardener on concrete to improve its resistance to the ingress of liquid water and contaminants.

Protekta Base is a non-toxic, environmentally safe, masonry penetrating, hardening and waterproofing treatment for concrete flooring.

Chemically, Protekta Base increases concrete strength by replacing soluble lime content with calcium silicate hydrate. By this process, the surface is rendered less permeable by moisture, reducing problematic alkalinity, and increasing the density of the concrete. Also, chemical resistance is improved by making the surface less porous.

After spraying this product one should use a 3-day watering process (spraying water three times, at 24 hour intervals). The product penetrates the concrete surface and reacts with the composition of the concrete internally, forming a sub-surface barrier, filling and waterproofing pores, capillaries and larger cracks against the ingress of water and contaminants. It reacts with free calcium and water to form a non-water soluble Calcium Silicate Hydrate gel complex in pore capillaries and cracks.

Uses:

• Permanently seals cracks up to 2.00 mm
• Reseals future hairline cracking
• Reduces chloride diffusion coefficient by 89%
• Increases surface hardness from 6 to 8 on Moh's scale
• Allows 70% moisture vapour permeability
• Suitable for tanking application (positive hydrostatic pressure)
• Non-toxic-certified suitability for potable water
• Use in crystallization products as grout in basements

• Serves as an excellent curing compound. It Can also be sprayed on green concrete without curing with water.

Application
• Protekta Base must be applied to a clean, dry, dust-free concrete surface, at least 28 days old. Plastered surfaces may be treated after 7 days.

• Any materials that retard penetration should be removed.

• Where segregation or voids are apparent, chip out, spray with Protekta Base, then make good with cementitious materials.

• Good concrete practice should be followed such as adequate curing,
compaction, and vibration.

• Old or carbonated concrete requires Protekta Guard treatment to reinstate free calcium,

• Do not apply where ambient temperatures are above +40oC.

• Coverage: 30-50 sq ft / litre

Application Method:

• Locate all cracks and spray with solution ensuring they are flooded with product.

• Protekta Base can be diluted with ordinary water and sprayed 3-4 times to increase penetration.

• Apply the solution to the remaining area; normal dosage 30-50 sq ft / litre

• When surface becomes touch dry (usually from 2-6 hours depending on wind conditions and ambient temperature), flood spray the treated areas with water.

• On day two, 24 hours later, water again.

• On day three, 24 hours later, water again.

• It is advisable after the third watering, to pond the area for a minimum of 12 hours to check leakage.

Technical Data:

Non-toxic

Biodegradable

Non-volatile solids : 27.7%

Non -hazardous chemical : Sodium Silicate (modified), silicates of zirconium,
potassium etc.,

pH : 117

After application to building materials, soluble metal silicate such as sodium silicate and other biochemically modified silicate can form silanols in the presence of atmospheric carbon dioxide or when the pH is reduced. Then the silicate silanol can condense to inorganic polysiloxane and at the same time can bond to the masonry substrate in the masonry capillaries. The soluble sodium silicate reactions are shown in figure 1.

Generally speaking, soluble sodium silicates cannot impart water repellent effects to the substrate by impregnation because there are no organic hydrophobic groups introduced to the masonry substrate. However, it is still claimed by previous workers 2, 68,69 that the impregnation of masonry materials achieves water resistance with soluble sodium silicate solution. The improved water resistance of masonry substrates is only due to the reduced permeability of the substrate by the silicate polymer in the capillaries and not due to any hydrophobic effect. In the case of treating concrete, a significant reduction in the permeability of substrates due to silicate solution impregnation may be achieved if the concrete is very fresh and repeated impregnations are carried out to give a filling of all the masonry capillaries 68'69, According to Vail 68, it is sufficient to seal the capillaries by saturating the concrete with the silicate solution on three successive days. If the concrete is fresh enough to contain some free calcium hydroxide, a satisfactory reaction may be obtained with a 10% solution of sodium silicate.

This product has multipurpose uses and has been used for Roads & Traffic Authority Bridges Deck Etc.,

The damaged asphalt was removed exposing the old structural concrete. After the application was complete, a new asphalt topping was installed over the Protekta Base treatment. There are two critical performance features of Protekta Base in this type of application. Firstly, the asphalt topping will still be able to gain full bond to the treated structural concrete. And secondly the temperature of up to 160°C during installation of the asphalt does not affect in the performance of Protekta Base.

The Applicant have undertaken extensive studies on the subject. Besides its usage on almost all substrates, the following would be worth mentioning.

Consolidation of mud bricks by Protekta Base impregnation

Test results conducted by totally immersing the mud brick substrates in water in a water bath showed that the untreated portion of the substrate deteriorated within 2 hours of immersion whilst the treated portion was able to stand in the water for more than 4 weeks. The consolidation effect of the substrate treated with the silicate is attributed to the adsorbed silicate gel (inorganic polymer) which is formed in the capillaries by cross-linking with the substrate.

The Applicant has also found a unique effect of Protekta Base in that it enhances the water repellency of the substrate treated with silane/siloxane emulsion. The water absorption value can be significantly further reduced by pre-impregnating the substrate with Protekta Base, when compared to that of the substrate without Protekta Base pre-treatment. As discussed previously, the water repellent effect is developed by organic silicone, which forms a hydrophobic thin film in the substrate capillaries. However, the water repellent effect may vary according to the final structure of the adsorbed silicone in the capillaries. One must assume that a polysiloxane thin film with higher molecular weight and fully crosslinked structure can impart a better water repellency to the substrate than that of a mono-molecular absorption of the base silicone.

After application to building materials, Protekta Base can form silanols in the presence of atmospheric carbon dioxide; or when the pH is reduced then the silicate / silanol can condense to inorganic polysiloxane and at the same time can bond to the concrete substrate in the concrete capillaries.

Roads, bridge decks, etc.

The damaged asphalt was removed exposing the old structural concrete. After the application was complete, a new asphalt topping was installed over the Protekta Base treatment. There are two critical performance features of Protekta Base in this type of application. Firstly, the asphalt topping will still be able to gain full bond to the treated structural concrete and secondly, it improves the CBR of the soil.

Protection of bitumen roads

Protekta Base can play a very key role in the maintenance of bitumen roads. It is very well known that bitumen, if left unprotected, degrades under ultraviolet light radiation resulting in delamination and cracking. Blister formation is also very common because of expansion and contraction on account of variable temperature.

For the longevity of bitumen asphalt roads, it is necessary to create a hydrophobic layer beneath the asphalt coating. Bitumen is normally applied at high temperatures and it is very difficult to find a waterproofing application that can withstand these temperatures. Protekta Base is unique in this matter, in that it can withstand more that 200°C.

Protekta Base is an excellent product for:

1. Reducing porosity
2. Consolidating and stabilizing of soil
3. Eventually improving the CBR value

Reducing porosity

Protekta Base is a waterbased impregnant and not a surface coating, admixture, crystal growth, or, a water repellent It is a specially made product, which is sprayed on cured concrete. The superiority of this Protekta Base is that it has been biologically modified and its effectiveness and penetration has increased several fold.

Consolidating and stabilizing of soil

The Novel Product permanently alters the soil, allowing maximum compaction and preventing the re-absorption of water. It thus increases the shear strength and load bearing capacity of the layer.

The product by its chemical composition, activate the ions H+ and (OH)', ionizing the water which then vigorously exchanges its electrical charges with the soil particles forcing the water to break its electrochemical bond with the soil particles to become free water which then drains from the soil through gravity or evaporation.

The novel product is specially formulated for the unique soil conditions of those regions of the world where there is a problem of monsoon rains. Roads built each year are virtually destroyed during the monsoon season. This makes transportation and commerce very difficult and unnecessary expenditure is needed on repair.

ENVIRONMENTALLY FRIENDLY

Protekta Base has no negative impact on the environment and is safe to handle. It is non-toxic, non-hazardous and water based. Where dust comes from: Fugitive dust consists of subgrade soil that has worked its way up through the aggregate and/or fine particles (fines) in the aggregate mix. Fines act as cement or stabilizer for the mix and help prevent potholes, washboards, and washouts.

APPLICATION AS DUST PALLIATIVE

• Streets and roads in rural and residential areas
• Construction sites
• Mine dumps and workings
• Temporary bypasses

• Parking areas

• Other dust sensitive areas

Protekta Base can be impregnated into the concrete and its properties studied by using Electron Spin Resonance (ESR), which shows that it reduces the permeability of the concrete by 65%. The major role is played by surfactants. Therefore based on the factors stated above, it was decided by the Tech-Dry group to undertake further studies on this formulation.

The consolidation and water repellent effect of the earth substrates treated with Protekta Base followed by impregnation with water-based silane/siloxane emulsion was found to be significant. The consolidation of the earth by soluble sodium silicate impregnation is attributed to the silicate gel (polymer) formed by crosslinking with the surface through siloxane bonds to improve the adhesion between earth particles. The water repellent effect of the substrate is due to the formation of a hydrophobic organic polysiloxane thin film which bonds to the substrate. This polysiloxane increases the contact angle of water on the capillary wall surface and greatly reduces the water absorption through capillary depression. The pre-impregnation with soluble sodium silicate greatly enhances the water repellent effect of the treated substrate by improving the molecular weight and the crosslinked structure of the polysiloxane in the capillaries through i) increasing the pH of the substrate, ii) reducing the surface area of the capillary wall and iii) increasing the surface chemical functionality.

This product is supplied as a powder known along with Base. It is based on cement/sand/lime/magnesium salt/ calcium salt and sodium salt along with some surfactant and impregnants. This powder is converted into slurry added with approximate amount of water and a coat of 2 mm is applied subsequently this coating pushes the Base into the capillaries where it forms Calcium Silicate Hydrate (C.S.H) with calcium ions.

The novel product relies on free lime in concrete to chemically react and pore block. It generally takes a leaking crack some years to become totally leached of lime. When undertaking remedial repairs to long term leaks, particularly in swimming pools where chemicals accelerate the loss of lime, a pretreatment of food quality, Calcium Acetate should be flooded into the known leaking cracks. The Calcium Acetate, which reacts in the same way as lime, is supplied to Approved Applicators for his purpose. The normal procedure is to flood spray the suspect leaking cracks the afternoon before the novel product treatment allowing sufficient moisture to evaporate overnight. The crack edges are scrubbed with water to remove excess acetate, otherwise a white stain will result. The water will assist in causing the acetate to soak all the way through the crack. The next day the novel product can be applied to the crack, allowed to dry and then watered normally.
In old building where calcium ions is not available it is necessary to spray formulated calcium acetate. The present novel product can also be used directly sprayed on concrete where used as concrete curing compound.

According to the invention a process for preparing sealer/surface hardner comprises:

a) Taking 10 to 40% alkaline earth metals in a stainless steel open vessel fitted with a homogenizer,

b) Adding equal amount of water while stirring the vessel constantly to obtain a liquefied solution,

c) Stirring with a homogenizer at 2800 rpm to get a homogeneous solution,

d) Adding 2 to 15% of organic additive to this homogeneous solution,

e) Stirring the solution for at least one hour to get a homogeneous solution acting as a sealer/surface harder.

According to the invention a process for preparing sealer/surface hardner comprises:

a) Taking 15 to 35% w/v lime stone powder in a stainless steel open vessel fitted with a homogenizer,

b) Adding 30 to 60% w/v flurides,

c) Adding 20 to 35% w/v silicate,

d) Adding 10 to 25% w/v Sodium Bentonate,

e) Adding 2 to 8% w/v of magnesium and/or sodium sulphate or a mixture thereof,

0 Adding 9 to 19% w/v magnesium and/or calcium chloride or a mixture thereof,

g) Adding 40 to 80% w/v quartz sand,

h) Adding 40 to 80% w/v quartz sand,

i) Adding 0.2 to 20% spray dried polymers,

Stirring for one hour to get a homogeneous solution acting as a sealer/surface hardner
According to the other embodiment of the invention, a sealer/surface hardner comprises 10 to 40% alkaline earth metal silicates like sodium silicate, potassium silicate, magnesium silicate, zirconium silicate dissolved in an equal amount of water ,2 to 15% of alcohol ethoxylates and 5 to 15% of organic additives; wherein the ingredients are mixed in a homogenizer stirring at 2800 rpm for a period of 45-65 minutes to obtain a homogeneous composition to crystallization.

According to the other embodiment of the invention, a sealer/surface hardner for crystallization comprises15 to 35% of Lime Stone Powder, Flurides like magnesium,sodium,20 to 35% silicate like sodium, zirconium, calcium,10 to 25% Sodium Bentonate,2 to 8% of magnesium or sodium sulphate,9 to 19% magnesium or calcium chloride,40 to 80% quartz sand,0.2 to 20% of spray dried polymers ;wherein the ingredients are mixed in a homogenizer at 2800 rpm for a period of 45 to 65 minutes to obtain a homogeneous composition allowing the composition to crystallization.

According to the invention a process for preparing sealer/surface hardner wherein the penetrant is alcohol ethoxylates.

The invention is described with respect to the following examples without restricting the scope of the invention.

EXAMPLE -1
Take 50 Itr stainless steel open vessel fitted with a homogenizer with 2800 rpm speed. Take 10 to 40 % of alkaline earth metal silicates like sodium silicate, potassium silicate, magnesium silicate, zirconium silicate and to this solution add equal amount of water and stir constantly. Add 5 to 15 % of organic additive which works as penetrant and add 10 to 15 % of alcohol ethoxylates and stir for 1 hour. This product is used as crystallization product in the manner given above.

EXAMPLE – 2

Take 50 Itr stainless steel open vessel fitted with a homogenizer with 2800 rpm speed. Take 15 to 35 % of alkaline earth metal silicates like sodium silicate, potassium silicate, magnesium silicate, zirconium silicate and to this solution add equal amount of water and stir constantly. Add 2 to 15 % of alcohol ethoxylates which work as penetrant and stir for 1 hour. This product is used as crystallization product in the manner given above.

EXAMPLE – 3

Take 50 Itr stainless steel open vessel fitted with a homogenizer with 2800 rpm speed. Take 15 to 35 % of Lime Stone Powder, 30 to 60 % Fluride like Magnesium, Sodium, 20 to 35% Silicate like Sodium, Zerconium or Calcium , 10 to 25% Sodium Bentonate, 2 to 8% of Magnesiun or Sodium Sulphate, 9 to 19% Magnecium or Calcium Chloride, 40 to 80% Quartz Sand, 0.2 to 20% of Spary Dried Polymers and stir for 1 hour. Product called as Protex. This product is used as crystallization product in the manner given above.

Advantages:

• Improved road standards:
dust free road surface ensures safer and more comfortable driving

• Improved quality of life: less dust

• Cost-effectiveness:

requires the minimum construction and road preparation efforts to create a positive life cycle : cost ratio

• Easy application:
spray with standard spray equipment; specialized equipment not necessary

• Easy and affordable maintenance:
normal maintenance of the surface can be achieved with the minimum expertise and standard equipment; rejuvenation can be done as and when required

• Quick drying:
penetrates rapidly; the road can be opened to traffic immediately
Properties

• Porosity reduction of concrete by 65%
• Consolidation of surface
• Consolidation of soil for road. CBR improved
• Seals cracks, particularly hairline cracks
• Dust palliative
• Can be used by spraying on the surface of roads before laying hot bitumen. Stable at 160°C
• Enhances the properties of repellents if sprayed before repellent is applied.
• Can be used in place repair of roads
• A good grouting aid with cement and other grouting products.

We claim:

1. A process for preparing sealer/surface hardner comprising the following steps:

f) Taking 10 to 40% alkaline earth metals in a stainless steel open vessel fitted with a homogenizer,

g) Adding equal amount of water while stirring the vessel constantly to obtain a liquefied solution,

h) Stirring with a homogenizer at 2800 rpm to get a homogeneous solution,

i) Adding 2 to 15% of organic additive to this homogeneous solution,

j) Stirring the solution for atleast one hour to get a homogeneous solution
acting as a sealer/surface hardner.

2. A process for preparing sealer/surface hardner comprising the following steps:

a) Taking 15 to 35% w/v lime stone powder in a stainless steel open vessel fitted with a homogenizer,

b) Adding 30 to 60% w/v flurides,

c) Adding 20 to 35% w/v silicate,

d) Adding 10 to 25% w/v Sodium Bentonate,

e) Adding 2 to 8% w/v of magnesium and/or sodium sulphate or a mixture thereof,

f) Adding 9 to 19% w/v magnesium and/or calcium chloride or a mixture thereof,

g) Adding 40 to 80% w/v quartz sand,

h) Adding 0.2 to 20% spray dried polymers,

i) Stirring for one hour to get a homogeneous solution acting as a sealer/surface hardner.

3. A process for preparing sealer/surface hardner wherein the earth metal silicates are sodium silicate, potassium silicate, magnesium silicate, zirconium silicate or a mixture thereof.

4. A process for preparing sealer/surface hardner wherein the penetrant is alcoholethoxylates.

5. A process for preparing sealer/surface hardner wherein the penetrant is organic additive.

6. A process for preparing sealer/surface hardner wherein flurides are sodium fluride and magnesium fluride or a mixture thereof,

7. A sealer/surface hardner comprising 10 to 40% alkaline earth metal silicates like sodium silicate, potassium silicate, magnesium silicate, zirconium silicate dissolved in an equal amount of water ,2 to 15% of alcohol ethoxylates and 5 to 15% of organic additives; wherein the ingredients are mixed in a homogenizer stirring at 2800 rpm for a period of 45-65 minutes to obtain a homogeneous composition to crystallization.

8. A sealer/surface hardner for crystallization comprising 15 to 35% of Lime Stone Powder, Flurides like magnesium,sodium,20 to 35% silicate like sodium, zirconium, calcium,10 to 25% Sodium Bentonate,2 to 8% of magnesium or sodium sulphate,9 to 19% magnesium or calcium chloride,40 to 80% quartz sand,0.2 to 20% of spray dried polymers ;wherein the ingredients are mixed in a homogenizer at 2800 rpm for a period of 45 to 65 minutes to obtain a homogeneous composition allowing the composition to crystallization.

9. A process for preparing sealer/surface hardner substantially as hereinbefore described with reference to the accompanying examples.

10. A sealer/surface hardner substantially as hereinbefore described with reference to the accompanying examples.