Вопросы | "TOKAR" LLC


Can the d-5 admixture help solve the problem of a leaking roof in the house?

Yes, it will help. You should pour a layer of concrete the existing floor with reinforcement mesh using the D-5 admixture (3% of the weight of cement).

The thickness of the concrete slab should not be less than 20 cm. It is not recommended to use cement-sand grout as the only layer of waterproofing in flat roofs, if reinforced concrete structures are made without it. In thin cement-sand grouts located under the open air permanent changes of temperature (day-night, winter-summer) lead to through microcracks.

This leads to damage in their waterproofing. In such cases it is necessary to provide additional reliable waterproofing. It is recommended to use a flat roof slab from monolithic reinforced concrete with the D-5 admixture at least 200 mm thick.

The slab will have its own high waterproofness, so the microcracks will not develop along the entire thickness of the slab, and no additional waterproofing will be required.

Is it possible to use the d-5 admixture for prestressed reinforced concrete structures?

Yes, it is possible. This is confirmed by the Certificate of Conformity of the D-5 admixture, as well as by the experts’ report of the Concrete and Reinforced Concrete Research Institute  titled after A. Gvozdev. Many concrete admixtures contain chemical, aggressive components. Hardening accelerators often contain chlorine. In pre-stressed reinforced concrete structures they cause corrosion of reinforcement. Therefore, that kind of admixtures could be used not everywhere. The D-5 admixture has no restrictions, as it is based on mineral, natural raw materials.    Moreover, the D-5 admixture is recommended for use in pre-stressed floor slab manufacturing technology as it prevents corrosion of reinforcement in concrete. As an example we can mention the plant of reinforced concrete structures in Armavir, with which we have been cooperating since 2010. You can see the feedback on our website.

Is it possible to exclude the “steaming” process when making prestressed floor slabs?

Using the D-5 admixture (3% of the cement weight), it is possible to replace the “steaming” process with normal heating at 30 – 50 < sup > 0 </sup > C, i.e. to replace the steaming process with fan heater with automatic temperature control. To avoid loss of moisture from concrete, the slabs must be covered with film.

Is it possible to eliminate continuous concreting with the d-5 admixture?

Yes, it is possible. “Cold” joints in concretes with the  D-5 admixture do not leak, even if the break in concreting is 3-4 weeks. You just need to take several simple steps (see our website tokard5.ru, section “Recommendations to use  the D-5 admixture”).

Is the D-5 an expansion admixture?

No, the D-5 is not an expansion admixture. The concrete shrinkage with it is significantly less than without the D-5 admixture. Therefore, there are almost no shrinkage cracks in concretes with the D-5. Expansion admixtures can lead to self-destruction of concrete. With the D-5 admixture such risks are completely excluded.

Does the temperature of the concrete rise when the d-5 is added and mixed?

No, since there are no components in the D-5 admixture that raise the temperature of the concrete.

What is the d-5 admixture proportion for commercial concrete and concrete goods?

For both commercial concrete and concrete goods the recommended proportion is 2-3% of the weight of cement. The higher the proportion, the better the effect. The amount of the admixture in each particular case is selected individually depending on the required properties: strength, fluidity, water resistance W, frost resistance F, and others.

How does the d-5 admixture change fluidity of the concrete?

Fluidity of the concrete increases from 1-4 cm to 21-25 cm.

Can the D-5 admixture be used for vibropressed hard concrete products?

Yes, it is possible. Pressed facing bricks of high quality with the D-5 admixture on very hard mixtures have been produced in Vladikavkaz for several years.

How to get rid of wall saltpetre on finished products (street furniture made of concrete)?

First, check the cement. It is better to use non-neat cement such as or Portland cement  500 without admixture. Second, check the sand and crushed stone for limestone. It is preferable to use aggregates from dense rocks and without organic (sludge). Apply the D-5 admixture (3% of cement weight) and exclude all other admixtures and plasticizers. It binds free lime released during cement hydration. Free lime is the main reason for the appearance of salts.

The addition of D-5 admixture during the production of pressed bricks eliminates the problem of salts.

I produce gas silicate units. is it possible to increase strength while producing a gas silicate mixture and in finished products using the d-5 admixture?

Yes, it is possible if you use autoclave-free technology of gas silicate units production. With this technology cement-based mixtures are used, and the D-5 admixture shows here high efficiency. For maximum effect try first a maximum dosage of 3% of the cement weight while reducing the amount of water (until the desired mixture consistency is obtained). In the future it will be possible to adjust the proportion of the D-5 admixture and other components depending on the result obtained.

How does the d-5 admixture affect segregation and drainage?

The use of the D-5 admixture significantly reduces segregation and water separation of the concrete mixture by more than 2 times compared to the concrete mixture without it (in mixtures with equal fluidity).

How does the d-5 admixture react with different cements?

The D-5 admixture is universal. It shows its high efficiency in combination with almost all cements, even if they contain slags up to 20%.

How to use the d-5 admixture to produce waterproof concrete?

Before using the D-5 admixture  you should clearly understand that all its properties are interrelated. Using the D-5 admixture you will produce not only waterproof concrete, but also concrete with accelerated hardening process, with increased strength, with increased frost resistance, sulfate resistance, high-plastic, without stratification and water separation, with regulated air treatment, and with high preservation of concrete mixture, i.e. concrete will have all the properties, which are detailed in the section about the D-5 admixture.

The technology is very simple. You should add the dry D-5 admixture into concrete mixer simultaneously with sand or cement. Recommended dosage is about 2-3% of cement weight. All components of the concrete mixture are added into the concrete mixer as usual. Pay special attention to the fact that the amount of mixing water should be reduced by 20-30% compared to conventional concrete without admixtures. IT IS IMPORTANT NOT TO USE TOO MUCH WATER. The amount of water should be selected experimentally based on the desired fluidity of the mixture.

All other similar components and plasticizers should be excluded from the concrete if you use the D-5 admixture.

What if the basement of a house leaks and is filled with water during rain?

First of all, drain the basements using a depth pump. After that, it is necessary to dig a hole, about 1 m deep below the floor level of the basement and put a subsurface pump of sufficient power capable to pump water.

Then wash and clean the walls and floor of the basement from dirt and loose concrete. Reinforce the basement floor and walls with a mesh reinforcement designed to withstand water pressure from below to the basement bottom and from the side to the basement walls (it is necessary to know the basement depth and dimensions of the rooms in the basement). Reinforcement diameter is determined by calculation. A reinforcement cell is selected from 150х150 to 200х200 mm. The hole with the operating subsurface pump is also covered by a reinforcement mesh allowing subsequently to pull out the pump.
Make waterproof concrete using the D-5 admixture (3% of cement weight) and fill with such concrete a layer 15-20 cm thick on the basement floor (leave only the hole with operating pump). The concrete mixture must be vibrated while pouring. The walls of the basement are concreted to the height of maximum water rise plus 50-70 cm. The thickness of the concrete of the walls should be not less than 10 cm to ensure the possibility to vibrate the walls with deep vibrators.
It is important to ensure in accordance with our Recommendations that “cold” joints do not leak.

Wall forms can be removed after 2 days.
The required quantity of waterproof concrete with the D-5 admixture (at a proportion of 3% of cement weight) and standard fluidity (1-9 cm) should be prepared for walls stripping. The volume of concrete should be about 30% more than the volume of the hole in the basement floor. Turn off the water pump and pull the pump out of the hole. Immediately after that fill the hole with concrete compressing with a deep vibrator. After this, water resistance of the basement will be ensured for the whole life of the building

We built a swimmingpool using concrete without waterproofing. what should we do?

You should clean the concrete of dirt and dust, then wash it with clean water.

Then fix a reinforcing fabric by dowels. A wire is  about 1-2 mm thick, a cell is from 50х50 to 100х100 mm.

Make a waterproof  mixture using sand, cement and the D-5 admixture. For 1 portion you need: Portland cement  500 without admixture or Portland cement  500 with 20% admixture = 1 bag (50 kg); the D-5 admixture = 1 package (1 kg); medium sand = 7 buckets of 12 liters (120 kg) and water of about 20 liters. All components should be thoroughly mixed. Fill the D-5 admixture in the mixer after cement. It is recommended to pour water in 2 stages: first pour about half of the expected amount of water, until the required fluidity is obtained. It is important not to use too much water here! After all the components are added, the mixing time must be at least 3 minutes.

It is recommended to plaster walls in 2 stages: first the outline, then, after the first layer is fixed on the wall, the outline of the second layer and the trowel finish. The plaster layer on the walls must be not thicker than 2-3 cm. A mixture of medium and coarse sand in about equal proportions should be applied on the bottom. The bottom concrete should have minimal fluidity. The concrete must be compacted while laying. Put it in one layer to the required thickness at once. The layer should be from 3 to 5 cm thick.

The “cold” joints between the wall plaster and the bottom concrete must be cleaned with a metal brush to eliminate the film from laitance and baring of the concrete. After that the dust must be washed out with clean water. In this case, maximum adhesion and splicing of the fresh concrete with the previously laid and solidified concrete and high waterproofness of the “cold” joint will be ensured.

If the work is carried out in summer and under open air, it is necessary to prevent rapid evaporation of water from the plaster layer in order to avoid formation of cracks: pour water and cover walls and bottom with film. It is recommended to wet walls and bottoms 2 times a day (in the morning and in the evening) during the first 7 days. After 7 days of hardening under such conditions high waterproofness and strength of plaster layer with the D-5 admixture will be ensured. So it is possible to pour water into the pool to the full depth and check it for waterproofness.

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