Recommendations for use of the D-5 admixture | "TOKAR" LLC

Recommendations for use of the D-5 admixture


Before using the admixture at a precast reinforced concrete plant or at a mixing station it is necessary to make proportioning of concrete with the D-5 admixture under laboratory conditions in order to determine the optimal proportion of the admixture with those cements and aggregates used at a particular plant.


For each grade of concrete it is necessary to test one Control Concrete Mix without admixture (which is used in this production), and one Basic Concrete Mix with 3% D-5 admixture of cement weight.

Both mixes consist of the same materials, with the same dosage of the primary components (except water) and must be of equal slump. The Control and Basic mixes differ only in the presence/absence of the D-5 admixture and the amount of mixing water. In the Basic Concrete Mix (with the D-5 admixture) the amount of water should be reduced by 15-25% or more, as compared to the Control Concrete Mix, to get mixes with equal slump.


The D-5 admixture does not require any pre-mixing with water. When making concrete mixes the D-5 admixture is poured into a concrete mixer in powder form together with sand or cement. After pouring water the composition should be mixed for 30-120 seconds (depending on the mixer type and the required flowability of the concrete mix) and during this time the admixture will be distributed equally throughout the mix. When using gravity batch mixers, the mixing time is increased to 5 minutes or more.

Transportation, pumping and placing of concrete with the D-5 admixture into formwork should be done as usual. The difference is that the concrete mix with the D-5 admixture has a high water-retaining capacity, does not disintegrate, preserves its flowability for a longer period and is easier to pump. The concrete mix with the D-5 admixture is vibrated well.


Almost at all monolithic construction sites there is a problem of «cold» joints in places where breaks in concreting took place, i.e. when the previously laid concrete has already hardened and a ready-mixed concrete is laid upon. After hardening the place of «cold» joint becomes an artificial crack in the body of the concrete, as in this place concrete has lost its homogeneous texture and monolithic structure. Therefore, it is in these places that water will leak.

When using concretes with the D-5 admixture, the problem of «cold» joints is solved in the most reliable way: «cold» joints in concretes with the D-5 admixture do not leak.

To achieve this effect the following steps are required:

– in case of breaks in concreting, clean the surface of the previously laid concrete of cement crust in the place of the future joint, strip the structure of the concrete, wash off dust and fine particles and abundantly water the concrete;

– in case of breaks in concreting from a few days to several weeks, the place of the joint should be abundantly watered to clean dust, sawdust and all the dirt, and only after that a ready-mixed concrete may be poured. At the same time if concrete is laid using a concrete pump, it is necessary to ensure that the first portion of concrete (20-30 liters) is lubricated with oil, which is poured by the concrete pump operator, is drained away.

Under these conditions high adhesion and fusion at the molecular level between hardened and freshly laid concrete with the admixture D-5 will be provided and high waterproofing of «cold» technological joints will be achieved, even if the break in concreting is 30 days or more (both hardened and freshly laid concrete must contain the D-5 admixture). Thus, the effect of «self-healing» of through cracks in concretes with the D-5 admixture manifests itself.


For waterproof ceilings in flat roofs and terraces that do not require any additional waterproofing, a slab of flat roof or terrace should be made of monolithic reinforced concrete with thickness not less than 220 mm with the D-5 admixture at a dosage 3-4% of cement weight. Such floor slabs will have high waterproofing characteristics W16-W20 (reliable primary protection according to the State Standard 31384-2017). Microcracks will not develop all over the floor slab due to constant alternating temperature strains (day-night, winter-summer), hence no additional waterproofing is required. Additionally we recommend to protect concrete against solar radiation to avoid excessive drying up of concrete.

It is important to consider that in case of large-size floor slabs and polyline slabs, it is necessary to arrange contraction joints in places of breaks and every 6 meters. In such cases it is necessary to provide waterproofing of joints.

It is not allowed to use sand-cement screeds with the D-5 admixture as the only layer of waterproofing in flat roofs and open terraces, if the bearing reinforced concrete structures are made without the D-5 admixture.

In thin cement-sand screeds in the open air constant alternating temperature strains lead to through microcracks and waterproofness of screeds is damaged. In such cases it is necessary to provide additional waterproofing or initially to make the bearing structure of the floor slab of monolithic reinforced concrete with the D-5 admixture at a proportion of 3-4% from the weight of cement.


In extreme cases when it is not possible to manufacture concrete mix with the D-5 admixture at a plant, and it is necessary to add the D-5 admixture directly into the mixer with the ready-mixed concrete at a construction site, as an exception it is possible to use this method under the following conditions:

– first, it is necessary to order a concrete mix with low flowability (P1), since the D-5 admixture has a high plasticizing effect, and if it is added to the mixer with the ready-mixed concrete with P3-P4 flowability, the concrete mix will be disintegrated, which is unacceptable in construction;

– secondly, before applying such an extreme method of adding the D-5 admixture to concrete, it is necessary to test the method on one mixer. For this purpose it is necessary to know the amount of cement in the volume of concrete in the mixer. The required amount of the D-5 admixture is calculated at the rate of 2% of cement weight, this amount of the admixture is added into the mixer (no need to mix it with water beforehand!). The mixer should spin for 3-5 minutes at high RPM. After that the concrete mix is checked for flowability and homogeneity. If the concrete mix acquired the required flowability and homogeneity, it can be used at a proportion of 2% of the weight of cement. If the concrete mix is not plastic enough, it is necessary to increase the dosage of the D-5 admixture to 2.5-3% to obtain the required flowability of the concrete mix.

After exercising this technology on one mixer, it can be used for the whole volume of concrete, but it is necessary to supervise flowability of both primary mixes and ready-made mixes with the D-5 admixture in every mixer.

Reminder! This method can be used only in extreme cases and with constant qualified control over each mixer.

For orders and offers - fill out the form!