Grouting cement: grades, composition and fields of application

One of the varieties of Portland cement is grouting cement. This type of Portland cement can be used in the widest range for grouting. It occupies one of the most important places due to a good combination of technical and construction properties.

What kind of material is this and how does it differ from the usual cement mortar? About it - further.

Specific features

What makes cement cement different from Portland cement is the composition: for its manufacture, certain additives are added to the ground clinker base with gypsum.

Different types of mixtures are made for oil and gas wells, which are divided into the following subspecies:

1. Hygroscopic. To obtain the material, a triethanolamine hydrophobizer is introduced into the dry mass.
2. Weighted. For the manufacture of cement clinker is mixed with gypsum and weighting additives. Such may be iron ore in the form of heavy tails, hematites, magnetites.
3. Sandy. To obtain the material of this subspecies, quartz sand with gypsum is added to the mixture. The number of components should not be more than 50% for "hot" wells and less than 20% for "cold".
4. Salt resistant. It is used where salts in groundwater are highly concentrated. This leads to corrosion, but the addition of fine silica sand eliminates this disadvantage.

The technical characteristics of each type depend on the proportions and properties of the components. These may include quartz sand, minerals, limestone, and slag.

Application technology

Since cement must not be poured manually, but pumped, the mass is made sufficiently liquid. To do this, add 1 part of water to 2 parts of the dry mixture. The resulting mass is called pulp. If the temperature is high, the pulp can harden in 1.5-10 hours. The higher the temperature, the faster cement cement will set. Application in cold wells (or if the mass is used in waterproofing works on the construction of buildings in the cold season) leads to the fact that the hardening process will begin in 2-3 hours and end in 20-22 hours. Salt-resistant cement hardens for the longest time.

The bending strength index two days after complete solidification is as follows:

1. If there is no heating, approximately 62 kg / cm.
2. If the temperature is stably high - 27 kg / cm.

But this is only if high-quality cement is used. How to check its quality? There is a very simple and reliable way - to test through a sieve. To do this, carefully sieve a little dry powder through a sieve. If parts of the initial volume are left in the sieve, the material is of high quality. You can check by eye, but only those who have extensive experience working with grouting cement can do this. Otherwise, you have to trust the seller. But at the same time, it is worth paying attention to the composition of the dry mixture - the amount of gypsum should not be more than 3.5%.

Specifications

The main features of the material are the following indicators:

1. High curing speed. But at the same time, the mobility of the mixture mixed with water remains for a long time.
2. Water resistance. The solution may harden even under water.
3. Combination with different fillers. Moreover, it can also be surfaces having a physicochemical nature, including steel.
4. Regardless of the environmental conditions, the hardened mixture retains its strength and integrity for a long time.

Classification Features

Grouting cement is of several types. All of them differ in different parameters. So, according to the composition of substances, the material is of the following types:

• I - no additives;
• II - with mineral supplements;
• III - with special additives. They are used to adjust the density of the solution.

Material of type III is weighted (Ut) and lightweight (Ob). In addition, each type of material is divided into types intended for use at normal (25-50), low (15-24), moderate (51-100) or elevated (101-150) temperatures.

Legend

To determine the grade of material, special marking is used:

1. Cement grouting - PTsT.
2. Sulfate resistance - SS.
3. The average density.
4. The most admissible temperature when performing work.
5. Plasticization or hydrophobization. Designated as Pl, Gf.
6. Standard rate.

Example: PCT-I-SS-100. The designation carries the following information: the material is cement Portland cement, which does not contain additives, is sulfate-resistant. Designed for use at temperatures from 51 to 100 degrees.

PCT-III-UT1-100. This is a grouting type of Portland cement, lightweight type with a density of 2.1 g / cm ³ . You can work with the material at a moderate temperature.

PTsT-III-Ob5-50 - cement grouting. It is a lightweight type. It has a density of 1.5 g / cm3 ^. It is allowed to work at normal temperatures.

Quality checking

This material is intended to create well waterproofing, but cement slurry is often used in construction during the construction of some residential or industrial facilities. But in order for the material to be able to fulfill its intended task, to ensure the tightness and reliability of the created structure, and at the same time be environmentally friendly, it must be of high quality, and the composition appropriate to the complexity and characteristics of the tasks. For this, the created mixtures are tested.

There are different methods for testing cement grouting, which is what specialized laboratories do. They determine the following indicators:

1. Density (specific gravity).
2. Rheological properties.
3. Thickening time.
4. Water separation.
5. Filtration losses.
6. Tensile strength.
7. Resistance to ultrasound.
8. Permeability of the hardened material by liquids, gas, air.