RU2305149C2 - Mix to create lower layers of road pavement base - Google Patents

Abstract

FIELD: motor road building and repair, particularly to create lower pavement base layers and upper ground bed layers.

SUBSTANCE: mix comprises inorganic binding agent, namely cement, and surfactant. The surfactant is cationic surface active agent. The components are taken in the following amounts (% by weight): soil - 77.89-83.91, cement - 4-6, water - 12-16, surfactant - 0.09-0.11.

EFFECT: extended range of surfactants used for complex consolidation of ground to be utilized for motor road building and repair, increased road service life due to improved water- and frost-resistance of soil-cement used for road building.

2 cl, 2 tbl, 1 com

Description

The invention relates to the construction and repair of roads and can be used for the device of the lower layers of the base of the pavement.

The bottom layer of the base should provide high performance: the necessary strength, water and frost resistance, which is an indispensable condition for the longevity of roads.

Significant distribution has received a comprehensive method of strengthening soils using surface-active substances (surfactants) and cement as a binder. Surfactant treatment allows to increase the elastic modulus and strength characteristics of clay soil. At the same time, the water resistance and frost resistance of the soil increases, and the optimum humidity decreases. A characteristic feature of the method is the use of surfactant solutions of very low concentration. This circumstance makes it possible to obtain a significant economic effect in the construction of road bases (see V.M. Bezruk. Soil Strengthening. M: Transport, 1965).

One of the modern surfactants is “Renolith”, “Status”.

Closest to the proposed invention in technical essence and the achieved result is a mixture for the device of the lower layers of the base of the pavement, which is described in the book of V.M. Bezruk “Strengthening soils in road and airdrome construction”, M .: Transport, 1971, pp. 112-124 (in particular, p.118-119 and Fig. 28.29). The mixture includes oil with surfactants in it that have hydrophobic properties, cement, soil (sand) and water.

The composition of the cement-soil mixture with the addition of oil:

- 83-65% soil;

- 6-12% of cement;

- 1-5% oil;

- 10-18% water.

The disadvantage of the mixture is the insufficient strength of the cement soil, when testing samples for frost resistance, soil swelling is observed, which is associated with high porosity and high water absorption, which in some cases reaches 20% or more. The mixture contains a large percentage of binder (cement), which significantly increases the cost of the mixture.

The essence of the invention lies in the fact that the mixture for the device of the lower layers of the base of pavement, including an inorganic binder - cement and surfactant, as a surfactant use a cationic surfactant DON-52KP in the following ratio of components,%:

- Soil 77.89-83.91 - Cement 4-6 - water 12-16 - DON-52KP 0.09-0.11

The use of cement in the mineral part of the cement-soil mixture can improve the compressive strength.

DON-52 KP (cationic reagent) was used as a surfactant in a cement-soil mixture.

Introduction surfactant DON-52 KP allows you to directionally control capillary water absorption in soils. When interacting with cement, due to the alkaline environment of the surfactant, new structural bonds are created that contribute to an increase in the flexural strength, which is important for the lower layers of pavement.

Characterization of raw materials

1. The ground.

For complex strengthening, light dusty loam with a ductility number of 11.03 was used (the yield strength of the soil is 20.72%, the rolling limit is 9.69%). The maximum soil density at an optimum moisture content of 11.0% was 2.22 g / cm ³ , the skeleton density for these conditions corresponded to a value of 2.01 g / cm ³ .

2. Cement.

Used brand 500.

3. surfactant

Used cationic reagent for road construction "DON-52 KP" manufactured by JSC "NIIPAV", Volgodonsk. Specifications TU 2482-002-04706205-01.

The cationic reagent "DON-52 KP" is a composition, the active basis of which are derivatives of higher aliphatic amines in an organic solvent. "DON-52 KP" is a brown liquid with a weak specific odor, with pH = 7 ± 1, with a viscosity of 7-12 mm ² / s at 20 ° C and a density of 0.83-0.86 g / cm ³ .

4. Water - technical.

Example. For experimental verification of the claimed composition were prepared 5 options for compositions of cement-soil mixtures. As starting materials, the above materials were used.

The preparation of cement-soil mixture with the addition of surfactants was carried out in the following order. Cement in the amount of 4-6% was added to the soil sample of 77.89-83.91%, the mass was mixed until uniform. DON-52KP in the amount of 0.09-0.11% was dissolved in water, the amount of water is determined depending on the optimum soil moisture and is 12-14%. An aqueous solution with DON-52KP dissolved in it was introduced into the cement ground, the mass was mixed until homogeneous.

From the cement-soil mixture obtained, stabilized by a stabilizer, 5 × 5 cm cylindrical molds were molded.

Samples after 28 days of storage in a humid environment were placed in water at 1/3 of the height for a day and completely on the second day. After two days of water saturation, the samples were weighed and tested for tensile strength in compression and bending. The test results comply with the requirements of GOST 23558-94, CH 25-74. The results of comparative tests are shown in table 2.

Table 1
Organoleptic and physico-chemical indicators of DON-52KP The name of indicators TU norm Test method 1. Appearance Light to brown homogeneous liquid product Visually 2. Mass fraction of the active part,% not less 37 According to clause 4.2. real TU 3. Viscosity, cCm, at 20 ° C 7-12 According to GOST 33 4. Density, g / cm ³ , at 20 ° C 0.82-0.85 According to GOST 18995.1 5. The pour point, ° C, not higher Minus 5 According to GOST 20287

table 2
The composition of the cement-soil mixture, reinforced surfactant DON-52KP, and their physical and mechanical properties №№ Mixture composition Property metrics Soil,% Cationic additive DON-52KP,% Oil,% Water% Cement,% Water saturation,% Frost coefficient The compressive strength of water-saturated samples, MPa one 86.92 0.08 - 10 3 1.15 0.70 3,5 2 83.91 0.09 - 12 four 1.15 0.68 3,7 3 80.9 0.10 - fourteen 5 1.16 0.68 4,5 four 77.89 0.11 - 16 6 1,2 0.66 4.8 5 74.88 0.12 - eighteen 7 1,2 0.65 5 Prototype 75 - 3 fourteen 8 1.7 1,1 18 kg / cm ² = 1.8 MPa

Claims (1)

A mixture for the device of the lower layers of the pavement base, including an inorganic binder - cement and surfactant, characterized in that the cationic surfactant DON-52KP is used as a surfactant in the following ratio of components,%: Priming 77.89-83.91 Cement 4-6 Water 12-16 DON-52KP 0.09-0.11