CN1587180A - High performance cement base self leveling material - Google Patents

Abstract

The high performance self-leveling cement base material used in building engineering consists of portland cement 25-35 wt%, flyash 3.2-4.5 wt%, fine silica powder 0-3.0 wt%, slag 2.8-4.0 wt%, building sand 50-63 wt%, expanding agent 3.27-3.7 wt% and high efficiency water reducing agent 0.23-0.40 wt%. The present invention has the advantages of wide material source, low cost and capacity of reducing environmental pollution, and the hardened material has high density, high anti-seepage performance and high adhesion.

Description

High-performance cement-based self-leveling material

technical field

The invention relates to a cement-based self-leveling material, in particular to a high-performance cement-based self-leveling material used for ground leveling or building structure repair and reinforcement. Used in the technical field of building materials.

Background technique

As an important part of the building, the quality of the ground has attracted great attention. During the construction of the building ground, the following common problems often occur: the ground is uneven, sandy, pockmarked, Ground damage, etc., on the completed ground, plaster or transfer mortar and concrete, resulting in a lot of ash bumps on the ground. In the past, the usual treatment method was to chisel the ground, and then spread a layer of 2cm thick mortar on it, which was labor-intensive, time-consuming, and material-intensive. It could not guarantee the flatness of the ground, and increased the weight of the ground floor. In response to the above problems, a reform was carried out on the traditional ground materials, and a new material - self-leveling material for the ground was proposed. Initially, self-leveling materials were mainly gypsum-based, but their water resistance was relatively poor, and because they were neutral or acidic, there was a risk of corrosion to steel bars, so their scope of use was limited. Therefore, the development and research of cement-based self-leveling materials has attracted international attention, and products have come out one after another.

After searching the literature of the prior art, it was found that Wang Xuesen et al. wrote the article "Research on Low-heat Super Self-Leveling Mortar" in "Building Technology Development" Volume 29, No. 4, 2002.4, P33-35. The super self-leveling mortar of granulated blast furnace slag and silicon powder is mainly used for grouting reinforcement projects. This self-leveling mortar effectively reduces the heat of hydration due to the addition of a large amount of granulated blast furnace slag, thus avoiding the High hydration temperature causes shrinkage cracks. But this kind of self-leveling mortar is not suitable for ground leveling. In addition, this kind of self-leveling mortar has a large loss of fresh mortar expansion over time, poor segregation resistance and bleeding ability, and cannot fully meet the requirements of mortar mixing, transportation, pumping and construction. Compared with traditional plastering mortar, raw materials The requirements are high, the price is very expensive, and it is difficult to promote and use it in a large area.

Contents of the invention

The purpose of the present invention is to provide a high-performance cement-based self-leveling material for the deficiencies and defects in the prior art, so that it can be used for self-leveling of the ground, old ground, sandy ground and unqualified ground repair and some special For the reinforcement and repair of building structures, the formula and production process of the material can be adjusted appropriately, and it can be used as a grouting material.

The present invention is achieved through the following technical solutions, each component of the present invention and weight percentage thereof are:

Ordinary Portland cement 25～35%

Fly ash 3.2～4.5%

Micro silica fume 0～3.0%

Slag 2.8～4.0%

Construction sand 50～63%

Expansion agent 3.27～3.7%

Superplasticizer 0.23～0.40%

The invention is prepared by uniformly mixing ordinary Portland cement, fly ash, slag, microsilica fume, building sand, expansion agent and high-efficiency water reducing agent in a certain proportion and packing them in bags. The basic performance of high-performance cement-based self-leveling materials is mainly achieved by using commercially available common building materials:

1. Use fly ash, slag and micro-silica fume to partially replace Portland cement, use fly ash and slag to improve the flow performance of the mixture, and use micro-silica fume to improve the water retention of the mixture and improve the strength and compactness of the self-leveling mortar sex. In this way, the cost can be greatly reduced, and the environmental pollution can be reduced, and the waste can be effectively used. Portland cement with a strength grade of 425 should be used for cement, grade I fly ash should be used for fly ash, finely ground slag should be used for slag, and micro silica fume should be provided by Elken Company, with a particle size of about 0.01-0.1 μm .

2. Use ordinary construction sand that meets the requirements of JGJ52-92 "Quality Standards and Test Methods for Ordinary Concrete Sand". Strictly control the gradation of the sand and then mix the sand after grading to greatly improve the fluidity of the mortar and reduce the price. The amount of organic admixtures. The sand used in the self-leveling mortar of the present invention should meet the following particle size and gradation requirements:

2.500～5.000mm 0～6% (weight ratio)

1.250～2.500mm 20～35% (weight ratio)

0.315～1.250mm 55～65% (weight ratio)

＜0.315mm 10～15% (weight ratio)

That is, the fineness modulus of the sand is in the range of 2.7 to 2.9.

3. The expansion agent is mixed with non-air-entraining expansion agent calcium aluminate, which produces volume expansion through chemical reaction, so that the drying shrinkage of the mortar is compensated and the mortar is denser. The amount of expansion agent should be controlled within the range that can compensate for the dry shrinkage of the mortar and a slight expansion, and its amount is 5-10% of the cementitious material.

4. The high-efficiency water reducer is the powder of naphthalenesulfonate-based high-efficiency water reducer in the present invention, and the addition amount is 0.50-1.2% of the gelling material. In order for the mortar to achieve self-leveling and have greater fluidity, it is necessary to add an appropriate amount of high-efficiency water reducer.

The preparation method of the present invention is: according to the proportion of the formula, the required ordinary Portland cement, fly ash, slag, microsilica fume, construction sand, expansion agent and high-efficiency water reducer are weighed, fully stirred in a mixer, The product is formed and bagged. When used on site, add mixing water with 40-45% of the weight of the cementitious material.

The invention has the advantages of: using conventional building materials, it has the advantages of wide source of raw materials and low cost; in the raw materials, fly ash and slag are used to partially replace cement, on the one hand, waste utilization can reduce environmental pollution and reduce cement consumption , to save energy, on the other hand, by adding powder magnesium ash and slag, using its glass bead effect to improve the fluidity of the mixture, reduce the amount of chemical admixtures, and reduce costs; use silica fume to partially replace cement to improve self-leveling Mortar water retention and hardened strength and compactness; bagged on-site mixing, reducing environmental pollution, easy operation, self-leveling, reducing labor costs; compensation and slight expansion by adding non-air-entraining expansion agent , so that the hardened material has the characteristics of high density, high impermeability, high adhesion, and good stability and water retention.

Detailed ways

The following embodiments are provided in conjunction with the contents of the present invention:

High-performance cement-based self-leveling mortar is composed of ordinary Portland cement, fly ash, slag, microsilica fume, construction sand, expansion agent and high-efficiency water reducing agent. By inventing the formula, the required properties can be obtained.

Example 1

Ordinary Portland cement 25

Fly ash 3.2

Micro silica fume 2.0

Slag 2.8

Construction sand 63.0

Expansion agent 3.7

High-efficiency water reducer 0.30

The above components are prepared according to the aforementioned process to prepare high-performance cement-based self-leveling mortar dry powder, add tap water with a mass of 0.45 of the cementitious material, and stir. The measured properties are as follows: the degree of expansion is 280mm, and the compressive strength (7 days) is 38.5MPa , flexural strength (7 days) 6.52MPa;

   Compressive strength (28 days) 59.3MPa, flexural strength (28 days) 8.76MPa; expansion rate 7 days: 0.024%, 28 days 0.026%, 56 days 0.027%

Example 2

Ordinary Portland cement 30.0

Fly ash 3.04

Micro silica fume 0

Slag 3.04

Construction sand 60.0

Expander 3.5

Superplasticizer 0.42

The above components are prepared according to the aforementioned process to prepare high-performance cement-based self-leveling mortar dry powder, add tap water with a mass of 0.45 of the cementitious material, and stir. The measured properties are as follows: the degree of expansion is 290mm, and the compressive strength (7 days) is 34.0MPa , flexural strength (7 days) 6.28MPa;

  Compressive strength (28 days) 50.5MPa, flexural strength (28 days) 8.54MPa; expansion rate 7 days: 0.026%, 28 days 0.028%, 56 days 0.029%

Embodiment 3 (all are mass ratio in the example)

Ordinary Portland cement 35.0

Fly ash 4.5

Micro silica fume 3.0

Slag 4.0

Construction sand 50.0

Expanding agent 3.27

Superplasticizer 0.23

The above components are prepared according to the aforementioned process to prepare high-performance cement-based self-leveling mortar dry powder, add tap water with a mass of 0.45 of the cementitious material, and stir. The measured properties are as follows: the degree of expansion is 290mm, and the compressive strength (7 days) is 37.0MPa , flexural strength (7 days) 6.50MPa;

  Compressive strength (28 days) 60.5MPa, flexural strength (28 days) 9.0MPa Expansion rate 7 days: 0.025%, 28 days 0.028%, 56 days 0.030%

Claims (4)

1, a kind of high-performance cement based self-leveling material is characterized in that, each component and weight percent thereof are:

Ordinary Portland cement 25～35%

Flyash 3.2～4.5%

SILICA FUME 0～3.0%

Slag 2.8～4.0%

Building sand 50～63%

Swelling agent 3.27～3.7%

High efficiency water reducing agent 0.23～0.40%.

2, the described high-performance cement based self-leveling material of claim 1 is characterized in that, described building sand must meet following particle diameter and grating requires:

2.500～5.000mm 0～6% weight ratio

1.250～2.500mm 20～35% weight ratios

0.315～1.250mm 55～65% weight ratios

＜0.315mm 10～15% weight ratios.

3, the described high-performance cement based self-leveling material of claim 1 is characterized in that, it is Powdered that described high efficiency water reducing agent is that naphthalenesulfonate is.

4, the described high-performance cement based self-leveling material of claim 1 is characterized in that, described swelling agent is the calcium aluminate class.