阅读说明：本技术 尺寸稳定剂及其制备方法 (Dimensional stabilizer and preparation method thereof ) 是由 钟华 张后禅 于 2021-09-28 设计创作，主要内容包括：本发明揭示了一种尺寸稳定剂及其制备方法。本发明提供的尺寸稳定剂包括疏水剂、生石灰、亚烷基二醇和聚羧酸减水剂。能够显著降低混凝土(板材)的翘曲,降低自收缩和干收缩,混凝土在硬化后的各个龄期,整体无膨胀变形,翘曲与收缩显著降低,做到尺寸稳定,减少开裂。(The invention discloses a size stabilizer and a preparation method thereof. The size stabilizer provided by the invention comprises a hydrophobic agent, quicklime, alkylene glycol and a polycarboxylic acid water reducing agent. The concrete (plate) can be remarkably reduced in warpage, self-shrinkage and dry shrinkage, the whole concrete has no expansion deformation at each age after hardening, the warpage and shrinkage are remarkably reduced, the size is stable, and cracking is reduced.)

1. The size stabilizer is characterized by comprising a hydrophobic agent, quicklime, alkylene glycol and a polycarboxylic acid water reducing agent.

2. The dimensional stabilizer of claim 1, wherein the dimensional stabilizer is liquid at room temperature.

3. The dimensional stabilizer of claim 1, wherein the hydrophobic agent comprises at least one of butyl oleate, butyl n-butyl ester, and liquid butyl stearate.

4. A size stabilizer according to claim 1, wherein the quicklime is in the form of particles comprising calcium oxide or a mixture of calcium oxide and magnesium oxide.

5. The dimensional stabilizer according to claim 4, wherein the quicklime has a particle size of 5 μm to 35 μm.

6. The dimensional stabilizer of claim 1, wherein the alkylene glycol comprises at least one of ethylene glycol, propylene glycol, amino alcohol derivatives, dipropylethynyl ether, diethylene glycol, dipropylene glycol butyl ether, and 2 methyl-2, 4-pentanediol.

7. The dimensional stabilizer according to claim 1, wherein the solids content of the polycarboxylate superplasticizer is 50% or more.

8. A method of preparing a dimensional stabilizer, comprising:

mixing quicklime particles and a water repellent agent for a first time at a first ratio to form a first mixed slurry;

mixing the first mixed slurry with an alkylene glycol in a second ratio for a second time to form a second mixed slurry;

and mixing the second mixed slurry and the polycarboxylate superplasticizer according to a third proportion for a third time to obtain the polycarboxylic acid water reducer.

9. The method of claim 8, wherein the first time period is 0.5 to 3 hours, the second time period is 0.5 to 3 hours, and the third time period is 0.5 to 3 hours.

10. The method for preparing a size stabilizer according to claim 8, wherein the first ratio is at a weight ratio of 95: 5 to 50: 50, the second ratio is at a weight ratio of 10: 90 to 90: 10, and the third ratio is at a weight ratio of 99.5: 0.5 to 90: 10.

Technical Field

The invention relates to the field of architectural chemistry, in particular to a size stabilizer and a preparation method thereof.

Background

Green building and smart construction have been greatly supported and promoted in recent years, with fabricated buildings becoming one of the major points of development. High-performance cement and concrete prefabricated plates are widely applied. In particular, high performance concrete sheets, due to the high loading of cement-based materials and often in low constraint stress conditions, are subject to shrinkage induced cracking, and in addition, sheet member warping is a common problem. This not only makes installation of the components difficult, but also affects the durability of the structure.

At present, CSA, calcium aluminate, compound and HCSA type isoexpansive agent powder are mainly used for controlling the concrete shrinkage in the market. However, the expansion of the formed hydration products such as ettringite, in particular the later expansion, is often detrimental. The swelling agent is also very sensitive to curing conditions, which can lead to failure to achieve the desired properties. In addition, for precast concrete cladding panels, the expansion agent has limited control of the warpage of the panel under low restraint conditions.

The shrinkage reducing agent is used in a relatively small amount, and one of the reasons is that the shrinkage reducing effect is not significant, and the shrinkage reducing rate is low particularly in the early stage of concrete.

Control of sheet warping is often added support, ribbing, or increased sheet thickness, or added fibers or steel reinforcement, which can present cost control and other problems in production, installation, and the like.

Therefore, how to improve the stability of concrete and reduce the warpage and shrinkage cracking of the plate is a problem to be solved in the industry.

Disclosure of Invention

The invention aims to provide a size stabilizer and a preparation method thereof, which can improve the stability of concrete.

In order to solve the above technical problems, according to a first aspect of the present invention, there is provided a dimensional stabilizer comprising a hydrophobizing agent, quicklime, an alkylene glycol and a polycarboxylic acid water reducing agent.

Optionally, the dimensional stabilizer is liquid at room temperature.

Optionally, the hydrophobic agent comprises at least one of butyl oleate, butyl n-butyl ester and liquid butyl stearate.

Optionally, the quicklime is in a granular shape and comprises calcium oxide or a mixture of calcium oxide and magnesium oxide.

Optionally, the particle size of the quicklime is 5-35 μm.

Optionally, the alkylene glycol comprises at least one of ethylene glycol, propylene glycol, amino alcohol derivatives, dipropylethynyl ether, diethylene glycol, dipropylene glycol butyl ether, 2 methyl-2, 4-pentanediol.

Optionally, the solid content of the polycarboxylate superplasticizer is 50% or more.

According to a second aspect of the present invention, there is provided a method for preparing a dimensional stabilizer, comprising:

mixing quicklime particles and a water repellent agent for a first time at a first ratio to form a first mixed slurry;

mixing the first mixed slurry with an alkylene glycol in a second ratio for a second time to form a second mixed slurry;

and mixing the second mixed slurry and the water reducing agent according to a third proportion for a third time to obtain the water reducing agent.

Optionally, the first time is 0.5 to 3 hours, the second time is 0.5 to 3 hours, and the third time is 0.5 to 3 hours.

Optionally, the first ratio is from 95: 5 to 50: 50, the second ratio is from 10: 90 to 90: 10, and the third ratio is from 99.5: 0.5 to 90: 10.

In the size stabilizer and the preparation method thereof provided by the invention, the size stabilizer comprises a hydrophobic agent, quicklime, alkylene glycol and a polycarboxylic acid water reducing agent. The concrete (plate) can be remarkably reduced in warpage, self-shrinkage and dry shrinkage, the whole concrete has no expansion deformation at each age after hardening, the warpage and shrinkage are remarkably reduced, the size is stable, and cracking is reduced.

Drawings

FIG. 1 is a diagram illustrating a warpage test of a general mortar in an embodiment of the present invention;

FIG. 2 is a diagram illustrating a warpage test of high strength mortar according to an embodiment of the present invention;

FIG. 3 is a graph illustrating a concrete shrinkage test according to an embodiment of the present invention.

Detailed Description

The dimensional stabilizers and methods of making the same of the present invention are described in more detail below in conjunction with schematic drawings, which illustrate preferred embodiments of the invention and it is to be understood that those skilled in the art can modify the invention described herein while still achieving the advantageous results of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.

The invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Example 1

The embodiment 1 of the invention provides a size stabilizer for reducing the warping and shrinking of concrete, so that the concrete has no volume expansion after final setting, the warping and shrinking are obviously reduced, the size stability is achieved, and the cracking is controlled.

The size stabilizer comprises a hydrophobic agent, quicklime, alkylene glycol and a water reducing agent.

Typically, the dimensional stabilizers of the present invention are liquid.

One factor considered by the present invention is the warping of the slab due to the humidity gradient of the environment creating a corresponding drying shrinkage gradient within the concrete slab. Warpage due to dimensional changes of concrete caused by moisture gradients, and cracks, dimensional deviations and reduced durability caused by shrinkage are particularly evident for prefabricated large-sized sheets. Therefore, by balancing the design and development of the self-shrinkage and dry shrinkage control mechanism material, the overall shrinkage deformation is reduced, the warpage/flatness is controlled, the cracking is reduced, and the maintenance is reduced.

Specifically, the hydrophobic agent comprises at least one of butyl oleate, butyl n-butyl ester and liquid butyl stearate, and the hydrophobic agent is used for controlling the exchange of water in capillary holes and the outside through the capillary hole blocking and hydrophobic effect, slowing down the water loss process and reducing the humidity gradient, so that the warping is reduced.

Furthermore, the hydrophobic agent and the alkylene glycol have a superposition effect, so that the drying shrinkage gradient can be relieved, and the warping can be reduced.

The alkylene glycol comprises at least one of ethylene glycol, propylene glycol, amino alcohol derivatives, dipropylethynyl ether, diethylene glycol, dipropylene glycol butyl ether, and 2-methyl-2, 4-pentanediol.

In addition, the water repellent agent of the invention has another function of controlling hydration and carboxylation of the quicklime and offsetting early shrinkage of the concrete part.

The alkylene glycol can reduce the surface tension of water in pores with the pore diameter of 2.5nm-50nm, thereby reducing the self-shrinkage and dry shrinkage of concrete at various ages and reducing the warpage caused by humidity gradient.

The hydrophobic agent is capable of reducing the moisture gradient in concrete, the alkylene glycol reduces the surface tension of water, and the alkylene glycol act synergistically to significantly reduce warping.

In the present invention, quicklime is able to provide early micro-expansion, partially counteracting the early shrinkage of the concrete part. The quicklime particles are uniformly mixed with the water repellent and the alkylene glycol liquid, so that chemical reaction (such as a small amount of dissolved water, certain hydroxyl groups in ethylene glycol and the like) between the quicklime and components in the organic liquid is caused under a liquid organic environment, a barrier or a shell is formed around the calcium oxide or CSA particles, the hydration of the high-activity expansibility quicklime or CSA, and the carboxylation by-product or calcium hydroxide are controlled, so that effective and controllable delay of hydration is achieved. Mainly to counteract early shrinkage of part of the concrete.

The quicklime particles may have a particle size of 5 μm to 35 μm, for example 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc.

The CaO quicklime has high expansion rate, and the generated hydration product CSH has no adverse effect on strength and is relatively insensitive to maintenance conditions. But the hydration reaction is fast and is not easy to control. In the size stabilizer provided by the invention, under the liquid environment of a hydrophobic agent such as butyl oleate and the like, the hydration of quicklime is slowed down, and part of early shrinkage is counteracted. The concrete is generally in a shrinkage state, long-term shrinkage is borne by other organic components, a stable shrinkage curve is generated, and dimensional stability at various ages is ensured.

The polycarboxylate water reducing agent is used for providing a dispersing effect, forming a stable liquid and slowing down the hydration speed of quicklime by carboxylation of the quicklime. And the shrinkage reducing agent can be used together with the alkylene glycol shrinkage reducing agent to generate a synergistic effect, so that the overall shrinkage balance of the concrete at different ages can be controlled.

The solid content of the polycarboxylate superplasticizer is 50% or more.

The early shrinkage is partially counteracted by the calcium lime with controllable hydration and carboxylation, and the shrinkage reducing effect caused by the surface tension of the water reduced by the alkylene glycol can last for more than one year, thereby providing guarantee for long-term warping and shrinkage control.

The common expanding agent has limited effect on controlling the warping of concrete and mortar sheets, but the size stabilizer of the invention can reduce the warping of common mortar (concrete) sheets by 38-80% and reduce the warping of high-strength mortar (concrete) sheets by 37-50%.

In the concrete containing 2% by weight of the dimensional stabilizer of the invention, the concrete was substantially in a contracted state after 1 day of water curing, but the total contraction value (self-contraction and dry contraction) was reduced by 40-79%.

Example 2

Embodiment 2 of the present invention provides a method for preparing a size stabilizer, including:

mixing quicklime particles and a water repellent agent for a first time at a first ratio to form a first mixed slurry;

mixing the first mixed slurry with an alkylene glycol in a second ratio for a second time to form a second mixed slurry;

and mixing the second mixed slurry and the water reducing agent according to a third proportion for a third time to obtain the water reducing agent.

Wherein, the first time is 0.5-3h, for example, 1h, 1.5h, 2h, 2.5h, etc., the second time is 0.5-3h, for example, 1h, 1.5h, 2h, 2.5h, etc., and the third time is 0.5-3h, for example, 1h, 1.5h, 2h, 2.5h, etc.

Wherein the first ratio is from 95: 5 to 50: 50, the second ratio is from 10: 90 to 90: 10 and the third ratio is from 99.5: 0.5 to 90: 10.

The size stabilizer prepared by the invention is different from a common expanding agent powder product, and is more accurate in metering and easier to disperse uniformly in concrete due to the fact that the size stabilizer is liquid slurry, and can obviously reduce the warping, deformation and cracking of a concrete precast slab, particularly a large-size concrete thin slab.

Example 3

In the embodiment 3 of the present invention, a specific example is given, and an application alignment experiment of the example is further provided. The size stabilizer components in this example were:

the weight ratio of the butyl oleate to the quicklime to the 2-methyl-2, 4-pentanediol to the polycarboxylic acid water reducer (TS 50%) is 30 to 20 to 47 to 3.

Influence of the mixing amount of the size stabilizer on warping, namely common mortar.

Ordinary mortar is prepared according to the following formula of MN-1(Ref) (blank, without adding size stabilizer): portland cement 460kg/m³155kg/m of water³700ml of polycarboxylic acid high-efficiency water reducing agent (50% TS) is mixed in per 100kg of cement weight, 100g of defoaming agent per 100kg of cement weight, 1720kg/m of river sand (maximum particle size of 2.38mm)³。

MN-2 (the mixing amount of the size stabilizer is 1 percent) is mixed with the same proportion as that of MN-1, but the size stabilizer is added with 1000ml/100kg of cement weight.

MN-3 (2 percent of mixed amount of the size stabilizer) is mixed with the same proportion as that of MN-1, but 2000ml of the size stabilizer is added per 100kg of cement weight.

MN-4 (size stabilizer added with 3% CSA) is mixed with the same proportion as MN-1, but added with CSA expansion agent type size stabilizer of 3000ml/100kg cement weight.

Test method

Making a batten with the thickness of 1cm, the width of 10cm and the length of 100cm, curing the batten with water for one day, taking out the batten and drying the batten, and coating waterproof silica gel on the other surfaces except the head-on surface (the surface with the width of 10cm and the length of 100 cm). The panel was then placed in an environment with humidity (40 + -3)%, temperature (26 + -3) ° c, and the warpage (median maximum deflection) of the panel was measured for 1 day, 7 days, 14 days, 21 days, and 28 days.

As shown in figure 1, the warpage of the mortar added with 1% of the size stabilizer after 1 day of water curing is reduced by 38% to 65% compared with the reference proportion; compared with the reference mixture ratio, the warpage of the mortar doped with 2 percent of size stabilizer after 1 day of water curing is reduced by 49 percent to 80 percent; compared with the reference mixture ratio, the warpage of the mortar doped with the 3% CSA expanding agent after 1-day water curing is not obviously changed.

High-strength mortar with influence of size stabilizer mixing amount on warping

High strength mortar ratioMH-1(Ref) (blank, without incorporation of a dimensional stabilizer): portland cement 730kg/m³100kg/m of silica fume³183kg/m of water³1300ml of polycarboxylic acid high-efficiency water reducing agent (50 percent TS) per 100kg of cement weight and 1430kg/m of quartz sand (maximum particle size of 2.38mm)³。

The proportion of the high-strength mortar is MH-2 (2 percent of the mixed amount of the size stabilizer) and the same as MH-1, but 2000ml of the size stabilizer is added in per 100kg of cement weight.

Test method

Making a batten with the thickness of 1cm, the width of 10cm and the length of 100cm, curing the batten with water for one day, taking out the batten and drying the batten, and coating waterproof silica gel on the other surfaces except the head-on surface (the surface with the width of 10cm and the length of 100 cm). The panel was then placed in an environment with humidity (40 + -3)%, temperature (26 + -3) ° c, and the warpage (median maximum deflection) of the panel was measured for 1 day, 7 days, 14 days, 21 days, and 28 days.

As shown in FIG. 2, the warpage of the high-strength mortar added with 2% of the size stabilizer after 1 day of water curing is reduced by 37% to 50% compared with the reference mixture ratio.

Effect of the amount of the size stabilizer on the shrinkage of concrete

The proportion of the high-strength concrete is CH-1: portland cement 620kg/m³70kg/m of silica fume³152kg/m of water³690kg/m of coarse aggregate (maximum particle diameter 10mm)³760kg/m of quartz sand (maximum particle size 2.38mm)³1200ml of polycarboxylic acid high-efficiency water reducing agent (50% TS) per 100kg of cement weight.

The proportion of the high-strength concrete is CH-3 (the mixing amount of the size stabilizer is 2 percent), the proportion is the same as that of CH-1, but 2000ml of the size stabilizer is added per 100kg of the weight of the cement.

As shown in FIG. 3, the total shrinkage of the concrete with 2% of the size stabilizer after 1 day of water curing was reduced by 45% to 79% compared to the reference formulation.

The concrete shrinkage test was carried out according to the GB50080 standard.

From the above experiments, it can be derived:

the size stabilizer can reduce the warpage of common mortar and high-strength mortar by 38-80%.

CSA bulking agents have little effect on warpage.

Mortar (concrete) slabs with 2% addition of dimensional stabilizer showed 38-80% less warpage after 1 day water curing compared to slabs without addition of dimensional stabilizer.

The concrete doped with 2% of size stabilizer is in a shrinkage state after being cured for 1 day in water; the size stabilizer can reduce the shrinkage of the concrete slab by 38-57%.

The dimensional stabilizer provides balanced control of warpage and shrinkage over various ages.

In conclusion, the size stabilizer provided by the invention controls the exchange of water in the capillary holes with the outside through the capillary hole blocking and hydrophobic effects of the hydrophobic agent, reduces the humidity gradient and reduces the warpage. Hydration and carboxylation of the quicklime are controlled by the hydrophobing agent, and early shrinkage of the concrete part is counteracted. The hydrophobic agent and the alkylene glycol have a superposition effect, so that the drying shrinkage gradient can be relieved, and the warping can be reduced. The quicklime is uniformly mixed with the hydrophobing agent and the alkylene glycol liquid, so that the chemical reaction between the quicklime and the components in the organic liquid is caused under the organic environment of the hydrophobing agent liquid, the hydration of the high-activity expansible quicklime or CSA, and the carboxylation by-product or calcium hydroxide are controlled to achieve effective controllable delay hydration and mainly used for counteracting part of early shrinkage of concrete.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.