A kind of thermal reversible repair mortar and preparation method thereof

Abstract

The present invention provides a thermally reversible repair mortar and a preparation method thereof. The components and contents of the thermally reversible repair mortar are: 100-120 parts of cement, 90-100 parts of quartz sand, 24-26 parts of water, 10-16 parts of silica fume, 1-3 parts of water reducer, 30-40 parts of thermally reversible particles, and 10-20 parts of thermally reversible powder; the preparation method of the thermally reversible repair mortar is: S1, preparation of cementitious material dry material; S2, preparation of moist thermally reversible powder; S3, preparation of aggregate dry material; S4, preparation of thermally reversible repair mortar; S5, mortar pouring and curing. The present invention can achieve thermal reversibility of mortar strength by adding a variety of thermally reversible components. The prepared mortar can not only ensure the strength required for normal use, but also meet the reversible requirements during the repair of important historical structures, which is of great significance to important historical structures.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a thermally reversible repair mortar and a preparation method thereof. Background Art

[0002] Traditional historical buildings inherit China's ancient culture and architectural style, but with the continuous influence of the external environment, some historical buildings are severely damaged. At this time, they need to be repaired or rebuilt according to traditional techniques. For small-scale repairs, the repairs are often required to be reversible, but the existing technology is often irreversible for the repair of historical buildings and causes certain damage.

[0003] In construction projects, dry-mix mortar is a dry powder mixed with raw materials such as cementitious materials, aggregates and additives. As a powder, the use of different components is often accompanied by component separation, uneven distribution of components and poor product quality due to differences in density and hydrophilicity.

[0004] The fire resistance limit of cement mortar is between 200℃ and 300℃. Temperatures exceeding 200℃ have a significant impact on the properties of materials such as concrete or stone structures. Therefore, there is an urgent need to find a mortar and preparation method that can both meet strength requirements and have repair reversibility. Summary of the invention

[0005] The object of the present invention is to provide a thermally reversible repair mortar and a preparation method thereof, so as to solve the problems in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: In a first aspect, the present invention provides a thermally reversible repair mortar, wherein the components and contents thereof are as follows in percentage by mass:

[0007] 100-120 parts of cement, 90-100 parts of quartz sand, 24-26 parts of water, 10-16 parts of silica fume, 1-3 parts of water reducing agent, 30-40 parts of thermally reversible particles, and 10-20 parts of thermally reversible powder.

[0008] Preferably, the water reducer is a polycarboxylate water reducer.

[0009] Preferably, the components of the thermoreversible particles and the thermoreversible powder are both ethylene-vinyl acetate copolymer.

[0010] Preferably, the softening point of the thermoreversible particles and the thermoreversible powder is 160°C.

[0011] Preferably, the thermoreversible particles are spherical particles with a particle size of 2.5-3.5 mm, and the thermoreversible powder is an ultrafine powder with a particle size of less than 1 μm and a specific surface area of ​​300-400 m 3 / kg.

[0012] Preferably, the quartz sand is natural sand with a diameter of ≤4.75 mm.

[0013] The present invention provides a method for preparing the thermoreversible repair mortar according to the first aspect of the present invention in a second aspect, comprising the following steps:

[0014] S1. Preparation of dry cementitious material:

[0015] Measuring cement, silica fume and water reducing agent and mixing them;

[0016] S2. Preparation of wet thermoreversible powder:

[0017] Thermoreversible powder and water are measured and stirred thoroughly;

[0018] S3. Preparation of dry aggregate:

[0019] The quartz sand and the thermoreversible particles are metered and mixed and stirred;

[0020] S4. Preparation of thermally reversible repair mortar:

[0021] Measure and mix the dry cementitious material and the moistened thermoreversible powder. After stirring for 3 minutes, add the dry aggregate and continue to mix and stir at a stirring speed of 800 to 1500 r / min for 10 minutes.

[0022] S5. Mortar pouring and curing:

[0023] The thermoreversible repair mortar was injected into the mold and cured for 28 days at 20-30°C and 95% humidity.

[0024] Preferably, the thermally reversible particles and the thermally reversible powder have the same diameter as quartz sand and silica fume, respectively.

[0025] The present invention has at least the following beneficial effects:

[0026] (1) The present invention provides a thermoreversible repair mortar and a preparation method thereof. By adding a plurality of thermoreversible components, the mortar can exhibit high strength characteristics at room temperature, which can meet the requirements of normal use conditions. In some structural repair conditions, the mortar can be heated to 160° C. to make it exhibit low strength characteristics, which greatly improves the application range of the mortar.

[0027] (2) The present invention provides a thermally reversible repair mortar and a preparation method thereof. The added thermally reversible powder can be mixed with the cementitious material dry material after a certain degree of wetting treatment, so as to achieve the component uniformity required for construction and pouring, thereby improving the product quality of the mortar. The added thermally reversible particles have a certain hardness and modulus at room temperature because the diameter of the thermally reversible material is consistent with that of the replaced quartz sand and silica fume, thereby ensuring the product quality of the mortar, so that the mortar still has a high strength (up to 30MPa) at a temperature below about 100 degrees.

[0028] (3) The present invention provides a thermally reversible repair mortar and a preparation method thereof. The thermally reversible particles and powders have good structural stability, so that the prepared mortar has good thermal cycle stability. The present invention can achieve thermal reversibility of mortar strength by adding a variety of thermally reversible components. The prepared mortar can not only ensure the strength required for normal use, but also meet the reversibility requirements of important historical structure repair conditions, which is of great significance to important historical structures. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] A thermally reversible repair mortar, the components and contents of which are as follows in parts by mass:

[0032] 120 parts of cement, 90 parts of quartz sand, 24 parts of water, 10 parts of silica fume, 1 part of water reducing agent, 30 parts of thermally reversible particles, and 10 parts of thermally reversible powder.

[0033] The thermally reversible particles are spherical particles with a particle size of 2.5 mm; the thermally reversible powder is an ultrafine powder with a particle size of less than 1 μm and a specific surface area of ​​300 to 400 m 3 / kg; quartz sand is natural sand with a diameter of ≤4.75mm; the thermally reversible particles and the thermally reversible powder have the same diameter as the quartz sand and silica fume, respectively.

[0034] The preparation method of the thermally reversible repair mortar comprises the following steps:

[0035] S1. Preparation of dry cementitious material:

[0036] Measure and mix 120 parts of cement, 10 parts of silica fume and 1 part of water reducing agent;

[0037] S2. Preparation of wet thermoreversible powder:

[0038] Measure 10 parts of thermoreversible powder and 2 parts of water and stir thoroughly;

[0039] S3. Preparation of dry aggregate:

[0040] 90 parts of quartz sand and 30 parts of thermoreversible particles were weighed and mixed;

[0041] S4. Preparation of thermally reversible repair mortar:

[0042] Measure and mix the dry S1 cementitious material and the moistened thermoreversible powder of S2. After stirring for 3 minutes, add the dry S3 aggregate and continue to mix and stir at a speed of 800 r / min for 10 minutes.

[0043] S5. Mortar pouring and curing:

[0044] The S4 thermoreversible repair mortar was injected into the mold, cured for 28 days at 25° C. and 95% humidity, and hardened to obtain a thermoreversible repair mortar material.

[0045] Example 2

[0046] A thermally reversible repair mortar, the components and contents of which are as follows in parts by mass:

[0047] 114 parts of cement, 90 parts of quartz sand, 24 parts of water, 10 parts of silica fume, 1 part of water reducing agent, 30 parts of thermally reversible particles, and 16 parts of thermally reversible powder.

[0048] The thermally reversible particles are spherical particles with a particle size of 3 mm; the thermally reversible powder is an ultrafine powder with a particle size of less than 1 μm and a specific surface area of ​​300 to 400 m 3 / kg; quartz sand is natural sand with a diameter of ≤4.75mm; the thermally reversible particles and the thermally reversible powder have the same diameter as the quartz sand and silica fume, respectively.

[0049] The preparation method of the thermally reversible repair mortar comprises the following steps:

[0050] S1. Preparation of dry cementitious material:

[0051] Measure and mix 114 parts of cement, 10 parts of silica fume and 1 part of water reducing agent;

[0052] S2. Preparation of wet thermoreversible powder:

[0053] Measure 16 parts of thermoreversible powder and 2 parts of water and stir thoroughly;

[0054] S3. Preparation of dry aggregate:

[0055] 90 parts of quartz sand and 30 parts of thermoreversible particles were weighed and mixed;

[0056] S4. Preparation of thermally reversible repair mortar:

[0057] Measure and mix the dry material S1 cementitious material and the moistened thermoreversible powder S2. After stirring for 3 minutes, add the dry material S3 aggregate and continue to mix and stir at a stirring speed of 1000 r / min for 10 minutes.

[0058] S5. Mortar pouring and curing:

[0059] The S4 thermoreversible repair mortar was injected into the mold, cured for 28 days at 25° C. and 95% humidity, and hardened to obtain a thermoreversible repair mortar material.

[0060] Example 3

[0061] A thermally reversible repair mortar, the components and contents of which are as follows in parts by mass:

[0062] 100 parts of cement, 90 parts of quartz sand, 24 parts of water, 15 parts of silica fume, 1 part of water reducing agent, 40 parts of thermally reversible particles, and 20 parts of thermally reversible powder.

[0063] The thermally reversible particles are spherical particles with a particle size of 3.5 mm; the thermally reversible powder is an ultrafine powder with a particle size of less than 1 μm and a specific surface area of ​​300 to 400 m 3 / kg; quartz sand is natural sand with a diameter of ≤4.75mm; the thermally reversible particles and the thermally reversible powder have the same diameter as the quartz sand and silica fume, respectively.

[0064] The preparation method of the thermally reversible repair mortar comprises the following steps:

[0065] S1. Preparation of dry cementitious material:

[0066] Measure and mix 100 parts of cement, 15 parts of silica fume and 1 part of water reducing agent;

[0067] S2. Preparation of wet thermoreversible powder:

[0068] Measure 20 parts of thermoreversible powder and 2 parts of water and stir thoroughly;

[0069] S3. Preparation of dry aggregate:

[0070] 90 parts of quartz sand and 40 parts of thermoreversible particles were weighed and mixed;

[0071] S4. Preparation of thermally reversible repair mortar:

[0072] Measure and mix the dry material S1 cementitious material and the moistened thermoreversible powder S2. After stirring for 3 minutes, add the dry material S3 aggregate and continue to mix and stir at a speed of 1500 r / min for 10 minutes.

[0073] S5. Mortar pouring and curing:

[0074] The S4 thermoreversible repair mortar was injected into the mold, cured for 28 days at 20° C. and 95% humidity, and hardened to obtain a thermoreversible repair mortar material.

[0075] In the above Examples 1-3, the water reducer is a polycarboxylic acid water reducer; the components of the thermoreversible particles and the thermoreversible powder are both ethylene-vinyl acetate copolymer (EVA); and the softening point of the thermoreversible particles and the thermoreversible powder is 160°C.

[0076] The above embodiments 1-3 provide a thermally reversible repair mortar and a preparation method thereof. The thermally reversible particles and thermally reversible powder are prepared by replacing aggregates and silica fume of the same diameter as dry materials. By using the same diameter, various components can be evenly mixed.

[0077] The mortars prepared in the above Examples 1-3 were subjected to strength tests, and the results are shown in the following table:

[0078]

[0079] In summary, the mortars prepared in Examples 1-3 have the same strength as conventional mortars at room temperature, and the strength after heating is about 5 MPa, and are easy to peel off.

[0080] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0081] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A thermally reversible repair mortar, characterized in that: The components and contents are as follows: 100-120 parts of cement, 90-100 parts of quartz sand, 24-26 parts of water, 10-16 parts of silica fume, 1-3 parts of water reducing agent, 30-40 parts of thermally reversible particles, 10-20 parts of thermally reversible powder; The components of the thermally reversible particles and thermally reversible powder are both ethylene-vinyl acetate copolymer; The softening point of the thermoreversible particles and the thermoreversible powder is 160°C.

2. A thermally reversible repair mortar according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer.

3. A thermally reversible repair mortar according to claim 1, characterized in that: The thermally reversible particles are spherical particles with a particle size of 2.5-3.5 mm, and the thermally reversible powder is an ultrafine powder with a particle size of less than 1 μm and a specific surface area of ​​300-400 m³ / kg.

4. The thermally reversible repair mortar according to claim 1, characterized in that: The quartz sand is natural sand with a diameter of ≤4.75 mm.

5. A method for preparing a thermoreversible repair mortar according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Preparation of dry cementitious material: Measuring cement, silica fume and water reducing agent and mixing them; S2. Preparation of wet thermoreversible powder: Thermoreversible powder and water are measured and stirred thoroughly; S3. Preparation of dry aggregate: The quartz sand and the thermoreversible particles are metered and mixed and stirred; S4. Preparation of thermally reversible repair mortar: Measure and mix the cementitious material dry material and the moistened thermoreversible powder. After stirring for 3 minutes, add the aggregate dry material and continue to mix and stir at a stirring speed of 800-1500 r / min for 10 minutes. S5. Mortar pouring and curing: The thermoreversible repair mortar was injected into the mold and cured for 28 days at 20-30°C and 95% humidity.

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