Cement mortar for improving crack resistance of concrete drainage pipe and preparation method thereof

Abstract

The present invention relates to a cement mortar for improving the crack resistance of concrete drainage pipes and a preparation method thereof. The invention belongs to the field of building materials technology and exhibits the characteristics of compression resistance, crack resistance, and uniform distribution. The invention utilizes polyether-type spandex fiber, medium river sand, and silicate PI cement as primary raw materials. Portland cement has high strength, and the polyether-type spandex fiber has the advantages of high strength and chemical stability. The medium river sand has the characteristics of moderate particle size, smooth surface, and low impurity content. The smooth surface reduces wear and damage to building materials. The combination of these multiple high-performance materials significantly improves the strength and durability of cement mortar concrete. Furthermore, the pretreated spandex fiber, due to the principle of mutual repulsion between like charges, is chemically dispersed with the components of the cement mortar by a dispersant, thereby improving the overall strength, permeability resistance, and crack resistance of the cement mortar.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and in particular relates to a cement mortar for improving the crack resistance of a concrete drainage pipe and a preparation method thereof. Background Art

[0002] Concrete drainage pipes are widely used in urban drainage systems and play a vital role in infrastructure and urban development. The cement mortar used to caulk concrete drainage pipes is typically a mixture of cement, sand, and water. However, due to factors such as pipe materials and the construction environment, traditional cement mortar often shrinks during the drying process, making the pipes prone to cracking, affecting their service life and safety.

[0003] In order to improve the crack resistance, it is necessary to provide a cement mortar with good crack resistance and a preparation method thereof. Summary of the Invention

[0004] To address the problems of the existing technology and improve the crack resistance of the material, we have introduced a new admixture material - spandex. The present invention provides a cement mortar for improving the crack resistance of concrete drainage pipes, which has the characteristics of compression resistance, crack resistance and uniform distribution.

[0005] Another object of the present invention is to provide a method for preparing cement mortar and a construction process thereof for improving the crack resistance of concrete drainage pipes.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0008] In particular, the cement includes at least one of P·O cement, P·I cement, P·II cement, P·III cement, P·IV cement and P·V cement, preferably P·I cement, which has the advantages of high strength, stable performance and good crack resistance, and can improve the overall strength and crack resistance of cement mortar.

[0009] In particular, the sand includes at least one of sea sand, river sand and mountain sand, and is preferably medium sand among river sand. Medium sand has the characteristics of moderate particles, smooth surface and low impurity content. It is used as a raw material for preparing cement mortar, which can enhance the strength and durability of concrete. The smooth surface can reduce wear and damage to building materials, which is beneficial to protecting buildings.

[0010] In particular, the dispersant comprises at least one of lignin sulfonate, polycarboxylate, acrylate, and polymer emulsion. A lignin sulfonate dispersant is preferred. The dispersant's primary working principle is to increase the surface charge of the particles, forming a layer of ions or polar groups opposite to the particles on the particle surface, thereby generating electrostatic attraction. This alters the interaction between the particles and the liquid, causing the particles to repel each other and remain suspended in the liquid, thereby achieving a dispersing effect. Chemical bonds form between the dispersant and the cement mortar components, resulting in more uniform mixing of the various components of the cement mortar. Without compromising the rheological properties of the cement mortar, the dispersant reduces water usage, increases mortar density, reduces pump pressure, and thus improves mortar pumpability, making pouring smoother and overall improving the strength, permeability, and crack resistance of the cement mortar.

[0011] In particular, the spandex fiber includes at least one of polyester spandex fiber and polyether spandex fiber prepared from polyamino polymers or copolymers, preferably polyether spandex fiber. Polyether spandex fiber has the advantages of high strength, good wear resistance and stable chemical properties, and can improve the stability and crack resistance of cement mortar as a whole.

[0012] The mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:m SF , where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SF Indicates the mass percentage of spandex fiber; the content of the dispersant is selected to be 2%-4% of the mass of the spandex fiber;

[0013] The amount of spandex fiber is m SF Calculated by the total volume fraction of cement mortar, the content includes 0%, 0.39%, 0.58%, 0.77%, 0.96% and 1.15%, wherein the amount of spandex fiber is m SF Calculated according to the total volume fraction of cement mortar, where 0% is 1m 3 No spandex fiber is added to cement mortar, 0.39% is 1m 3 Add 30kg spandex fiber to cement mortar, 0.58% for 1m 3 Add 45kg spandex fiber to cement mortar, 0.77% for 1m 3 Add 60kg spandex fiber to cement mortar, 0.96% for 1m 3 Add 75kg spandex fiber and 1.15% to 1m 3Add 90kg of spandex fiber to the cement mortar.

[0014] The spandex fiber is a pre-treated spandex fiber material, and the processing method includes the following steps:

[0015] Tearing: Place the spandex fiber on the table, cut it into small pieces of 20-50mm in length with a knife, and then tear it apart with your hands. Pay attention to the strength used to avoid damaging the fiber structure to obtain short spandex fibers;

[0016] Drying: Place the torn short spandex fibers in an oven at 100-120°C for 1-2 hours to obtain dry short spandex fibers;

[0017] Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator. The electrostatic generator uses high-voltage corona discharge to charge the surface of the spandex with static electricity. The charged spandex fibers are polarized with negative charges under the action of the electrostatic field to obtain treated spandex fibers.

[0018] The above-mentioned pretreated spandex fiber can increase the adhesion between the fiber and the cement mortar due to the principle of mutual repulsion of like charges through electrostatic treatment. Under the synergistic effect of the dispersant, the spandex fiber will be more evenly dispersed in the cement mortar, thereby increasing the adhesion between the spandex fiber and the cement mortar as a whole, thereby improving the strength and crack resistance of the cement mortar.

[0019] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0020] Weigh the raw materials according to the ratio, put the cement, sand and water into the mixer, stir and mix for 5-10 minutes, then add the treated spandex fiber and dispersant, continue to stir and mix for 10-15 minutes to obtain cement mortar.

[0021] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0022] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0023] Beneficial effects of the present invention:

[0024] Compared with the prior art, the present invention selects polyether spandex fiber, medium sand from river sand, and silicate PI cement as main raw materials. The polyether spandex fiber has the advantages of high strength, good wear resistance and stable chemical properties; the medium sand has the characteristics of moderate particle size, smooth surface and low impurity content. The smooth surface can reduce wear and damage to building materials and is beneficial to protecting buildings; the silicate cement has high strength. The combination of multiple excellent performance materials can greatly improve the strength and durability of cement mortar concrete. Moreover, the spandex fiber after pretreatment can increase the adhesion of the fiber to the cement mortar due to the principle of mutual repulsion of like charges. Under the synergistic effect of the dispersant, by increasing the surface charge of the spandex fiber and the mortar particles, a layer of opposite ions is formed on the surface, thereby generating electrostatic attraction, which changes the interaction force between the spandex fiber and the mortar. A chemical reaction also occurs between the dispersant and the mortar. Under the chemical action force, the spandex fiber will be more evenly dispersed in the cement mortar. Without destroying the rheological properties of the cement mortar, the amount of water used can be reduced, the density of the mortar can be increased, the pump pressure can be reduced, and the pumpability of the mortar can be improved, making pouring smoother and improving the strength, permeability resistance and crack resistance of the cement mortar as a whole.

[0025] The cement mortar for caulking concrete drainage pipes prepared using this method exhibits significant crack resistance, effectively extending their service life, reducing maintenance costs, and improving the reliability of municipal engineering projects. The application of this technology is expected to generate positive economic and social benefits in the field of concrete drainage pipes. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, features and effects of the present invention are described in detail below in conjunction with the embodiments.

[0027] Example 1

[0028] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0029] The cement is PI cement; the sand is medium river sand; the spandex fiber is polyether spandex fiber; and the dispersant is lignin sulfonate dispersant.

[0030] Furthermore, the mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:0, where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, mw Indicates the water mass percentage and m SF Indicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 3% of the mass of the spandex fiber; the amount of the spandex fiber is m SF Calculated according to the total volume fraction of cement mortar, where 0% is 1m 3 No spandex fiber is added to the cement mortar.

[0031] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0032] The raw materials were weighed according to the ratio, and cement, sand and water were put into a mixer, stirred and mixed for 5 minutes, and then continued to stir and mix for 15 minutes to obtain cement mortar.

[0033] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0034] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0035] After concrete pipe construction is complete, proper curing is required. Wet curing and covering membranes help maintain the concrete's moisture and temperature to ensure its full development of strength and crack resistance. During use, regular monitoring and maintenance can extend the life of the drainage pipe. Regular inspections and repairs of any cracks and damage ensure the pipe's reliability and durability.

[0036] Example 2

[0037] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0038] The cement is PI cement; the sand is medium river sand; the spandex fiber is polyether spandex fiber; and the dispersant is lignin sulfonate dispersant.

[0039] Furthermore, the mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:0.39, where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SFIndicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 3% of the mass of the spandex fiber; the amount of the spandex fiber is m SF Calculated based on the total volume fraction of cement mortar, 0.39% is 1m 3 Add 30kg of spandex fiber to the cement mortar.

[0040] The spandex fiber is a pre-treated spandex fiber material, and the processing method includes the following steps:

[0041] Tearing: Place the spandex fiber on the table, cut it into 30mm long segments with a knife, and then tear it apart with your hands. Pay attention to the strength used to avoid damaging the fiber structure to obtain short spandex fibers.

[0042] Drying: Place the torn short spandex fibers in an oven at 120°C for 1.5 hours to obtain dry short spandex fibers;

[0043] Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator. The electrostatic generator uses high-voltage corona discharge to charge the surface of the spandex with static electricity. The charged spandex fibers are polarized with negative charges under the action of the electrostatic field to obtain treated spandex fibers.

[0044] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0045] The raw materials were weighed according to the ratio, and cement, sand and water were put into a mixer and stirred for 5 minutes. Then, the treated spandex fiber and dispersant were added and the stirring was continued for 15 minutes to obtain cement mortar.

[0046] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0047] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0048] After concrete pipe construction is complete, proper curing is required. Wet curing and covering membranes help maintain the concrete's moisture and temperature to ensure its full development of strength and crack resistance. During use, regular monitoring and maintenance can extend the life of the drainage pipe. Regular inspections and repairs of any cracks and damage ensure the pipe's reliability and durability.

[0049] Example 3

[0050] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0051] The cement is PI cement; the sand is medium river sand; the spandex fiber is polyether spandex fiber; and the dispersant is lignin sulfonate dispersant.

[0052] Furthermore, the mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:0.58, where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SF Indicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 3% of the mass of the spandex fiber; the amount of the spandex fiber is m SF Calculated based on the total volume fraction of cement mortar, 0.58% is 1m 3 Add 45kg of spandex fiber to the cement mortar.

[0053] The spandex fiber is a pre-treated spandex fiber material, and the processing method includes the following steps:

[0054] Tearing: Place the spandex fiber on the table, cut it into 30mm long segments with a knife, and then tear it apart with your hands. Pay attention to the strength used to avoid damaging the fiber structure to obtain short spandex fibers.

[0055] Drying: Place the torn short spandex fibers in an oven at 120°C for 1.5 hours to obtain dry short spandex fibers;

[0056] Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator. The electrostatic generator uses high-voltage corona discharge to charge the surface of the spandex with static electricity. The charged spandex fibers are polarized with negative charges under the action of the electrostatic field to obtain treated spandex fibers.

[0057] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0058] The raw materials were weighed according to the ratio, and cement, sand and water were put into a mixer and stirred for 5 minutes. Then, the treated spandex fiber and dispersant were added and the stirring was continued for 15 minutes to obtain cement mortar.

[0059] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0060] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0061] After concrete pipe construction is complete, proper curing is required. Wet curing and covering membranes help maintain the concrete's moisture and temperature to ensure its full development of strength and crack resistance. During use, regular monitoring and maintenance can extend the life of the drainage pipe. Regular inspections and repairs of any cracks and damage ensure the pipe's reliability and durability.

[0062] Example 4

[0063] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0064] The cement is PI cement; the sand is medium river sand; the spandex fiber is polyether spandex fiber; and the dispersant is lignin sulfonate dispersant.

[0065] Furthermore, the mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:0.77, where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SF Indicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 3% of the mass of the spandex fiber; the amount of the spandex fiber is m SF Calculated based on the total volume fraction of cement mortar, 0.77% is 1m 3 Add 60kg of spandex fiber to the cement mortar.

[0066] The spandex fiber is a pre-treated spandex fiber material, and the processing method includes the following steps:

[0067] Tearing: Place the spandex fiber on the table, cut it into 30mm long segments with a knife, and then tear it apart with your hands. Pay attention to the strength used to avoid damaging the fiber structure to obtain short spandex fibers.

[0068] Drying: Place the torn short spandex fibers in an oven at 120°C for 1.5 hours to obtain dry short spandex fibers;

[0069] Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator. The electrostatic generator uses high-voltage corona discharge to charge the surface of the spandex with static electricity. The charged spandex fibers are polarized with negative charges under the action of the electrostatic field to obtain treated spandex fibers.

[0070] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0071] The raw materials were weighed according to the ratio, and cement, sand and water were put into a mixer and stirred for 5 minutes. Then, the treated spandex fiber and dispersant were added and the stirring was continued for 15 minutes to obtain cement mortar.

[0072] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0073] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0074] After concrete pipe construction is complete, proper curing is required. Wet curing and covering membranes help maintain the concrete's moisture and temperature to ensure its full development of strength and crack resistance. During use, regular monitoring and maintenance can extend the life of the drainage pipe. Regular inspections and repairs of any cracks and damage ensure the pipe's reliability and durability.

[0075] Example 5

[0076] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0077] The cement is PI cement; the sand is medium river sand; the spandex fiber is polyether spandex fiber; and the dispersant is lignin sulfonate dispersant.

[0078] Furthermore, the mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:0.96, where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SFIndicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 3% of the mass of the spandex fiber; the amount of the spandex fiber is m SF Calculated based on the total volume fraction of cement mortar, of which 0.96% is 1m 3 Add 75kg of spandex fiber to the cement mortar.

[0079] The spandex fiber is a pre-treated spandex fiber material, and the processing method includes the following steps:

[0080] Tearing: Place the spandex fiber on the table, cut it into 30mm long segments with a knife, and then tear it apart with your hands. Pay attention to the strength used to avoid damaging the fiber structure to obtain short spandex fibers.

[0081] Drying: Place the torn short spandex fibers in an oven at 120°C for 1.5 hours to obtain dry short spandex fibers;

[0082] Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator. The electrostatic generator uses high-voltage corona discharge to charge the surface of the spandex with static electricity. The charged spandex fibers are polarized with negative charges under the action of the electrostatic field to obtain treated spandex fibers.

[0083] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0084] The raw materials were weighed according to the ratio, and cement, sand and water were put into a mixer and stirred for 5 minutes. Then, the treated spandex fiber and dispersant were added and the stirring was continued for 15 minutes to obtain cement mortar.

[0085] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0086] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0087] After concrete pipe construction is complete, proper curing is required. Wet curing and covering membranes help maintain the concrete's moisture and temperature to ensure its full development of strength and crack resistance. During use, regular monitoring and maintenance can extend the life of the drainage pipe. Regular inspections and repairs of any cracks and damage ensure the pipe's reliability and durability.

[0088] Example 6

[0089] A cement mortar for improving crack resistance of a concrete drainage pipe, the cement mortar comprising the following raw material components: cement, sand, water, spandex fiber, and a dispersant;

[0090] The cement is PI cement; the sand is medium river sand; the spandex fiber is polyether spandex fiber; and the dispersant is lignin sulfonate dispersant.

[0091] Furthermore, the mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:1.15, where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SF Indicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 3% of the mass of the spandex fiber; the amount of the spandex fiber is m SF Calculated based on the total volume fraction of cement mortar, 1.15% is 1m 3 Add 90kg of spandex fiber to the cement mortar.

[0092] The spandex fiber is a pre-treated spandex fiber material, and the processing method includes the following steps:

[0093] Tearing: Place the spandex fiber on the table, cut it into 30mm long segments with a knife, and then tear it apart with your hands. Pay attention to the strength used to avoid damaging the fiber structure to obtain short spandex fibers.

[0094] Drying: Place the torn short spandex fibers in an oven at 120°C for 1.5 hours to obtain dry short spandex fibers;

[0095] Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator. The electrostatic generator uses high-voltage corona discharge to charge the surface of the spandex with static electricity. The charged spandex fibers are polarized with negative charges under the action of the electrostatic field to obtain treated spandex fibers.

[0096] A cement mortar for improving the crack resistance of a concrete drainage pipe, wherein the preparation method of the cement mortar comprises the following steps:

[0097] The raw materials were weighed according to the ratio, and cement, sand and water were put into a mixer and stirred for 5 minutes. Then, the treated spandex fiber and dispersant were added and the stirring was continued for 15 minutes to obtain cement mortar.

[0098] A construction process for applying cement mortar to improve the crack resistance of concrete drainage pipes, the construction process comprising the following steps:

[0099] During the construction of the drainage pipe, the prepared cement mortar is poured into the joints of the concrete drainage pipe using construction technology. It is vibrated and compacted at the same time to ensure the tightness and uniformity of the cement mortar concrete and avoid the formation of air holes and cracks.

[0100] After concrete pipe construction is complete, proper curing is required. Wet curing and covering membranes help maintain the concrete's moisture and temperature to ensure its full development of strength and crack resistance. During use, regular monitoring and maintenance can extend the life of the drainage pipe. Regular inspections and repairs of any cracks and damage ensure the pipe's reliability and durability.

[0101] Comparative Example 1

[0102] Compared with Example 1, the difference of Comparative Example 1 is that a dispersant accounting for 0.3% of the total content of the cement mortar is added in Comparative Example 1.

[0103] Comparative Example 2

[0104] Compared with Example 2, the difference of Comparative Example 2 is that the spandex fiber is not pretreated in Comparative Example 2.

[0105] Comparative Example 3

[0106] Compared with Example 2, the difference of Comparative Example 3 is that the polyether spandex fiber is replaced by polyester spandex fiber in Comparative Example 3.

[0107] Comparative Example 4

[0108] Compared with Example 2, the difference of Comparative Example 4 is that no dispersant is added in Comparative Example 4.

[0109] The concrete drainage pipes prepared in Examples 1-6 and Comparative Examples 1-4 were subjected to quality performance tests after curing for one month. Various performance tests were performed on the concrete drainage pipes according to the test standard GB / T50081-2002 "Standard for Test Methods for Mechanical Properties of Ordinary Concrete". All test results are recorded in Table 1 below.

[0110] Table 1 Related performance test results of Examples 1-6 and Comparative Examples 1-4

[0111] Compressive strength / MPa Splitting tensile strength / MPa Whether there are cracks Crack length / cm Example 1 45.2 4.22 have 3.2 Example 2 46.2 4.23 none - Example 3 47.3 4.35 none - Example 4 48.2 4.51 none - Example 5 50.6 4.66 none - Example 6 47.5 4.38 none - Comparative Example 1 45.3 4.21 have 3.0 Comparative Example 2 41.1 4.05 have 3.5 Comparative Example 3 45.1 3.95 have 1.5 Comparative Example 4 42.1 3.82 have 4.2

[0112] As can be seen from Table 1, the crack resistance of the crack-resistant concrete cement mortar prepared in Examples 2-6 is significantly higher than that of the crack-resistant concrete cement mortar prepared in Comparative Examples 1-4 and Example 1. Example 1 does not add spandex cellulose and dispersant, and Comparative Examples 1-4 also selectively add dispersant and spandex fiber. Since the added spandex fiber and dispersant can improve the adhesion between the various materials of the crack-resistant concrete, the generation of cracks in the crack-resistant concrete is suppressed, thereby improving the strength and durability of the crack-resistant concrete prepared by the present invention. It can be seen from the test data of Examples 1-6 that when the amount of spandex fiber added accounts for 0.96% of the cement mortar, the prepared cement mortar has the best performance. Too much or too little spandex fiber content will affect the performance of the cement mortar.

[0113] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A cement mortar for improving the crack resistance of concrete drainage pipes, characterized by: The cement mortar comprises the following raw material components: cement, sand, water, spandex fiber and dispersant; The mass ratio of cement, sand, water and spandex fiber is m c :m s :m w :m SF =1.0:1.5:0.5:m SF , where m c Indicates the cement mass ratio, m s Indicates the proportion of sand mass, m w Indicates the water mass percentage and m SF Indicates the mass ratio of spandex fiber; the content of the dispersant is selected to be 2%-4% of the mass of the spandex fiber; The spandex fiber is a pre-treated spandex fiber material, and the processing method is prepared by the following steps: Tearing: Cut the spandex fiber into small segments of 20-50mm in length, and then tear them apart to obtain short spandex fibers; Drying: Place the torn short spandex fibers in an oven at 100-120°C for 1-2 hours to obtain dry short spandex fibers; Electrostatic treatment: Dry short spandex fibers are passed through an electrostatic generator to impart static electricity to obtain spandex fibers.

2. The cement mortar for improving the crack resistance of concrete drainage pipes according to claim 1, characterized in that: The amount of spandex fiber m SF Calculated according to the total volume fraction of cement mortar, they include 0.39%, 0.58%, 0.77%, 0.96% and 1.15%.

3. The cement mortar for improving the crack resistance of concrete drainage pipes according to claim 2, characterized in that: The amount of spandex fiber m SF Calculated based on the total volume fraction of cement mortar, 0.39% is 1m 3 Add 30kg spandex fiber to cement mortar, 0.58% for 1m 3 Add 45kg spandex fiber to cement mortar, 0.77% for 1m 3 Add 60kg spandex fiber to cement mortar, 0.96% for 1m 3 Add 75kg spandex fiber and 1.15% to 1m 3 Add 90kg of spandex fiber to the cement mortar.

4. The cement mortar for improving the crack resistance of concrete drainage pipes according to claim 3, characterized in that: The spandex fiber includes at least one of polyester spandex fiber and polyether spandex fiber prepared from polyamino polymers or copolymers.

5. The cement mortar for improving the crack resistance of concrete drainage pipes according to claim 1, characterized in that: The cement in the cement mortar includes at least one of P·O cement, P·I cement, P·II cement, P·III cement, P·IV cement and P·V cement.

6. The cement mortar for improving the crack resistance of concrete drainage pipes according to claim 1, characterized in that: The sand in the cement mortar includes at least one of sea sand, river sand and mountain sand.

7. The cement mortar for improving the crack resistance of concrete drainage pipes according to claim 1, characterized in that: The dispersant includes at least one of lignin sulfonate, polycarboxylate, acrylate and polymer emulsion.

8. A method for preparing a cement mortar for improving the crack resistance of a concrete drainage pipe according to any one of claims 1 to 7, characterized in that: The preparation method of the cement mortar comprises the following steps: Weigh the raw materials according to the ratio, put the cement, sand and water into the mixer, stir and mix for 5-10 minutes, then add the treated spandex fiber and dispersant, continue to stir and mix for 10-15 minutes to obtain cement mortar.

9. A method for improving the crack resistance of a concrete drainage pipe, characterized by: During the construction of the drainage pipe, the cement mortar prepared according to claim 8 is poured into the caulking of the concrete drainage pipe and vibrated to compact it while pouring.