Anti-seepage and anti-crack composite cement mortar as well as preparation method and application thereof

Abstract

The invention discloses anti-seepage and anti-crack composite cement mortar as well as a preparation method and application thereof, and belongs to the technical field of building materials. The anti-seepage and anti-crack composite cement comprises Portland cement, quartz sand, montmorillonite, carbon fibers, styrene butadiene rubber emulsion, a water reducing agent and water. The preparation method comprises the following steps: dissolving a water reducing agent in water to obtain a water reducing agent solution; adding the Portland cement, the quartz sand and the styrene butadiene rubber emulsion into a stirrer for stirring and mixing; then adding montmorillonite and 1 / 2 of the water reducing agent solution, and stirring and mixing; and finally, adding the carbon fibers and the rest 1 / 2 of the water reducing agent solution, and uniformly stirring to obtain the anti-seepage and anti-crack composite cement mortar. The composite cement mortar provided by the invention has excellent anti-seepage and anti-cracking properties, and can reduce the phenomena of cracking and deformation of materials.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to an anti-seepage and anti-cracking composite cement mortar and a preparation method and application thereof. Background Art

[0002] Prestressed concrete cylinder pipe (PCCP) makes full use of the physical and mechanical properties of each material. It has been widely recognized and used in urban water distribution, thermal power plant water supply, water conservancy projects, sewage, industrial water supply and wastewater pipelines. However, domestic hydraulic concrete structures are generally damaged by frost damage, carbonization, erosion, and abrasion, and the surface often has problems such as erosion, shedding, pits, and roughness. At the same time, cement mortar is prone to volume shrinkage during the hydration process, which causes the material to crack and deform, affecting the material's anti-seepage and anti-cracking performance. Therefore, it is urgent to solve the problems of cement mortar cracking and leakage, and develop a new type of cement mortar with high performance, multi-function, green environmental protection and economic benefits. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an anti-seepage and anti-cracking composite cement mortar and a preparation method and application thereof, which has excellent anti-leakage and anti-cracking functions.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] The first aspect of the present invention is to provide an anti-seepage and anti-cracking composite cement mortar, which comprises the following raw materials: silicate cement, quartz sand, montmorillonite, carbon fiber, styrene-butadiene rubber emulsion, a water reducing agent and water.

[0006] In some embodiments, the mass ratio of silicate cement, quartz sand and water is 1-3:4-7:0.5-1.5.

[0007] Preferably, the mass ratio of silicate cement, quartz sand and water is 2:6:1.

[0008] In some embodiments, the amount of styrene-butadiene rubber emulsion is 0.5-5% of the total weight of silicate cement, quartz sand and water; the amount of montmorillonite is 1-10% of the total weight of silicate cement, quartz sand and water; the amount of carbon fiber is 0.1-1% of the total weight of silicate cement, quartz sand and water; and the amount of water reducer is 0.5-2% of silicate cement.

[0009] In some embodiments, the water reducer is selected from at least one of a lignin sulfonate water reducer, a polycyclic aromatic hydrocarbon sulfonate formaldehyde condensation product water reducer, and a polycarboxylate water reducer.

[0010] The second aspect of the present invention is to provide a method for preparing an anti-seepage and anti-cracking composite cement mortar, comprising the following steps:

[0011] S1: dissolving a water reducing agent in water to obtain a water reducing agent solution;

[0012] S2: adding silicate cement, quartz sand and styrene-butadiene rubber emulsion into a mixer and stirring and mixing;

[0013] S3: Add montmorillonite and 1 / 2 water reducing agent solution into the mixed system of S2, and stir to mix;

[0014] S4: Add carbon fiber and the remaining 1 / 2 water reducing agent solution into the mixed system of S3, stir evenly to obtain anti-seepage and anti-cracking composite cement mortar.

[0015] The prepared anti-seepage and anti-cracking composite cement mortar also needs to be loaded into a square mold coated with lubricating oil inside, fully vibrated on a mortar vibration table, and the surface of the mortar is scraped flat with a scraper. After standing for 24 hours, the mold is removed and placed in a standard curing box for curing for 28 days.

[0016] It should be noted that the water reducing agent solution is added in steps with montmorillonite and carbon fiber, which is beneficial to the dispersion of the filler, so that the raw materials are evenly dispersed, which is beneficial to improving the comprehensive performance of the anti-seepage and anti-cracking composite cement mortar.

[0017] In some embodiments, the stirring speed in S2 is 20-40 rpm, and the stirring time is 1-2 min.

[0018] In some embodiments, the stirring speed in S3 is 60-80 rpm, and the stirring time is 4-5 min.

[0019] In some embodiments, the stirring speed in S4 is 60-80 rpm, and the stirring time is 4-5 min.

[0020] Stir at a low speed to pre-mix the materials, and stir at a high speed after adding the functional filler to achieve a uniform dispersion.

[0021] The third aspect of the present invention is to provide an application of an anti-seepage and anti-cracking composite cement mortar in a prestressed steel cylinder concrete pipe.

[0022] The present invention has the following beneficial effects:

[0023] 1. The present invention uses montmorillonite, carbon fiber, and styrene-butadiene rubber latex as functional reinforcing fillers, fully utilizes the advantages of each component, and synergistically modifies the performance of cement mortar. The prepared composite cement mortar has excellent anti-leakage and anti-cracking properties, and can reduce the phenomenon of material cracking and deformation.

[0024] 2. The present invention adds montmorillonite, carbon fiber and styrene-butadiene rubber emulsion. Montmorillonite has good dispersibility and can be evenly dispersed in the mortar matrix to fully fill the pores of the mortar and reduce the porosity of the matrix. In addition, montmorillonite will expand in volume when it meets water to form a thin film colloid, which blocks the pores of the cement mortar and inhibits the entry of water molecules, thereby greatly improving the anti-seepage performance of the cement mortar. Carbon fiber has outstanding characteristics such as high temperature resistance, friction resistance, thermal conductivity and corrosion resistance, and its specific strength and specific modulus are the highest among existing engineering materials. The introduction of carbon fiber can effectively improve the strength and durability of the material, enhance the tensile strength of the mortar, inhibit drying shrinkage, and delay the development of cracks. Styrene-butadiene rubber emulsion has the advantages of anti-slippery, excellent wear resistance, good resilience and small permanent deformation, can effectively reduce the hydrophilic characteristics of cement mortar, and can form bridge chains in the matrix, close pores, enhance the performance of the interface transition zone, etc., thereby enhancing the deformation resistance and fatigue cracking resistance of the cement mortar. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below. The embodiments described are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0026] Example 1

[0027] An anti-seepage and anti-cracking composite cement mortar includes the following raw materials: silicate cement, quartz sand, montmorillonite, carbon fiber, styrene-butadiene rubber emulsion, lignin sulfonate water reducer and water. Among them, the ratio of silicate cement, quartz sand and water is 2:6:1; the amount of styrene-butadiene rubber emulsion is 2% of the total weight of silicate cement, quartz sand and water; the amount of montmorillonite is 8% of the total weight of silicate cement, quartz sand and water; the amount of carbon fiber is 0.8% of the total weight of silicate cement, quartz sand and water; the amount of water reducer is 1% of silicate cement.

[0028] The anti-seepage and anti-cracking composite cement is prepared by the following steps:

[0029] S1: dissolving a water reducing agent in water to obtain a water reducing agent solution;

[0030] S2: Add silicate cement, quartz sand and styrene-butadiene rubber emulsion into a star-type cement mortar mixer and stir at 30 rpm for 1 min;

[0031] S3: Add montmorillonite and 1 / 2 water reducing agent solution into the mixed system of S2 and stir at 70 rpm for 5 min;

[0032] S4: Add carbon fiber and the remaining 1 / 2 water-reducing agent solution into the mixed system of S3, and stir at 70 rpm for 5 minutes to obtain the anti-seepage and anti-cracking composite cement mortar.

[0033] Example 2

[0034] The same as Example 1, the only difference is that the amount of montmorillonite used is 4% of the total weight of silicate cement, quartz sand and water.

[0035] Example 3

[0036] The same as Example 1, the only difference is that the amount of montmorillonite used is 4% of the total weight of silicate cement, quartz sand and water; the amount of carbon fiber used is 0.4% of the total weight of silicate cement, quartz sand and water.

[0037] Example 4

[0038] The same as Example 1, the only difference is that the amount of styrene-butadiene rubber emulsion is 3% of the total weight of silicate cement, quartz sand and water; the amount of montmorillonite is 4% of the total weight of silicate cement, quartz sand and water; the amount of carbon fiber is 0.4% of the total weight of silicate cement, quartz sand and water.

[0039] Comparative Example 1

[0040] The same as Example 4, the difference is only that: no styrene-butadiene rubber latex is added.

[0041] Comparative Example 2

[0042] The same as Example 4, the only difference is that no montmorillonite is added.

[0043] Comparative Example 3

[0044] The same as Example 4, the only difference is that no carbon fiber is added.

[0045] Comparative Example 4

[0046] The same as Example 1, the only difference is: no styrene-butadiene rubber latex, montmorillonite and carbon brazing fiber are added.

[0047] In order to prove that the anti-seepage and anti-cracking composite cement mortar provided by the present invention has excellent anti-leakage and anti-cracking performance, examples 1-4 and comparative examples 1-4 were tested for water retention, compressive strength, flexural strength, anti-seepage performance, and anti-cracking performance. The anti-seepage and anti-cracking composite cement mortar was loaded into a square mold coated with lubricating oil, fully vibrated on a mortar vibrating table, and the mortar surface was scraped flat with a scraper. After standing for 24 hours, the mold was removed and placed in a standard curing box for curing for 28 days. After the curing was completed, the performance test was performed. The test results are summarized in Table 1.

[0048] The following are the performance test standards:

[0049] (1) Test the water retention performance of composite cement mortar according to the provisions of JGJ / T70-2009;

[0050] (2) The compressive strength of composite cement mortar was measured using a pressure testing machine;

[0051] (3) The flexural strength of cement mortar was measured using an electric flexural testing machine;

[0052] (4) Test the anti-permeability of composite cement mortar according to the provisions of TGJ / T70-2009;

[0053] (5) Test the anti-cracking performance of composite cement sand in accordance with the provisions of CECS-13:2009.

[0054] Table 1 Performance test results

[0055]

[0056] From the data in Table 1, it can be seen that compared with the comparative examples, Examples 1-4 have excellent water retention performance, compression and flexural resistance, and high water pressure resistance, and the crack resistance level is all Class I. In Comparative Example 1, no styrene-butadiene rubber emulsion was added, resulting in a decrease in water retention rate, and the crack resistance strength only reached Class II; in Comparative Examples 2 and 3, no montmorillonite and carbon fiber were added, respectively, and the water retention rate and compressive strength decreased to varying degrees, and the crack resistance strength was only Class II, indicating that styrene-butadiene rubber emulsion, montmorillonite and carbon fiber are indispensable, and only by cooperating with each other can the most excellent performance of composite cement be exerted; in Comparative Example 4, no styrene-butadiene rubber emulsion, montmorillonite and carbon fiber were added, and the performance of each index decreased, and the crack resistance only reached Class III, further proving that the addition of styrene-butadiene rubber emulsion, montmorillonite and carbon fiber in the present invention can effectively improve the various properties of composite cement, and the prepared composite cement mortar has excellent anti-leakage and anti-cracking performance, and can reduce the phenomenon of material cracking and deformation.

[0057] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An anti-seepage and anti-cracking composite cement mortar, characterized in that: The anti-seepage and anti-cracking composite cement mortar comprises the following raw materials: silicate cement, quartz sand, montmorillonite, carbon fiber, styrene-butadiene rubber emulsion, a water reducing agent and water.

2. The anti-seepage and anti-cracking composite cement mortar according to claim 1, characterized in that: The mass ratio of the silicate cement, quartz sand and water is 1-3:4-7:0.5-1.

5.

3. The anti-seepage and anti-cracking composite cement mortar according to claim 2 is characterized in that: The amount of the styrene-butadiene rubber emulsion is 0.5-5% of the total weight of silicate cement, quartz sand and water; the amount of the montmorillonite is 1-10% of the total weight of silicate cement, quartz sand and water; the amount of the carbon fiber is 0.1-1% of the total weight of silicate cement, quartz sand and water; and the amount of the water reducer is 0.5-2% of the silicate cement.

4. The anti-seepage and anti-cracking composite cement mortar according to claim 1, characterized in that: The water reducer is selected from at least one of lignin sulfonate water reducer, polycyclic aromatic hydrocarbon sulfonate formaldehyde condensation product water reducer and polycarboxylate water reducer.

5. A method for preparing the anti-seepage and anti-cracking composite cement mortar according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: dissolving a water reducing agent in water to obtain a water reducing agent solution; S2: adding silicate cement, quartz sand and styrene-butadiene rubber emulsion into a mixer and stirring and mixing; S3: Add montmorillonite and 1 / 2 water reducing agent solution into the mixed system of S2, and stir to mix; S4: adding carbon fiber and the remaining 1 / 2 water reducing agent solution into the mixed system of S3, and stirring evenly to obtain the anti-seepage and anti-cracking composite cement mortar.

6. The preparation method according to claim 5, characterized in that: The stirring speed in S2 is 20-40 rpm, and the stirring time is 1-2 min.

7. The preparation method according to claim 5, characterized in that: In the S3, the stirring speed is 60-80 rpm, and the stirring time is 4-5 min.

8. The preparation method according to claim 5, characterized in that: In the S4, the stirring speed is 60-80 rpm and the stirring time is 4-5 min.

9. Use of the anti-seepage and anti-cracking composite cement mortar according to any one of claims 1 to 4 in a prestressed steel cylinder concrete pipe.

Images