Fair-faced concrete admixture and preparation method thereof

Abstract

The invention belongs to the technical field of concrete admixtures, and particularly relates to a fair-faced concrete admixture which is prepared by mixing the following raw materials: a water reducing agent, mother liquor, a slump retaining agent, a retarder and a defoaming agent, wherein the admixture comprises the following components in parts by weight: 2-4 parts of a water reducing agent; 3-6 parts of the mother liquor; 2-3 parts of a slump retaining agent; 2 to 3 parts of a retarder; the content of the defoaming agent is 0.05 to 0.15 part; the invention also provides a preparation method of the fair-faced concrete admixture, and the preparation method comprises the following steps: uniformly mixing the components according to the required parts for 5-10 minutes to obtain the admixture. Fully stirring and uniformly mixing the prepared admixture with the bare concrete, wherein the doping amount of the admixture is 2-2.7% of the weight of the bare concrete; the admixture can effectively control the air hole amount of the surface of the bare concrete, and the appearance of the surface of the bare concrete is guaranteed; meanwhile, the viscosity and fluidity of the bare concrete are improved, and the expansion degree of the bare concrete is kept.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete admixtures, and particularly relates to a plain concrete admixture and a preparation method thereof. Background Art

[0002] Concrete admixture refers to a substance added to improve the performance of concrete before or during the mixing process of concrete. Concrete admixture has an important influence on certain properties of concrete. In the production of plain concrete, it is necessary to control the appearance of concrete and reduce the appearance defects of concrete after hardening as much as possible. The core point is to overcome the bubble problem after the plain concrete hardens and avoid the appearance of a large number of pores on the concrete surface. At the same time, it is necessary to consider the workability, viscosity and expansion of plain concrete. Therefore, a plain concrete admixture and a preparation method thereof are proposed. Summary of the invention

[0003] The purpose of the present invention is to provide a plain concrete admixture and a preparation method thereof, so as to solve the problems existing in the background technology.

[0004] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0005] A plain concrete admixture is prepared by mixing the following raw materials:

[0006] Water reducing agent, mother liquor, collapse retaining agent, retarder and defoaming agent;

[0007] Wherein, the components of the admixture include by weight:

[0008] 2-4 parts of the water reducing agent;

[0009] 3-6 parts of the mother liquor, wherein the mother liquor comprises a viscosity reducer and a workability improver;

[0010] 2-3 parts of the collapse-preserving agent;

[0011] 2-3 parts of the retarder, which includes sodium glucose and sucrose;

[0012] The defoaming agent is 0.05-0.15 parts.

[0013] The admixture of the present invention, wherein the viscosity reducer and the workability improver can effectively reduce the viscosity of the clear water concrete, improve the workability of the clear water concrete, make the pores in the clear water concrete easily discharged, cooperate with the defoamer component in the admixture to eliminate the discharged bubbles, thereby effectively controlling the amount of pores on the surface of the clear water concrete and ensuring the appearance of the surface of the clear water concrete; the admixture does not use an air entraining agent, cooperates with the viscosity reducer component in the admixture to improve the viscosity and fluidity of the clear water concrete, and at the same time, considering that the bleeding and segregation of the clear water concrete affect the appearance of the clear water concrete, cooperates with the slump retaining agent component in the admixture to effectively maintain the expansion of the clear water concrete, and through the retarder component in the admixture, effectively controls the setting time of the clear water concrete.

[0014] The viscosity reducer is 1-3 parts, and the workability improver is 1-5 parts.

[0015] The defoamer is any one of a silicone defoamer or a polyether acetylene glycol defoamer. From the test results of the air content of the plain concrete and the comprehensive analysis of the appearance of the plain concrete after hardening, the polyether acetylene glycol defoamer has a better defoaming effect and fewer bubbles in the appearance of the plain concrete after hardening, so the polyether acetylene glycol defoamer is preferably used.

[0016] The sodium glucose content is 1.5-3 parts, and the sucrose content is 0-0.7 parts.

[0017] The components of the admixture include by weight:

[0018] 3 parts of water reducing agent;

[0019] 3 parts of viscosity reducer;

[0020] 3 parts of workability improver;

[0021] 2 parts of collapse-preventing agent;

[0022] Defoaming agent 0.1 part;

[0023] 2.7 parts of retarder, including 0.7 parts of sucrose and 2 parts of sodium glucose.

[0024] Based on the above technical solution, the present invention provides a method for preparing a plain concrete admixture, the preparation method comprising:

[0025] ① Evenly mix the components in the required number for 5-10 minutes to obtain the admixture;

[0026] ② The prepared admixture is fully stirred and mixed with the plain concrete, and the admixture dosage is 2-2.7% of the weight component of the plain concrete.

[0027] The beneficial effects of the present invention are:

[0028] ① Viscosity reducer and workability improver can effectively reduce the viscosity of plain concrete, improve the workability of plain concrete, make the pores in plain concrete easy to discharge, and cooperate with the defoamer in the admixture to eliminate the discharged bubbles, so as to effectively control the pore volume on the surface of plain concrete and ensure the appearance of the surface of plain concrete;

[0029] ② The viscosity reducer in the admixture improves the viscosity and fluidity of the plain concrete. At the same time, taking into account the bleeding and segregation of plain concrete that affect its appearance, the slump retaining agent in the admixture is added to effectively maintain the expansion of the plain concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further illustrated by means of the non-limiting examples given in the accompanying drawings.

[0031] Figure 1 This is a schematic diagram of the hardened appearance of plain concrete at various dosages of organosilicon defoamers;

[0032] Figure 2 This is a schematic diagram of the hardened appearance of plain concrete with various dosages of polyether acetylene glycol defoamers;

[0033] Figure 3 This is a schematic diagram of the appearance of the plain concrete after demoulding in the viscosity reduction mother solution control test;

[0034] Figure 4 This is a schematic diagram of the appearance of plain concrete with different admixture dosages;

[0035] Figure 5 Schematic diagram of the hardened appearance after adding admixtures with the optimal component ratio into the plain concrete using a flexural test mold. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0037] A plain concrete admixture is prepared by mixing the following raw materials:

[0038] Water reducing agent, mother liquor, collapse retaining agent, retarder and defoaming agent;

[0039] Among them, the components of the admixture include by weight:

[0040] 2-4 parts of water reducing agent;

[0041] 3-6 parts of mother liquor; the mother liquor includes a viscosity reducer and a workability improver, wherein the viscosity reducer is 1-3 parts and the workability improver is 1-5 parts;

[0042] 2-3 parts of collapse-preventing agent;

[0043] 2-3 parts of retarder; the retarder includes sodium glucose and sucrose, wherein the sodium glucose is 1.5-3 parts and the sucrose is 0-0.7 parts.

[0044] 0.05-0.15 parts of defoaming agent; the defoaming agent is any one of silicone defoaming agent or polyether acetylene glycol defoaming agent.

[0045] The admixture, viscosity reducer and workability improver of the invention can effectively reduce the viscosity of the plain concrete, improve the workability of the plain concrete, make the pores in the plain concrete easily discharged, and eliminate the discharged bubbles by cooperating with the defoamer component in the admixture, so as to effectively control the amount of pores on the surface of the plain concrete and ensure the appearance of the surface of the plain concrete; the admixture does not use an air entraining agent, and the viscosity reducer component in the admixture is used to improve the viscosity and fluidity of the plain concrete, and at the same time, considering that the bleeding and segregation of the plain concrete affect the appearance of the plain concrete, the collapse preventing agent component in the admixture is added to effectively maintain the expansion degree of the plain concrete, and the retarder component in the admixture is used to effectively control the setting time of the plain concrete.

[0046] Based on the above technical solution, the present invention provides a method for preparing a clear water concrete admixture, the preparation method comprising:

[0047] ① Evenly mix the components in the required number for 5-10 minutes to obtain the admixture;

[0048] ② The prepared admixture is fully stirred and mixed with the plain concrete, and the admixture dosage is 2-2.7% of the weight component of the plain concrete.

[0049] It should be noted that the components of the admixture in the present invention adopt the following specifications:

[0050] Serial number Components Specifications 1 Water reducing agent NJ400 2 Viscosity reducer PC-1 type 3 Workability Improver PT-E type 4 Collapse inhibitor PT6407 5 Defoaming agent Model 912Z

[0051] in:

[0052] According to GB80796-2008 and GB8077-2012, the technical requirements for water reducers are as follows:

[0053] Solid content 50% ± 0.5, density 1.099 ± 0.005, pH value 5.0 ± 1;

[0054] According to GB8076-2008, the technical requirements for viscosity reducers are as follows:

[0055] Solid content 35%*(1±5%), PH value 6.0±1.5, density 1.08±0.01g / cm 3 , water reduction rate ≥ 25%;

[0056] According to GB8076-2008, the technical requirements for PT-E type workability improver are as follows:

[0057] Water reduction rate ≥25%, air content ≤6%, water bleeding ratio ≤60%, shrinkage ratio ≤110%, chloride ion content ≤0.6%, sodium sulfate content ≤5%, solid content 49%±2.45, density 1.098±0.02g / cm 3 , pH value 6.0±2.0;

[0058] According to GB8076-2008 and JC / T2481-2018, the technical requirements for collapse inhibitors are as follows:

[0059] 1h gas content ≤6%, chloride ion content ≤0.6%, sodium sulfate ≤5%, alkali content ≤10%, solid content 48%±2.4, density 1.094±0.02g / cm 3 , pH value 6.0±2.0;

[0060] The technical requirements for defoamers are as follows:

[0061] PH value 6.0-7.5, moisture content <1%, density 0.85-1.05g / cm 3 , the viscosity at room temperature 25℃ is 200-450mPa·S.

[0062] Embodiment 1:

[0063] Selection and proportion test of workability improver:

[0064] Taking into account the high requirements for workability of plain concrete, and the increase in the dosage of plain concrete admixtures, the insensitivity of concrete, and the strong resistance to segregation, an E-type workability improver (referred to as "E-type mother liquor" in this embodiment) is selected. The characteristics of the E-type mother liquor are rich concrete slurry, and the concrete is not easy to segregate and bleed, but the water reduction rate is low, and the mortar water reduction rate is 15%, which is suitable for use in winter. The concrete loss is large when used in summer.

[0065] Comparative test:

[0066] 1# admixture ratio: 6% water reducing agent, 3% slump retaining agent, 3% sodium gluconate, 0.06% air entraining agent, 0.02% defoaming agent;

[0067] 2# admixture ratio: 3% water reducing agent, 3% E-type mother liquor, 3% collapse retaining agent, 3% sodium gluconate, 0.06% air entraining agent, 0.02% defoaming agent;

[0068] In this embodiment, the difference between the 1# admixture ratio and the 2# admixture ratio is that 6% of the water reducing agent is replaced by 3% of the water reducing agent plus 3% of the mother liquor.

[0069] The test results are shown in the following table:

[0070]

[0071]

[0072] From the above we can see that:

[0073] In the 2# admixture ratio, after using E-type mother liquor, the working width of the concrete admixture is significantly improved. With the increase of the admixture dosage, the expansion of the concrete gradually increases, the slurry is rich, but the concrete has good workability and does not segregate. Therefore, it is preferred to determine the ratio of E-type mother liquor in the admixture to be 3%.

[0074] Embodiment 2:

[0075] Defoamer selection and ratio test:

[0076] Admixture ratio: 6% water reducing agent, 3% E-type mother liquor, 2% slump retaining agent, 1.5% sodium gluconate.

[0077] The test results are shown in the following table:

[0078]

[0079] ①From the experimental results of gas content, we can know that:

[0080] Polyether acetylene glycol defoamers have better defoaming effects than silicone defoamers;

[0081] ② From the appearance of the hardened plain concrete, we can see that:

[0082] When using polyether acetylene glycol defoamers, the surface bubbles of plain concrete are minimal.

[0083] In summary, it is decided to use polyether acetylene glycol defoamers. At the same time, it can be noted that with the increase in the amount of defoamer, the bubbles on the surface of the hardened concrete gradually decrease, but the air content of the concrete does not decrease significantly. The main reason is that there is no positive proportional relationship between the air content of the concrete and the amount of defoamer. Excessive defoamer will seriously affect the viscosity and fluidity of the concrete. Considering the construction performance of plain concrete, it is preferred to determine the ratio of the defoamer to be 0.1%.

[0084] Embodiment 3:

[0085] Selection and proportion test of viscosity reducer:

[0086] 1. Test object: C60 concrete;

[0087] Admixture ratio:

[0088] 1# admixture ratio (without viscosity reducer): 9% water reducer, 1.5% collapse retainer, 3% sodium gluconate, 0.04% air entraining agent, 0.02% defoamer;

[0089] 2# admixture ratio: 6% water reducer, 3% viscosity reducer, 1.5% collapse retainer, 3% sodium gluconate, 0.04% air entraining agent, 0.02% defoamer;

[0090] In this embodiment, the difference between the 1# admixture ratio and the 2# admixture ratio is that 9% of the water reducing agent is replaced by 6% of the water reducing agent plus 3% of the viscosity reducing agent.

[0091] The results of the C60 concrete viscosity reduction test are as follows:

[0092]

[0093] From the test results, it can be seen that the viscosity reducer can reduce the viscosity of C60 concrete, but the water reduction rate of the viscosity reducer is low.

[0094] 2. Test object: C40P8 plain concrete;

[0095] Admixture ratio:

[0096] 1# admixture ratio (without viscosity reducer): 6% water reducer, 3% E-type mother liquor, 2% collapse retainer, 1.5% sodium gluconate, 0.1% defoamer;

[0097] 2# admixture ratio: 5% water reducing agent, 1% E-type mother liquor, 3% viscosity reducer, 2% collapse retaining agent, 1.5% sodium gluconate, 0.1% defoaming agent;

[0098] In this embodiment, the difference between the 1# admixture ratio and the 2# admixture ratio is that 6% of the water reducer is replaced by 5% of the water reducer plus 1% of the E-type mother liquor, and 3% of the viscosity reducer is added.

[0099] The appearance of the exposed concrete after demoulding is as follows Figure 3 As shown, it can be clearly seen that after adding the viscosity reducing mother liquor, the bubbles on the concrete surface are significantly reduced. The main reason is that the addition of the viscosity reducing mother liquor reduces the surface tension of the concrete, and the concrete bubbles are easier to discharge. Therefore, the viscosity reducer can reduce the viscosity of high-grade concrete, significantly improve the appearance of concrete in plain concrete, and reduce the generation of large bubbles on the surface of plain concrete. The preferred ratio of the viscosity reducer is 3%.

[0100] Embodiment 4:

[0101] Test on the influence of concrete expansion on the appearance of plain concrete:

[0102] The working width of the admixture for plain concrete must be large, and the concrete cannot be too sensitive, otherwise it will easily lead to water bleeding and segregation of the concrete, affecting the appearance of the plain concrete. Therefore, the expansion of concrete is mainly maintained by increasing the dosage of admixtures, and the dosage of the collapse-preserving mother liquid should be as low as possible;

[0103] Admixture ratio: 2.0% collapse-preventing agent, 5% E-type mother liquor, 1.0% viscosity reducer, 0.1% defoamer, 3% sodium gluconate;

[0104] Three control test groups were set for the admixture dosage, namely 2%, 2.2% and 2.6%;

[0105] The test results are shown in the following table:

[0106]

[0107] Through experiments, we know that if the expansion of concrete is too small, the concrete will not be vibrated solidly during molding. Even if the vibration time is extended, large air pores will easily form on the concrete surface. If the expansion of concrete is too large, water marks will form on the concrete surface after vibration, which will easily cause the concrete stones to sink and the slurry to float. Some plain concrete test blocks will have a thin layer of cement shell on the surface, which will fall off at the touch of a button, and large air pores will appear on the concrete surface. Therefore, the air content of plain concrete is best controlled at 2.0%, and the expansion degree should be controlled at 450-500mm during concrete pouring. It is preferred to determine the dosage of admixture at 2.0-2.4%.

[0108] Embodiment 5:

[0109] Based on the experimental verification of the above embodiments, the components of the preferred admixture include by weight:

[0110] 3 parts of water reducing agent;

[0111] 3 parts of viscosity reducer;

[0112] 3 parts of workability improver;

[0113] 2 parts of collapse-preventing agent;

[0114] Defoaming agent 0.1 part;

[0115] 2.7 parts of retarder, including 0.7 parts of sucrose and 2 parts of sodium glucose.

[0116] The final proportion of the preferred plain concrete admixture is:

[0117] 3% water reducing agent, 3% viscosity reducing agent, 3% workability improving agent (E-type mother solution), 2% slump retaining agent, 0.1% defoaming agent and 2.7 retarder (2% sodium glucose + 0.7% sucrose) were used for forming using a flexural test mold. The test results are as follows Figure 5As shown, after the fair-faced concrete hardens, there are few bubbles on the surface and the color is more uniform.

[0118] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A plain concrete admixture, characterized in that: The composition is made from the following raw materials: Water reducing agent, mother liquor, collapse retaining agent, retarder and defoaming agent; Wherein, the components of the admixture include by weight: 2-4 parts of the water reducing agent; 3-6 parts of the mother liquor, wherein the mother liquor comprises a viscosity reducer and a workability improver; 2-3 parts of the collapse-preserving agent; 2-3 parts of the retarder, which includes sodium glucose and sucrose; The defoaming agent is 0.05-0.15 parts.

2. A plain concrete admixture according to claim 1, characterized in that: The viscosity reducer is 1-3 parts, and the workability improver is 1-5 parts.

3. A clear water concrete admixture according to claim 2, characterized in that: The defoamer is any one of an organosilicon defoamer or a polyether acetylene glycol defoamer.

4. A plain concrete admixture according to claim 3, characterized in that: The sodium glucose content is 1.5-3 parts, and the sucrose content is 0-0.7 parts.

5. A plain concrete admixture according to claim 4, characterized in that: The components of the admixture include by weight: 3 parts of water reducing agent; 3 parts of viscosity reducer; 3 parts of workability improver; 2 parts of collapse-preventing agent; Defoaming agent 0.1 part; 2.7 parts of retarder, including 0.7 parts of sucrose and 2 parts of sodium glucose.

6. A method for preparing a plain concrete admixture, comprising the plain concrete admixture according to any one of claims 1 to 5, characterized in that: The preparation method comprises: ① Evenly mix the components in the required number for 5-10 minutes to obtain the admixture; ② The prepared admixture is fully stirred and mixed with the plain concrete, and the admixture dosage is 2-2.7% of the weight component of the plain concrete.

Images