A lightweight foamed concrete and a method of making the same

Abstract

The present application relates to a kind of light-weight foam concrete and its preparation method, belong to light-weight concrete technical field, according to weight fraction, its preparation raw material includes: 40-55 parts of Portland cement, 10-15 parts of petroleum pitch, 10-20 parts of river sand, 10-15 parts of foaming agent and 8-16 parts of modified cellulose fiber;Wherein, the modified cellulose fiber is obtained by swelling treatment and steam treatment to cellulose fiber.The internal pressure of closed container is added when steam treatment, the compressive strength, the flexural strength performance of the modified cellulose fiber processed also can increase the light-weight foam concrete prepared, the compressive strength, the flexural strength performance of sample is greatly influenced by using modified cellulose fiber and secondly, the compressive strength, the flexural strength performance of sample is also influenced by adding barium hydroxide in swelling agent, the cellulose fiber after modification has good anti-freezing performance in anti-freezing aspect, can be used in the area of lower temperature.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lightweight concrete, and particularly relates to a lightweight foam concrete and a preparation method thereof. BACKGROUND

[0002] Lightweight concrete, also known as foam concrete, is a new type of lightweight thermal insulation material containing a large number of closed pores, which is formed by fully foaming a foaming agent by a foaming system of a foaming machine, uniformly mixing the foam and a cement slurry, and then performing in-situ construction or mold forming through a pumping system of the foaming machine, and natural curing.

[0003] During the processing of lightweight concrete, cellulose fibers or polypropylene fibers are often added to the lightweight concrete to increase the strength of the lightweight concrete. However, the cellulose fibers or polypropylene fibers located on the outside are prone to degradation after long-term exposure to sunlight, thereby causing the lightweight concrete to gradually fall off from the outside to the inside, and the strength of the lightweight concrete is gradually reduced. SUMMARY

[0004] The present application aims to provide a lightweight foam concrete and a preparation method thereof, which solves the problem that the existing lightweight foam concrete is prone to uneven foaming during use and is prone to breaking.

[0005] The present application achieves the above-mentioned purpose through the following technical solutions:

[0006] A lightweight foam concrete, prepared from the following raw materials in parts by weight: 40-55 parts of Portland cement, 10-15 parts of petroleum pitch, 10-20 parts of river sand, 10-15 parts of a foaming agent, and 8-16 parts of modified cellulose fibers.

[0007] The modified cellulose fibers are obtained by swelling treatment and steam treatment of cellulose fibers.

[0008] Further improvements are made in the preparation steps of the lightweight foam concrete as follows:

[0009] S1. The Portland cement and river sand are weighed according to the weight ratio and placed in a mixer, water is added according to the water-binder ratio of 0.45-0.50, and stirred at 16-20 r / min for 20-30 min to obtain a mixture A;

[0010] S2. The petroleum pitch is added to the mixture A according to the weight ratio, stirred for 10-15 min, the foaming agent is added and continuously stirred until fully mixed to obtain a mixture B;

[0011] S3, taking the cellulose fiber, carrying out swelling treatment and steam treatment to obtain modified cellulose fiber, and adding the modified cellulose fiber into the mixture B according to weight ratio, stirring for 40-60 min to obtain the lightweight foam concrete.

[0012] Further improvement lies in that the swelling treatment refers to immersing the cellulose fiber in a silver ion solution, taking out after 30-45 min, drying, and then stirring in a container with a swelling agent for 5-10 min and taking out for low-temperature drying.

[0013] Further improvement lies in that the steam treatment refers to spraying deionized water on the outside of the cellulose fiber, placing the cellulose fiber in a sealed container, heating at a temperature of 100-120 DEG C for 25-35 min, carrying out 60 kpa pressure treatment on the sealed container at the 10th-12th min of heating, and taking out for drying to obtain the modified cellulose fiber.

[0014] Further improvement lies in that the mass ratio of the cellulose fiber to the swelling agent is 2:3.

[0015] Further improvement lies in that the mass ratio of the deionized water to the cellulose fiber is 1:5.

[0016] Further improvement lies in that, according to weight parts, the preparation raw material of the swelling agent includes 40-50 parts of barium hydroxide, 20-30 parts of montmorillonite powder, 5-10 parts of fructose and 60-80 parts of pure water.

[0017] Further improvement lies in that the preparation method of the swelling agent includes the following steps: first, adding the montmorillonite powder into the pure water to stir to obtain liquid A, then adding the barium hydroxide into the liquid A, stirring until the barium hydroxide is fully melted, then adding the fructose, continuing to stir for 30 min to obtain the swelling agent.

[0018] The beneficial effects of the present application lie in that, by carrying out internal pressure on the sealed container during the steam treatment, the modified cellulose fiber processed can also increase the compressive strength, flexural strength performance of the lightweight foam concrete prepared, the modified cellulose fiber and the sample have great influence on the compressive strength, flexural strength performance and ultraviolet aging anti-splitting tensile strength, and the addition of barium hydroxide in the swelling agent also affects the compressive strength, flexural strength performance and ultraviolet aging anti-splitting tensile strength of the sample. The cellulose fiber modified has good anti-freezing performance in terms of anti-freezing and can be used in areas with lower temperature. DETAILED DESCRIPTION

[0019] The application will be further described in conjunction with the following examples. It is necessary to point out that the following specific embodiments are only used to further illustrate the application and cannot be understood as limiting the scope of protection of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above application content.

[0020] Example 1

[0021] A light-weight foam concrete, the preparation raw materials of which include, by weight fraction: 40 parts of Portland cement, 10 parts of petroleum pitch, 10 parts of river sand, 10 parts of foaming agent and 8 parts of modified cellulose fiber; wherein the modified cellulose fiber is obtained by swelling treatment and steam treatment of cellulose fiber.

[0022] The preparation steps of the light-weight foam concrete are as follows:

[0023] S1, according to the weight ratio, Portland cement and river sand are weighed and placed in a mixer, wherein water is added according to the water-binder ratio of 0.50, and stirred at 16 r / min for 20 min to obtain mixture A;

[0024] S2, according to the weight ratio, petroleum pitch is added to mixture A, stirred for 10 min, 10 parts of foaming agent is added and continue to stir until fully mixed to obtain mixture B;

[0025] S3, take cellulose fiber, swell it and steam it to obtain modified cellulose fiber, and add the modified cellulose fiber to mixture B according to the weight ratio, stir for 40 min to obtain light-weight foam concrete;

[0026] Wherein, the swelling treatment refers to first immersing the cellulose fiber in a silver ion solution, taking it out after 30 min, drying it, and then putting it into a container containing a swelling agent and stirring for 5 min, and then taking it out and drying it at low temperature; the steam treatment refers to first spraying deionized water on the outside of the cellulose fiber, and then placing the cellulose fiber in a sealed container and heating at 100℃ for 25 min, and at the 10th min of heating, the sealed container is subjected to 60kpa pressure treatment, and then taking it out and drying it to obtain modified cellulose fiber; the mass ratio of cellulose fiber to swelling agent is 2:3; the mass ratio of deionized water to cellulose fiber is 1:5;

[0027] The preparation method of the swelling agent includes the following steps: first, 20 parts of montmorillonite powder is added to 70 parts of pure water and stirred to obtain liquid A, then 40 parts of barium hydroxide is added to liquid A, stirred until the barium hydroxide is fully melted, then 5 parts of fructose is added, and continue to stir for 30 min to obtain the swelling agent.

[0028] Example 2

[0029] A light-weight foam concrete, prepared from raw materials including, by weight fraction: 48 parts of Portland cement, 12 parts of petroleum pitch, 15 parts of river sand, 12 parts of foaming agent and 13 parts of modified cellulose fiber; wherein the modified cellulose fiber is obtained by swelling treatment and steam treatment of cellulose fiber.

[0030] The preparation steps of the light-weight foam concrete are as follows:

[0031] S1, Portland cement and river sand are weighed and placed in a mixer, wherein water is added according to a water-binder ratio of 0.50, and stirred at 18 r / min for 25 min to obtain a mixture A;

[0032] S2, petroleum pitch is added to the mixture A according to the weight ratio, stirred for 12 min, and 12 parts of foaming agent is added and continuously stirred until fully mixed to obtain a mixture B;

[0033] S3, cellulose fiber is taken and subjected to swelling treatment and steam treatment to obtain modified cellulose fiber, and the modified cellulose fiber is added to the mixture B according to the weight ratio, and stirred for 50 min to obtain the light-weight foam concrete;

[0034] The swelling treatment refers to first immersing the cellulose fiber in a silver ion solution, taking it out after 35 min, drying, and then stirring in a container containing a swelling agent for 6 min and drying at low temperature; the steam treatment refers to first spraying deionized water on the outside of the cellulose fiber, then placing the cellulose fiber in a sealed container and heating at 110℃ for 30 min, and at the 10th min of heating, the sealed container is subjected to 60kpa pressure treatment, and then dried to obtain the modified cellulose fiber; the mass ratio of cellulose fiber to swelling agent is 2:3; the mass ratio of deionized water to cellulose fiber is 1:5;

[0035] The preparation method of the swelling agent includes the following steps: first, 25 parts of montmorillonite powder is added to 70 parts of pure water and stirred to obtain liquid A, then 45 parts of barium hydroxide is added to the liquid A, stirred until the barium hydroxide is fully melted, then 8 parts of fructose is added, and continuously stirred for 30 min to obtain the swelling agent.

[0036] Example 3

[0037] A light-weight foam concrete, prepared from raw materials including, by weight fraction: 48 parts of Portland cement, 12 parts of petroleum pitch, 15 parts of river sand, 12 parts of foaming agent and 13 parts of modified cellulose fiber; wherein the modified cellulose fiber is obtained by swelling treatment and steam treatment of cellulose fiber.

[0038] The preparation steps of the light-weight foam concrete are as follows:

[0039] S1, according to the weight ratio, the Portland cement and river sand are weighed and placed in a mixer, wherein, according to the water-binder ratio 0.50, water is added, 20r / min stirring 30min, get mixture A;

[0040] S2, according to the weight ratio, petroleum pitch is added to mixture A, stirring 15min, adding 15 parts of foaming agent and continuing to stir until fully mixed, to get mixture B;

[0041] S3, take cellulose fiber, swell treatment and steam treatment, to get modified cellulose fiber, and according to the weight ratio, the modified cellulose fiber is added to mixture B, stirring 60min, to get lightweight foam concrete;

[0042] Wherein, the swelling treatment refers to first using silver ion solution to soak the cellulose fiber, 45min later, drying, then put into the container with swelling agent and stir 10min, take out and dry at low temperature; Steam treatment refers to first spraying deionized water on the outside of cellulose fiber, then put the cellulose fiber into a sealed container and heat at 120℃ for 35min, at the 12th minute of heating, the sealed container is pressurized to 60kpa, take out and dry, to get modified cellulose fiber; The mass ratio of cellulose fiber to swelling agent is 2:3; The mass ratio of deionized water to cellulose fiber is 1:5;

[0043] The preparation method of the swelling agent comprises the following steps: first, 30 parts of montmorillonite powder is added to 80 parts of pure water and stirred to get liquid A, then 50 parts of barium hydroxide is added to liquid A, after the barium hydroxide is fully melted, 10 parts of fructose is added, and after continuing to stir for 30min, the swelling agent is obtained.

[0044] Comparative example 1

[0045] A kind of lightweight foam concrete, according to weight fraction, its preparation raw material includes: 48 parts of Portland cement, 12 parts of petroleum pitch, 15 parts of river sand, 12 parts of foaming agent and 13 parts of cellulose fiber;Wherein, the modified cellulose fiber is obtained by swelling treatment and steam treatment of cellulose fiber.

[0046] The preparation steps of the lightweight foam concrete are as follows:

[0047] S1, according to the weight ratio, the Portland cement and river sand are weighed and placed in a mixer, wherein, according to the water-binder ratio 0.50, water is added, 20r / min stirring 30min, get mixture A;

[0048] S2, according to the weight ratio, petroleum pitch is added to mixture A, stirring 15min, adding 15 parts of foaming agent and continuing to stir until fully mixed, to get mixture B;

[0049] S3, the cellulose fiber is added to the mixture B, and stirred for 50 min to obtain the lightweight foam concrete.

[0050] Comparative Example 2

[0051] A lightweight foam concrete, prepared from the following raw materials in parts by weight: 48 parts of Portland cement, 12 parts of petroleum pitch, 15 parts of river sand, 12 parts of foaming agent and 13 parts of modified cellulose fiber; wherein the modified polypropylene fiber is obtained by swelling treatment and steam treatment of polypropylene fiber.

[0052] The preparation steps of the lightweight foam concrete are as follows:

[0053] S1, the Portland cement and river sand are weighed and placed in a mixer, wherein water is added according to a water-binder ratio of 0.50, and stirred at 18 r / min for 25 min to obtain a mixture A;

[0054] S2, the petroleum pitch is added to the mixture A according to the weight ratio, stirred for 12 min, and then 12 parts of foaming agent is added and stirred until fully mixed to obtain a mixture B;

[0055] S3, the polypropylene fiber is taken and subjected to swelling treatment and steam treatment to obtain modified polypropylene fiber, and the modified polypropylene fiber is added to the mixture B according to the weight ratio, and stirred for 50 min to obtain the lightweight foam concrete;

[0056] The swelling treatment refers to first immersing the polypropylene fiber in a silver ion solution, taking it out after 35 min, drying it, and then placing it in a container containing a swelling agent and stirring for 6 min, and then drying at low temperature; the steam treatment refers to first spraying deionized water on the outside of the polypropylene fiber, and then placing the polypropylene fiber in a sealed container and heating at a temperature of 110℃ for 30 min, and at the 10th min of heating, the sealed container is subjected to a 60kpa pressure treatment, and then dried to obtain the modified polypropylene fiber; the amount ratio between the polypropylene fiber and the swelling agent is 120g:150g; the mass ratio of deionized water to polypropylene fiber is 1:5;

[0057] The preparation method of the swelling agent comprises the following steps: first, 25 parts of montmorillonite powder is added to 70 parts of pure water and stirred to obtain liquid A, then 45 parts of barium hydroxide is added to the liquid A, and stirred until the barium hydroxide is fully melted, then 8 parts of fructose is added, and the mixture is continuously stirred for 30 min to obtain the swelling agent.

[0058] Comparative Example 3

[0059] A kind of light foam concrete, preparation raw material includes by weight ratio: 48 portions of Portland cement, 12 portions of petroleum pitch, 15 portions of river sand, 12 portions of foaming agent and 13 portions of modified cellulose fiber;Wherein, the modified cellulose fiber is obtained by swelling treatment and steam treatment to cellulose fiber.

[0060] The preparation steps of the light foam concrete are as follows:

[0061] S1, according to the weight ratio, Portland cement and river sand are placed in the mixer, wherein, according to the water-binder ratio 0.50, water is added, 18r / min stirring 25min, to obtain mixture A;

[0062] S2, according to the weight ratio, petroleum pitch is added to mixture A, stirring 12min, adding 12 portions of foaming agent and continuing to stir until fully mixed, to obtain mixture B;

[0063] S3, take cellulose fiber, swell treatment and steam treatment are carried out, to obtain modified cellulose fiber, and according to the weight ratio, the modified cellulose fiber is added to mixture B, stirring 50min, to obtain light foam concrete;

[0064] Wherein, swelling treatment refers to first soaking cellulose fiber with silver ion solution, taking out after 35min, drying, and then stirring in a container containing swelling agent for 6min, and drying at low temperature;Steam treatment refers to first spraying deionized water on the outside of cellulose fiber, and then placing the cellulose fiber in a sealed container and heating at 110℃ for 30min, and at the 10th min of heating, the sealed container is subjected to 60kpa pressure treatment, and then drying to obtain modified cellulose fiber;The mass ratio of cellulose fiber to swelling agent is 2:3;The mass ratio of deionized water to cellulose fiber is 1:5;

[0065] The preparation method of the swelling agent includes the following steps: first, 25 portions of montmorillonite powder are added to 70 portions of pure water and stirred to obtain liquid A, then 45 portions of sodium hydroxide are added to liquid A, stirred until the barium hydroxide is fully melted, then 8 portions of fructose are added, and the stirring is continued for 30min to obtain the swelling agent.

[0066] Comparative example 4

[0067] A kind of light foam concrete, preparation raw material includes by weight ratio: 48 portions of Portland cement, 12 portions of petroleum pitch, 15 portions of river sand, 12 portions of foaming agent and 13 portions of modified cellulose fiber;Wherein, the modified cellulose fiber is obtained by swelling treatment and steam treatment to cellulose fiber.

[0068] The preparation steps of the light foam concrete are as follows:

[0069] S1, according to the weight ratio, Portland cement and river sand are taken and placed in a mixer, wherein, according to the water-binder ratio 0.50, water is added, 18 r / min stirring for 25 min, to obtain mixture A;

[0070] S2, according to the weight ratio, petroleum pitch is added to mixture A, stirred for 12 min, 12 parts of foaming agent is added and continue to stir until fully mixed, to obtain mixture B;

[0071] S3, take cellulose fiber, swell treatment and steam treatment to obtain modified cellulose fiber, and according to the weight ratio, the modified cellulose fiber is added to mixture B, stirred for 50 min, to obtain lightweight foam concrete;

[0072] Wherein, the swelling treatment refers to first soaking the cellulose fiber in silver ion solution, taking out after 35 min, drying, and then stirring in a container containing swelling agent for 6 min, and then taking out and drying at low temperature; the steam treatment refers to first spraying deionized water on the outside of the cellulose fiber, and then placing the cellulose fiber in a sealed container and heating at 110℃ for 30 min, and then taking out and drying to obtain modified cellulose fiber; the mass ratio of cellulose fiber to swelling agent is 2:3; the mass ratio of deionized water to cellulose fiber is 1:5;

[0073] The preparation method of the swelling agent comprises the following steps: first, 25 parts of montmorillonite powder is added to 70 parts of pure water and stirred to obtain liquid A, then 45 parts of barium hydroxide is added to liquid A, stirred until the barium hydroxide is fully melted, then 8 parts of fructose is added, and continue to stir for 30 min to obtain the swelling agent.

[0074] Performance test:

[0075] I. Lightweight foam concrete compressive strength test

[0076] The 3d and 28d compressive strength of cement mortar is used to characterize the strengthening and hardening effect of the strengthening and hardening agent. Portland cement (purchased from Wuxi Jianghuai Building Material Technology Co., Ltd.), petroleum pitch (purchased from Henan Derixin New Material Technology Co., Ltd.), foaming agent (purchased from Jinan Qianqi Chemical Co., Ltd.), cellulose fiber (purchased from Wuxi Lvjian Technology Co., Ltd.) and river sand (ISO standard sand) are used for the test. Take the lightweight foam concrete samples prepared in Examples 1-3 and Comparative Examples 1-4, and perform compressive strength and flexural strength performance tests according to "General Portland Cement" GB175-2020; ultraviolet aging detection is performed under the following conditions: ultraviolet aging box (purchased from Suzhou Zhihe Environmental Test Equipment Co., Ltd.), ultraviolet intensity of 210 W / m2, aging temperature of 60℃, aging time of 10d, and the light aging of the lightweight foam concrete samples prepared by using the method of Example 2 and Comparative Examples 1-4 is observed.

[0077] The results are shown in Table 1:

[0078]

[0079] The above data is the average of at least 10 measurements. As can be seen from the above table, among Examples 1-3, the compressive strength and flexural strength performance of Example 2 is the best. Comparing Example 2 with Comparative Example 1, the difference between them is that the cellulose fiber used in Comparative Example 1 is not modified. As can be seen from the above table, the unmodified cellulose fiber has poorer compressive strength and flexural strength performance than Example 2. Comparing Example 2 with Comparative Example 2, the difference between them is that the modified polypropylene fiber used in Comparative Example 2. As can be seen from the above table, at 3 days, the compressive strength and flexural strength performance of Comparative Example 2 is the same as that of Example 2, but at 28 days, the compressive strength and flexural strength performance of the lightweight foam concrete prepared by the method of Comparative Example 2 has decreased. Comparing Example 2 with Comparative Example 3, the difference between them is that the barium hydroxide in the swelling agent of Comparative Example 3 is replaced by sodium hydroxide. As can be seen from the above table, although the values are not much different, the values of Comparative Example 3 are still slightly lower than those of Example 2. Comparing Example 2 with Comparative Example 4, it can be seen that pressurizing the inside of the sealed container during steam treatment can also increase the compressive strength and flexural strength performance of the lightweight foam concrete prepared. In summary, many factors can affect the compressive strength, flexural strength performance and post-ultraviolet aging split tensile strength of the lightweight foam concrete, among which the use of modified cellulose fiber and the compressive strength, flexural strength performance and post-ultraviolet aging split tensile strength of the sample have the greatest impact, followed by the addition of barium hydroxide in the swelling agent, which also affects the compressive strength and flexural strength performance of the sample.

[0080] II. Frost resistance test of lightweight foam concrete

[0081] The lightweight foam concrete samples prepared by the methods of Example 2 and Comparative Examples 1-4 were molded into 40mm x 40mm x 160mm size sample bodies in parallel according to GB / T17671 method, and were cured under standard conditions to 5 age period, then the frost resistance was detected according to T0565-2005 cement concrete frost resistance test method, the freezing time was 30 min each time, and the thawing time was 20 min, and it was observed how many times the lightweight foam concrete sample bodies prepared by the methods of Example 2 and Comparative Examples 1-4 cracked after freezing.

[0082] The results are shown in Table 2:

[0083]

[0084] From the above table, it can be seen that the cellulose fiber after modification has good anti-freezing performance in anti-freezing, and can be used in areas with low temperature. After swelling treatment and steam treatment, the light-weight foam concrete has good anti-freezing effect.

[0085] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the protection scope of the present application.

Claims

1. A lightweight foamed concrete, characterised in that, The preparation raw materials of the lightweight foam concrete include 40-55 parts of silicate cement, 10-15 parts of petroleum pitch, 10-20 parts of river sand, 10-15 parts of foaming agent and 8-16 parts of modified cellulose fiber by weight; The modified cellulose fiber is obtained by swelling treatment and steam treatment of cellulose fiber. The swelling treatment refers to first immersing the cellulose fiber in a silver ion solution, taking it out after 30-45 min, drying, and then stirring in a container containing a swelling agent for 5-10 min and drying at low temperature; the preparation raw materials of the swelling agent include 40-50 parts of barium hydroxide, 20-30 parts of montmorillonite powder, 5-10 parts of fructose and 60-80 parts of pure water by weight; the preparation method of the swelling agent includes the following steps: first, stirring the montmorillonite powder in the pure water to obtain liquid A, then adding barium hydroxide in liquid A, stirring until the barium hydroxide is fully melted, then adding fructose, and continuing to stir for 30 min to obtain the swelling agent; The steam treatment refers to first spraying deionized water on the outside of the cellulose fiber, then placing the cellulose fiber in a sealed container and heating at a temperature of 100-120°C for 25-35 min, and pressurizing the sealed container to 60kpa at the 10th-12th min of heating, then drying to obtain the modified cellulose fiber.

2. A lightweight foamed concrete according to claim 1, characterised in that, The preparation method includes the following steps: S1, the silicate cement and river sand are weighed according to the weight ratio and placed in a mixer, water is added according to the water-binder ratio of 0.45-0.50, and stirred at 16-20 r / min for 20-30 min to obtain mixture A; S2, petroleum pitch is added to mixture A according to the weight ratio, stirred for 10-15 min, foaming agent is added and stirred until fully mixed to obtain mixture B; S3, the cellulose fiber is taken and subjected to swelling treatment and steam treatment to obtain modified cellulose fiber, and the modified cellulose fiber is added to mixture B according to the weight ratio and stirred for 40-60 min to obtain lightweight foam concrete.

3. A lightweight foamed concrete according to claim 1, characterised in that, The mass ratio of the cellulose fiber to the swelling agent is 2:

3.

4. A lightweight foamed concrete according to claim 1, characterised in that, The mass ratio of the deionized water to the cellulose fiber is 1:5.

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