阅读说明：本技术 一种混凝土砌块的制备方法及应用 (Preparation method and application of concrete block ) 是由 王传林 刘泽宏 陈锦潮 张碧霞 张德辉 覃杰成 于 2021-06-08 设计创作，主要内容包括：本发明涉及建筑材料技术领域,具体公开了一种混凝土砌块的制备方法及应用,混凝土砌块的制备方法,包括以下步骤：将秸杆加工成段至1-3cm,加入碱性溶液中浸泡,经清洗、烘干后,制得预处理秸杆；取海水、水泥和海砂混合,制得水泥砂浆；将所述预处理秸杆和所述水泥砂浆混合,制得混合料；将所述混合料经成型、养护后,制得混凝土砌块。本发明通过加入秸秆段作为填充材料,既节省了秸秆处理成本,也能在达到非承重结构定位的强度要求的前提,利用更多的秸秆,更具环保价值。同时,通过对秸秆进行预处理,增强了早期的强度,减小了养护时间,在满足作为非承重结构的基本强度要求,也减轻了砌块重量。(The invention relates to the technical field of building materials, and particularly discloses a preparation method and application of a concrete block, wherein the preparation method of the concrete block comprises the following steps: processing straws into segments of 1-3cm, soaking in alkaline solution, cleaning, and oven drying to obtain pretreated straws; mixing seawater, cement and sea sand to prepare cement mortar; mixing the pretreated straws with the cement mortar to prepare a mixture; and forming and curing the mixture to obtain the concrete block. According to the invention, the straw sections are added as filling materials, so that the straw treatment cost is saved, more straws are utilized on the premise of meeting the strength requirement of non-bearing structure positioning, and the environment-friendly value is achieved. Meanwhile, the straw is pretreated, so that the early strength is enhanced, the maintenance time is shortened, the basic strength requirement of a non-bearing structure is met, and the weight of the building block is reduced.)

1. The preparation method of the concrete block is characterized by comprising the following steps:

processing straws into segments of 1-3cm, soaking in alkaline solution, cleaning, and oven drying to obtain pretreated straws;

mixing seawater, cement and sea sand to prepare cement mortar;

mixing the pretreated straws with the cement mortar to prepare a mixture;

and forming and curing the mixture to obtain the concrete block.

2. The method for preparing a concrete block according to claim 1, wherein the mass ratio of the seawater, the cement and the sea sand is (0.25-0.35): 1: 1.

3. the method for preparing the concrete block according to claim 1, wherein the mass ratio of the pretreated straw to the cement mortar is (1-4): 100.

4. the method for preparing a concrete block according to claim 1, wherein said alkaline solution is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

5. The method for producing a concrete block according to claim 1 or 4, wherein the mass concentration of the alkaline solution is 2 to 4%.

6. The method for producing a concrete block according to claim 1, wherein the soaking time is 12 hours or more.

7. The method for preparing a concrete block according to claim 1, wherein the particle size of the sea sand is 30-60 mesh.

8. The method for making a concrete block according to claim 1, wherein said molding is performed using a mold.

9. The method for making a concrete block according to claim 1, wherein said curing step is: firstly, curing for more than 24 hours under the conditions that the temperature is 18-25 ℃ and the humidity is more than 95%; then curing for more than 24 hours at the temperature of 70-80 ℃.

10. Use of a concrete block produced by the method of any one of claims 1 to 9 in the field of construction.

Technical Field

The invention relates to the technical field of building materials, in particular to a preparation method and application of a concrete block.

Background

The building blocks are important materials in engineering construction, and the common building blocks in the market at present are divided into four categories, namely concrete building blocks, fly ash building blocks, gypsum building blocks and composite building blocks. And the traditional concrete block has the defects of heavy mass, high price and the like.

Straw is the general term for the stem and leaf (ear) part of a mature crop, and generally refers to the remaining part of wheat, rice, corn, potatoes, rape, cotton, sugarcane or other crops after harvesting seeds. The straw is an important biological resource, but at present, a lot of straw resources are not fully utilized, and partial areas are treated even by burning, so that not only is the resource wasted, but also the environment is polluted.

In the prior art, the concrete building block is prepared by utilizing straws, the straws are ground into straw ash and then added into the concrete, the preparation process is complex, the breaking strength and the compressive strength of the building block are greatly influenced, and the maintenance time is long.

Disclosure of Invention

The invention provides a preparation method and application of a concrete block, which aims to solve one or more technical problems in the prior art and at least provide a beneficial choice or creation condition.

In order to overcome the technical problems, the technical scheme adopted by the invention is as follows:

a preparation method of a concrete block comprises the following steps:

processing straws into segments of 1-3cm, soaking in alkaline solution, cleaning, and oven drying to obtain pretreated straws;

mixing seawater, cement and sea sand to prepare cement mortar;

mixing the pretreated straws with the cement mortar to prepare a mixture;

and forming and curing the mixture to obtain the concrete block.

In particular, the straw is cut into sections, the cut straw is controlled to be 1-3cm long, and the straw is used as a filling material, so that the processing cost of the straw is saved, more straw can be used on the premise of meeting the strength requirement of a non-bearing structural member, and the straw-cutting and filling material has more environmental protection value.

The straw cut into sections is added into alkaline solution for soaking, the alkaline solution can effectively dissolve a wax layer on the surface of the straw fiber, the wax layer is not beneficial to hydration of cement, the straw soaked by the alkaline solution is beneficial to adhesion of the straw fiber and a concrete matrix, and simultaneously is beneficial to relieving the retardation of the straw to the hydration of the cement, so that the compressive strength and the flexural strength of the concrete block are improved, and the curing time of the concrete block can be shortened.

And cleaning the soaked straws with clear water to remove alkaline solution on the surfaces of the straws, and drying the cleaned straws to finish the pretreatment of the straws.

The main raw materials of the cement mortar are seawater, cement and sea sand, and a water reducing agent is added during mixing, wherein the water reducing agent mainly has the effects of improving the fluidity of concrete, enabling the structure of the concrete to be more stable, improving the strength and simultaneously saving the using amount of the cement under the condition of not changing the strength of the concrete.

Before the seawater is used, the seawater does not need to be desalinated, and the influence of a small amount of chlorine salt in the seawater on a masonry structure is small, so that high desalination cost can be saved. Before the sea sand is used, the sea sand needs to be subjected to vibration screening treatment so as to reduce adverse effects of shells and the like in the sea sand on the compressive strength of concrete.

As a further improvement of the above scheme, the mass ratio of the seawater, the cement and the sea sand is (0.25-0.35): 1: 1. specifically, the basic strength requirement of the concrete block can be ensured by controlling the mass ratio of seawater, cement and sea sand, and the addition of too much or too little seawater is not beneficial to the molding and strength requirements of the concrete.

As a further improvement of the scheme, the mass ratio of the pretreated straws to the cement mortar is (1-4): 100. specifically, the pretreated straws with a proper weight ratio are added, so that the effects of light weight, heat insulation and heat preservation can be achieved while the flexural strength and the compressive strength of the concrete block are ensured.

As a further improvement of the above scheme, the alkaline solution is at least one selected from sodium hydroxide, potassium hydroxide and calcium hydroxide. Specifically, the alkaline solution is preferably a strong alkaline solution, and the straw is soaked by the strong alkaline solution, so that a wax layer on the surface of the straw can be more effectively and completely dissolved, and the bonding of straw fibers and a concrete matrix is facilitated, so that the strength of the brickwork is further improved, and the maintenance time is shortened.

As a further improvement of the above scheme, the concentration of the alkaline solution is 2-4%. Specifically, the alkaline solution with proper concentration is selected, so that the wax layer on the surface of the straw can be removed, and the fiber structure of the straw is not damaged.

As a further improvement of the scheme, the concentration of the alkaline solution is 3.5%, and the soaking time is 12 hours or more. The minimum soaking time is 12 hours, and the sufficient soaking time can ensure that the wax layer on the surface of the straw is completely dissolved.

As a further improvement of the scheme, the particle size of the sea sand is 30-60 meshes. Specifically, the average particle size of the sea sand is finer than that of river sand, but the sea sand often contains a small amount of shells, so that the sea sand needs to be subjected to a vibrating screen treatment before use, and the sea sand can pass through a 30-60-mesh screen.

As a further improvement of the scheme, the mixture is molded by a mold. Specifically, a mould is selected, a layer of lubricating oil is brushed on the inner wall of the mould to prevent the concrete from being adhered to the inner wall of the mould, the mixed straw concrete mixture is filled into the mould, and the mixture is vibrated and the surface is smoothed to be uniformly mixed.

As a further improvement of the above scheme, the step of maintaining comprises: firstly, curing for more than 24 hours under the conditions that the temperature is 18-25 ℃ and the humidity is more than 95%; then curing for more than 24 hours at the high temperature of 70-80 ℃.

The invention also provides a technical scheme that the concrete block prepared by the preparation method of the concrete block is applied to the field of buildings. The non-bearing wall is particularly suitable for being applied to building non-bearing walls, the non-bearing walls do not contain reinforcing steel bars, the influence on chlorine salt and sea sand fine particles is small, the sea sand is treated, the adverse influence of impurities such as shells in the sea sand on the strength of concrete is reduced, and the requirements on the strength and the durability of concrete blocks are met.

The technical scheme provided by the embodiment of the application at least has the following technical effects or advantages:

the invention reasonably utilizes the straw resources and the seawater and sea sand resources, the straw materials are easy to obtain, and the cost is low; the sea water and sea sand are rich in resources, and the adverse effects of chloride salt, shells and the like in the sea sand on the concrete are reduced through the purification treatment of the sea sand, so that the available standard is reached, and the strength, the durability and the like of the concrete building block are ensured.

Compared with the prior art that the strength is greatly reduced by grinding the straws into ash to replace partial cement and additives, the invention saves the straw treatment cost by taking the straws which are cut into 1-3cm as the filling material, and can add more straws on the premise of meeting the strength requirement of non-bearing structural members, thereby having more environmental protection value. Meanwhile, the straws are soaked in the alkaline solution, so that the influence of the straws on the hydration reaction of the mixture is reduced, the early strength of the concrete is enhanced, and the curing time is shortened. The concrete block prepared by the invention can meet the basic strength requirement of a non-bearing structure, also achieves the purposes of reducing the weight of the block and has certain sound and heat insulation effects.

Detailed Description

The present invention is described in detail below by way of examples to facilitate understanding of the present invention by those skilled in the art, and it is to be specifically noted that the examples are provided only for the purpose of further illustrating the present invention and are not to be construed as limiting the scope of the present invention.

Example 1

A concrete block is composed of the following materials: 0.75kg of Portland cement, 0.75kg of sea sand, 0.1655kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (the solid content is 15%), 0.02kg of straw mixing amount and 0.28 of water-cement ratio.

A preparation method of a concrete block comprises the following steps:

processing straws into segments of 1cm, soaking the straws in a sodium hydroxide solution with the mass fraction of 2% for 48 hours, washing the straws with clear water, placing the straws in an oven for drying at 75 ℃, taking out the straws after 48 hours, and cooling to obtain pretreated straws;

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the prepared pretreated straws with cement mortar, and uniformly stirring to prepare a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 24 hours under the conditions that the temperature is 20 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 70 ℃ for curing for 24 hours. And taking out the sample and cooling to obtain the concrete block.

Example 2

A concrete block is composed of the following materials: 0.75kg of Portland cement, 0.75kg of sea sand, 0.143kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (the solid content is 15%), 0.03kg of straw doping amount and 0.25 of water-cement ratio.

A preparation method of a concrete block comprises the following steps:

processing straws into segments of 1cm, soaking the straws in a potassium hydroxide solution with the mass fraction of 4% for 24 hours, washing the straws with clear water, placing the straws in an oven for drying at 80 ℃, taking out the straws after 36 hours, and cooling to obtain pretreated straws;

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the prepared pretreated straws with cement mortar, and uniformly stirring to prepare a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 24 hours under the conditions that the temperature is 25 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 75 ℃ for curing for 24 hours. And taking out the sample and cooling to obtain the concrete block.

Example 3

A concrete block is composed of the following materials: 0.75kg of Portland cement, 0.75kg of sea sand, 0.2105kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (the solid content is 15%), 0.02kg of straw mixing amount (soaking by using NaOH solution with the mass fraction of 4% and then drying), and the water-glue ratio is 0.34.

A preparation method of a concrete block comprises the following steps:

processing straws into segments of 1cm, soaking the straws in a calcium hydroxide solution with the mass fraction of 3% for 36h, washing the straws with clear water, placing the straws in an oven for drying at 75 ℃, taking out the straws after 24h, and cooling to obtain pretreated straws;

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the prepared pretreated straws with cement mortar, and uniformly stirring to prepare a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 24 hours under the conditions that the temperature is 20 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 70 ℃ for curing for 24 hours. And taking out the sample and cooling to obtain the concrete block.

Comparative example 1

A concrete block is composed of the following materials: 0.75kg of Portland cement, 0.75kg of sea sand, 0.143kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (the solid content is 15%), 0.03kg of straw doping amount and 0.25 of water-cement ratio.

A preparation method of a concrete block comprises the following steps:

processing the straws into segments of 1cm to prepare pretreated straws;

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the prepared pretreated straws with cement mortar, and uniformly stirring to prepare a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 24 hours under the conditions that the temperature is 20 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 70 ℃ for curing for 24 hours. And taking out the sample and cooling to obtain the concrete block.

The comparative example differs from example 2 in that the straw was only cut into pieces and not soaked in an alkaline solution.

Comparative example 2

A seawater sea sand straw concrete block is composed of the following materials: 0.75kg of ordinary portland cement, 0.75kg of sea sand, 0.21kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (with the solid content of 15%), 0.04kg of straw powder and 0.34 of water-cement ratio.

A preparation method of a concrete block comprises the following steps:

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the straw powder and the cement mortar, and uniformly stirring to obtain a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 24 hours under the conditions that the temperature is 20 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 70 ℃ for curing for 48 hours. And taking out the sample and cooling to obtain the concrete block.

The biggest difference between this comparative example and example 2 is that the straw was processed into powder and added as a filler.

Comparative example 3

A concrete block is composed of the following materials: 0.75kg of Portland cement, 0.75kg of sea sand, 0.15kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (the solid content is 15%), 0.025kg of straw (the straw is soaked by NaOH solution with the mass fraction of 4% and then dried), and the water-to-glue ratio is 0.25.

A preparation method of a concrete block comprises the following steps:

processing straws into segments of 0.5cm, soaking the straws in a calcium hydroxide solution with the mass fraction of 3% for 28h, washing the straws with clear water, placing the straws in an oven for drying at 75 ℃, taking out the straws after 24h, and cooling the straws to obtain pretreated straws;

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the prepared pretreated straws with cement mortar, and uniformly stirring to prepare a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 28 hours under the conditions that the temperature is 20 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 70 ℃ for curing for 30 hours. And taking out the sample and cooling to obtain the concrete block.

The comparative example differs from example 2 in that the straw was processed into segments of up to 0.5cm

Comparative example 4

A concrete block is composed of the following materials: 0.75kg of Portland cement, 0.75kg of sea sand, 0.15kg of seawater, 0.053kg of polycarboxylic acid water reducing agent (the solid content is 15%), 0.025kg of straw (the straw is soaked by NaOH solution with the mass fraction of 4% and then dried), and the water-to-glue ratio is 0.25.

A preparation method of a concrete block comprises the following steps:

processing straws into segments of 2cm, soaking the straws in a sodium hydroxide solution with the mass fraction of 4% for 18h, washing the straws with clear water, placing the straws in an oven for drying at 75 ℃, taking out the straws after 28h, and cooling the straws to obtain pretreated straws;

uniformly mixing the weighed Portland cement and sea sand, adding the sea water and the polycarboxylic acid water reducing agent, and fully stirring to prepare cement mortar;

mixing the prepared pretreated straws with cement mortar, and uniformly stirring to prepare a mixture;

and putting the mixture into a mould with the size of 40mm multiplied by 160mm, vibrating, smoothing the surface, forming, curing for 20 hours under the conditions that the temperature is 20 ℃ and the humidity is 96%, removing the mould, and placing in an oven with the temperature of 70 ℃ for curing for 31 hours. And taking out the sample and cooling to obtain the concrete block.

The difference between the comparative example and the example 2 is that the straw is processed into 2cm sections

Performance testing

The concrete blocks obtained in the examples and comparative examples were weighed to calculate the dry density, and the flexural strength and compressive strength were measured according to the Cement mortar Strength test method (GB/T17671-1999). The dry density, measured flexural strength and compressive strength values of each example and comparative example are shown in table 1 below.

TABLE 1 comparison of concrete Performance parameters obtained in examples and comparative examples

From the performance parameters of the concrete blocks produced in the examples and comparative examples of table 1, it can be seen that: examples 1 and 2 well demonstrate that the flexural and compressive strengths of concrete made using straw fiber treated with a strong alkaline solution are significantly better than the sea sand straw concrete made from untreated straw. In the embodiment 3, the dry density of the building block is smaller due to the relatively larger water-cement ratio, but the flexural and compressive strength of the building block is lower than that of the building blocks in the embodiments 1 and 2, and the strength requirement of a non-load-bearing structure can still be met. Comparative example 1 because the straw fiber is not pretreated, the experimental strength is obviously reduced compared with that of example 1, but the requirement of breaking and compression strength can be basically met. Comparative example 2 is the biggest reason for its failure to meet the non-load bearing strength rating due to the addition of straw powder instead of straw fiber. Comparative examples 3 and 4 show that the compressive strength of the building block can be satisfied by changing the length of the straw within a certain range, but the compressive strength is reduced compared with that of the straw processed into segments of 1 cm.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are intended to be within the scope of the invention.