阅读说明：本技术 一种混凝土控泡剂的性能测试评价方法 (Performance test evaluation method of concrete foam control agent ) 是由 王永定 邱岳涛 陈周鹏 胡俊华 彭合堂 林添兴 郭元强 于 2020-11-26 设计创作，主要内容包括：本发明涉及混凝土控泡剂技术领域,特别涉及一种混凝土控泡剂的性能测试评价方法,通过测试在混凝土控泡剂的作用下的新拌混凝土的初始扩展度、堆积高度、初始含气量、表观气泡量、浮浆质量和常压泌水率,并基于此测试评价混凝土中的控泡剂的控泡性能是否能够满足混凝土的施工性、表观及耐久性要求。该测试评价方法简便易行,验证可靠,利于评价分析掺入控泡剂的新拌混凝土的和易性及施工性的变化,也利于有效筛选出优质的控泡剂,降低因劣质控泡剂作用下导致的混凝凝土施工性能的缺失及其他性能的缺失,提高混凝土的工程质量,利于混凝土施工效率及综合效益的提升。(The invention relates to the technical field of concrete foam control agents, in particular to a performance test and evaluation method of a concrete foam control agent. The test evaluation method is simple and easy to implement, is reliable in verification, is beneficial to evaluating and analyzing the workability and the change of the constructability of the fresh concrete doped with the foam control agent, is also beneficial to effectively screening the foam control agent with high quality, reduces the loss of the construction performance and other performance of the concrete caused by the action of the foam control agent with poor quality, improves the engineering quality of the concrete, and is beneficial to improving the construction efficiency and the comprehensive benefit of the concrete.)

1. A performance test evaluation method of a concrete foam control agent is characterized by comprising the following steps:

s100, testing concrete mixture indexes of fresh concrete under the action of a reference and a detected foam control agent, wherein the concrete mixture indexes comprise initial expansion degree, stacking height, initial gas content, apparent bubble content and floating slurry quality;

s200, barreling and leveling the fresh concrete, sealing and standing, and testing the normal-pressure bleeding rate of the concrete;

s300, taking out the sealed and static concrete, and uniformly stirring the concrete from the bottom;

s400, testing the time expansion degree and the time air content of the stirred concrete to obtain an expansion degree time loss change value, an air content time change value and a test compressive strength index;

s500, calculating the quotient of the indexes of the same concrete mixture under the action of the detected and reference foam control agents, wherein the quotient of the indexes of the concrete mixture comprises the following steps: the quotient of the stacking height, the quotient of the change of the expansion degree with time, the quotient of the change of the gas content with time, the quotient of the float pulp quality, the quotient of the apparent bubble quantity, the quotient of the normal-pressure bleeding rate and the compressive strength ratio.

2. The method for evaluating the performance test of the concrete foam control agent according to claim 1, wherein the slump of the reference and tested concrete is 190 ± 20mm in S100.

3. The method for evaluating the performance test of the concrete foam control agent according to claim 1, wherein the initial air content of the reference and tested concrete is controlled to be 4.0 ± 0.2% by the change of the amount of the foam control agent in S100.

4. The method for evaluating a performance test of a concrete foam control agent according to claim 1, wherein the initial expansion degree is 500 ± 30mm in S100; in S400, the degree of temporal expansion is > 380 mm.

5. The method for evaluating the performance test of the concrete foam control agent according to claim 1, wherein the sealing and standing time in S200 is 2 hours.

6. The method for testing and evaluating the performance of the concrete foam control agent according to claim 1, wherein the compressive strength indexes comprise 3d, 7d and 28d compressive strength indexes.

7. The method for evaluating the performance test of the concrete foam control agent according to claim 1, wherein the method for detecting the pile height comprises the following steps: after concrete mixing is finished, unloading and uniformly mixing to make slump, after standing, observing the wrapping property of the newly mixed concrete, and measuring the stone stacking height, namely, the slump obtained by subtracting the slump of the position of the bottom of the stone stack from the slump of the concrete can be regarded as the stone stacking height.

8. The method for testing and evaluating the performance of the concrete foam control agent according to claim 1, wherein the method for detecting the apparent bubble amount comprises the following steps: and (3) testing a mould by using a cube, filling fresh concrete once, placing the mould on a vibration table to vibrate for a plurality of seconds, placing the mould for a plurality of hours to harden, then demoulding, numbering each side surface and photographing, and manually counting the number of air holes with the diameter of each side surface more than 2mm in the picture, namely the apparent bubble quantity.

9. The performance test evaluation method of the concrete foam control agent according to claim 1, wherein the detection method of the floating slurry quality comprises the following steps: and (3) once loading fresh concrete to a cubic test mould, placing the test mould on a vibration table for vibration for several seconds, scraping the laitance on the surface of the test block by using a metal ash scraper until no obvious falling layer exists after the concrete is hardened, and weighing the scraped laitance to obtain the laitance mass.

10. The method for testing and evaluating the performance of the concrete foam control agent according to claim 1, wherein the quotient of each index of the concrete under the action of the tested and reference foam control agent obtained in the step S500 is evaluated, and the evaluation indexes are as follows:

I. selecting index items which are less than 0.5 in the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying amount of the gas content, the quotient of the floating slurry quality, the quotient of the apparent bubble amount and the quotient of the normal-pressure bleeding rate, and the index items of which the compressive strength ratio is more than 1.03, wherein when more than 7 items meet the requirements, the bubble control performance is excellent;

II. Selecting index items which are less than 1 in the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying amount of the gas content, the quotient of the floating slurry quality, the quotient of the apparent bubble amount and the quotient of the normal-pressure bleeding rate, and the index items of which the compressive strength ratio is more than 1.00, wherein if more than 5 of the index items meet the requirements, the foam control performance is good;

and III, selecting index items with the compressive strength ratio of less than 1 and index items with the compressive strength ratio of less than 1 from the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying value of the gas content, the quotient of the float pulp quality, the quotient of the apparent bubble quantity and the quotient of the normal-pressure bleeding rate, wherein when more than 5 of the index items meet the requirements, the bubble control performance is poor.

Technical Field

The invention relates to the technical field of concrete foam control agents, in particular to a performance test evaluation method of a concrete foam control agent.

Background

The bubbles can be divided into bubbles, foams and sol bubbles, and the bubbles in the concrete belong to the sol bubbles. The foam control agent has the advantages that the size of bubbles formed by the foam control agent in the concrete stirring process is uniform (20-1000 mu m), the migration speed is low, the possibility of mutual coalescence is low, and the bubbles can basically exist in the concrete stably, so that the foam control agent is favorable for the concrete and can improve the properties of frost resistance, water retention and the like in the concrete, and other bubbles and foams are unfavorable for the workability of the concrete.

With the rapid development and intense commercial competition of commercial concrete in recent years, how to better control the cost of concrete becomes the development trend of the commercial concrete industry, and in addition, natural resources are less and less, materials used for producing concrete are gradually deteriorated, but the performance requirements on concrete are higher and higher, and under the condition, the construction requirements of concrete can not be met through the adjustment of the mixing ratio of concrete. At present, the construction performance of concrete is mainly improved by adjusting a foam control agent, and the foam control agent is a concrete admixture which can enable concrete or mortar and cement paste to be generated in a fine and uniform distribution manner and can retain micro bubbles after hardening. After the foam control agent is added into the concrete or mortar, the fluidity and plasticity of the concrete or mortar can be improved, and the durability can be improved. Therefore, the foam control agent plays a crucial role in improving the workability and durability of concrete.

The conventional method for testing the foam control agent judges the influence of the foam control agent on the strength of concrete by testing the initial air content of the concrete; the air-entraining effect of the air-entraining agent was also determined by the concentration of the saturated alkali solution air-entraining agent at the inflection point of the change in surface tension in the evaluation method disclosed in "evaluation method of air-entraining effect of air-entraining agent for cement concrete" having publication No. CN103926174B, publication No. 2016, 6/1/2016.

However, the above test method cannot accurately evaluate the comprehensive performance of the foam control agent, cannot distinguish the difference between different foam control agents, and is to be further improved.

Disclosure of Invention

In order to solve the problem that the difference between different foam control agents cannot be distinguished because the comprehensive performance of the foam control agent cannot be accurately evaluated by the conventional foam control agent testing method in the background art, the invention provides a performance testing and evaluating method for a concrete foam control agent, which comprises the following steps:

s100, testing concrete mixture indexes of fresh concrete under the action of a reference and a detected foam control agent, wherein the concrete mixture indexes comprise initial expansion degree, stacking height, initial gas content, apparent bubble content and floating slurry quality;

s200, barreling and leveling the fresh concrete, sealing and standing, and testing the normal-pressure bleeding rate of the concrete;

s300, taking out the sealed and static concrete, and uniformly stirring the concrete from the bottom;

s400, testing the time expansion degree and the time air content of the stirred concrete to obtain an expansion degree time loss change value, an air content time change value and a test compressive strength index;

s500, calculating the quotient of the indexes of the same concrete mixture under the action of the detected and reference foam control agents, wherein the quotient of the indexes of the concrete mixture comprises the following steps: the quotient of the stacking height, the quotient of the change of the expansion degree with time, the quotient of the change of the gas content with time, the quotient of the float pulp quality, the quotient of the apparent bubble quantity, the quotient of the normal-pressure bleeding rate and the compressive strength ratio.

On the basis of the scheme, in S100, the slump of the reference concrete and the slump of the tested concrete are 190 +/-20 mm.

On the basis of the scheme, in S100, the initial air content of the reference concrete and the initial air content of the tested concrete are controlled to be 4.0 +/-0.2% through the change of the dosage of the foam control agent.

On the basis of the scheme, in S100, the initial expansion degree is 500 +/-30 mm; in S400, the degree of temporal expansion is > 380 mm.

On the basis of the above scheme, further, in S200, the sealing standing time is 2 hours.

On the basis of the scheme, the compressive strength indexes comprise 3d compressive strength indexes, 7d compressive strength indexes and 28d compressive strength indexes.

On the basis of the above scheme, further, the method for detecting the stacking height comprises: after concrete mixing is finished, unloading and uniformly mixing to make slump, after standing, observing the wrapping property of the newly mixed concrete, and measuring the stone stacking height, namely, the slump obtained by subtracting the slump of the position of the bottom of the stone stack from the slump of the concrete can be regarded as the stone stacking height.

On the basis of the above scheme, further, the method for detecting the apparent bubble amount comprises the following steps: and (3) testing a mould by using a cube, filling fresh concrete once, placing the mould on a vibration table to vibrate for a plurality of seconds, placing the mould for a plurality of hours to harden, then demoulding, numbering each side surface and photographing, and manually counting the number of air holes with the diameter of each side surface more than 2mm in the picture, namely the apparent bubble quantity.

On the basis of the above scheme, further, the method for detecting the apparent bubble amount comprises the following steps: and (3) filling fresh concrete once by using a cube test mold of 150mm multiplied by 150mm, placing on a vibration table to vibrate for 10 seconds, placing for 24 hours to harden, then demolding, numbering 4 side faces and taking a picture, and manually counting the number of air holes with the diameter of the 4 side faces larger than 2mm in the picture, namely the apparent air bubble amount.

On the basis of the scheme, the method for detecting the floating pulp quality further comprises the following steps: and (3) once loading fresh concrete to a cubic test mould, placing the test mould on a vibration table for vibration for several seconds, scraping the laitance on the surface of the test block by using a metal ash scraper until no obvious falling layer exists after the concrete is hardened, and weighing the scraped laitance to obtain the laitance mass.

On the basis of the scheme, the method for detecting the floating pulp quality further comprises the following steps: and (3) once loading fresh concrete to the height of 20mm below the top surface of the cube test mould with the height of 150 x 150mm, placing the cube test mould on a vibration table, vibrating for 20 seconds, scraping the laitance on the surface of the test block by using a metal plaster scraper until no obvious falling layer exists after the concrete is hardened, and weighing the scraped laitance to obtain the laitance quality.

On the basis of the scheme, further, the quotient of each index of the concrete under the action of the detected and reference foam control agent obtained in the step S500 is evaluated, and the evaluation index is as follows:

I. selecting index items which are less than 0.5 in the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying amount of the gas content, the quotient of the floating slurry quality, the quotient of the apparent bubble amount and the quotient of the normal-pressure bleeding rate, and the index items of which the compressive strength ratio is more than 1.03, wherein when more than 7 items meet the requirements, the bubble control performance is excellent;

II. Selecting index items which are less than 1 in the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying amount of the gas content, the quotient of the floating slurry quality, the quotient of the apparent bubble amount and the quotient of the normal-pressure bleeding rate, and the index items of which the compressive strength ratio is more than 1.00, wherein if more than 5 of the index items meet the requirements, the foam control performance is good;

and III, selecting index items with the compressive strength ratio of less than 1 and index items with the compressive strength ratio of less than 1 from the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying value of the gas content, the quotient of the float pulp quality, the quotient of the apparent bubble quantity and the quotient of the normal-pressure bleeding rate, wherein when more than 5 of the index items meet the requirements, the bubble control performance is poor.

Compared with the prior art, the performance test evaluation method of the concrete foam control agent provided by the invention has the following technical principles and effects:

1. the reason why the quotient of the stacking height, the quotient of the change value of the expansion degree over time, the quotient of the change amount of the gas content over time, the quotient of the floating slurry quality, the quotient of the apparent bubble amount, the quotient of the normal-pressure bleeding rate and the quotient of the 3d, 7d and 28d compressive strength ratios are taken as the assessment indexes is that the main problems encountered in the concrete construction application in the market at present are the workability problems caused by the difference of the fluidity and the workability of the concrete, and the workability problems can cause the difference of the strength. The application of the foam control agent is one of the key factors causing the fluidity, the workability and the strength of the concrete. The standard and regulation directly aiming at the performance evaluation of the foam control agent are not available in China, so the method is formulated as an index for evaluating the performance difference of the foam control agent.

2. The method is simple and easy to operate, is reliable to verify, can be used for evaluating and analyzing the workability and the change of the constructability of the fresh concrete doped with the foam control agent, effectively screens out the foam control agent with high quality, reduces the loss of the construction performance and other performance of the concrete caused by the action of the foam control agent with poor quality, improves the engineering quality of the concrete, and is beneficial to improving the construction efficiency and the comprehensive benefit of the concrete.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following description will clearly and completely describe the embodiments of the present invention, and obviously, the described embodiments are a part of the embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The present invention provides the following examples:

the reference foam control agent is Y35;

the foam control agent of example 1 was AE 38;

the foam control agent of example 2 is YW-1;

foam control agent MY1 of example 3.

The concrete application performance test is carried out on the foam control agent selected in the embodiment, and the test method comprises the following steps:

the cement is P.O42.5R cement (Longyan Fufu cement); the fine aggregate is river sand (Xiamen building material) with fineness modulus of 2.7; the coarse aggregate is continuous graded broken stone (Xiamen forward building material) with the particle size of 5-20 mm; the mineral powder is S95 grade (Quanzhou Lu new building material); the fly ash is level II (Zhangzhou gangue power plant); the water for the test meets the regulation of JGJ63-2006 Water for concrete Standard; the formulation of C30 concrete is shown in Table 1, and the admixture is an additive concrete admixture conventionally used in the art:

TABLE 1C30 concrete mixing ratio

After the initial air content index and the slump of the evaluation method are reached by adjusting the dosage of the foam control agent, the performance of the concrete mixture is tested, and the test performance is shown in table 2:

the evaluation method comprises the following steps:

s100, testing concrete mixture indexes of fresh concrete under the action of a reference or detected foam control agent, wherein the concrete mixture indexes comprise initial expansion degree, stacking height, initial gas content, apparent bubble content and floating slurry quality;

s200, barreling and leveling the fresh concrete, sealing and standing for 2 hours, and testing the normal-pressure bleeding rate of the concrete;

s300, taking out the sealed and static concrete, and uniformly stirring the concrete from the bottom for three times;

s400, testing the time expansion degree and the time air content of the stirred concrete to obtain an expansion degree time loss change value and an air content time change value, and testing the compressive strength indexes of 3d, 7d and 28 d;

s500, calculating the quotient of the same concrete mixture index under the action of the detected and reference foam control agent, and evaluating the performance of the foam control agent according to the quotient of the concrete mixture index, wherein the quotient of the concrete mixture index comprises: the quotient of the stacking height, the quotient of the change of the expansion degree with time, the quotient of the change of the gas content with time, the quotient of the laitance quality, the quotient of the apparent bubble amount, the quotient of the normal-pressure bleeding rate and the ratio of the compressive strength of 3d, 7d and 28 d.

In S100, the initial slump of the reference and tested concrete is 190 +/-20 mm.

In S100, the initial air content of the benchmark concrete and the tested concrete is controlled to be 4.0 +/-0.2% through the change of the dosage of the foam control agent.

In S100, the initial expanse is 500 ± 30 mm; in S400, the degree of temporal expansion is > 380 mm.

The method for detecting the apparent bubble amount comprises the following steps: filling fresh concrete once by using a cube testing mold with the size of 150mm multiplied by 150mm, placing the cube testing mold on a vibration table to vibrate for 10 seconds, placing the cube testing mold for 24 hours to harden, then demolding, numbering and photographing 4 side surfaces, and manually counting the number of air holes with the size of more than 2mm on the 4 side surfaces in the photograph, namely the apparent air bubble amount;

the method for detecting the floating pulp quality comprises the following steps: the newly mixed concrete is arranged to the height of 20mm below the top surface of the cube test mould of 150 x 150 at one time, the cube test mould is placed on a vibration table to vibrate for 20 seconds, after the concrete is hardened, the surface laitance of the test block is scraped by a metal plaster scraper until no obvious peeling layer exists, and then the scraped laitance is weighed to obtain the laitance quality;

the detection method of the stacking height comprises the following steps: after the concrete is mixed, unloading and uniformly stirring to make slump, standing for 2min, observing the wrapping property of the newly mixed concrete, and measuring the stone stacking height, namely, the slump obtained by subtracting the slump of the position at the bottom of the stone stack from the slump of the concrete can be regarded as the stone stacking height;

in S500, foam control agent performance is evaluated by the following evaluation indexes:

I. selecting index items which are less than 0.5 in the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying amount of the gas content, the quotient of the floating slurry quality, the quotient of the apparent bubble amount and the quotient of the normal-pressure bleeding rate, wherein the index items of which the compressive strength ratio of 3d, 7d and 28d is more than 1.03 are met, and when more than 7 items meet the requirements, indicating that the bubble control performance is excellent;

II. Selecting index items which are less than 1 in the quotient of the stacking height, the quotient of the time-varying value of the expansion degree, the quotient of the time-varying amount of the gas content, the quotient of the floating slurry quality, the quotient of the apparent bubble amount and the quotient of the normal-pressure bleeding rate, and index items of which the ratio of the compressive strength of 3d to 7d to 28d is more than 1.00, wherein when more than 5 items meet the requirements, the foam control performance is good;

and III, selecting index items with the compressive strength ratio of less than 1 and index items with the compressive strength ratio of 3d, 7d and 28d of less than 1 from the quotient of the stacking height, the quotient of the change value of the expansion degree with time, the quotient of the change value of the gas content with time, the quotient of the float pulp quality, the quotient of the apparent bubble quantity and the quotient of the normal-pressure bleeding rate, and when more than 5 index items meet the requirements, indicating that the bubble control performance is poor.

Table 2 concrete performance testing of concrete foam control agents

Wherein, the detection method of the expansion degree is 'Standard test method for Performance of common concrete mixture' GB/T50020-2016; the detection method of the gas content is 'test method standard for the performance of common concrete mixture' GB/T50020-2016; the detection method of the bleeding rate is 'test method standard of common concrete mixture performance' GB/T50020-2016; the detection method of the 3d, 7d and 28d compressive strength is 'test method standard for common concrete mixture performance' GB/T50020-2016;

as can be seen from table 2:

in example 1, the quotient of the bulk height, the quotient of the change in gas content with time, the quotient of the laitance quality, the quotient of the normal-pressure bleeding rate, and the compressive strength ratio of 3d, 7d, and 28d all satisfy the requirement of I in the evaluation index, and thus it is judged that the foam control performance of the foam control agent is excellent.

In example 2, 5 items in total of the quotient of the change in the degree of expansion with time, the quotient of the change in the amount of gas with time, the quotient of the apparent bubble amount, the normal-pressure bleeding rate, and the 3d compressive strength ratio satisfy the requirements of the evaluation index III, and thus it is judged that the foam control performance of the foam control agent is poor.

In example 3, the quotient of the change in the degree of expansion with time, the quotient of the change in the amount of gas content with time, the quotient of the stack height, the quotient of the apparent bubble amount, and the 28d compressive strength ratio, all 5 items, satisfy the requirement of II in the evaluation index, and therefore, it was judged that the foam control performance of the foam control agent is good.

It is obvious to those skilled in the art that the technical solutions of the present invention can still be obtained the same as or similar to the above embodiments when the technical solutions of the present invention are changed within the following ranges, and still belong to the protection scope of the present invention.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.