CN114993881A - Detection and evaluation method for sensitivity improvement effect of concrete regulator on water reducing agent - Google Patents
Detection and evaluation method for sensitivity improvement effect of concrete regulator on water reducing agent Download PDFInfo
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Abstract
The invention provides a detection and evaluation method for the sensitivity improvement effect of a concrete regulator on a water reducing agent, the detection and evaluation method obtains reference slurry without the regulator through experiments and the critical addition amount of the water reducing agent in the comparison slurry with the regulator, then the super-doping rate R of the water reducing agent corresponding to the regulator is calculated according to the critical addition value of the water reducing agent before and after the regulator is added, the super-doping rate R can accurately evaluate the sensitivity improvement effect of the regulator on the water reducing agent, the higher the super-doping rate is, the better the sensitivity reduction effect of the regulator on the water reducing agent is, and the super-doping rate R is reduced along with the increase of the water reducing rate of the water reducing agent; meanwhile, the critical addition amount of the water reducing agent is directly used as a judgment basis through whether the slurry is isolated or not, and the isolation can be visually observed and judged through whether the slurry is secreted or a slurry ring or not, so that the detection steps are simplified, the evaluation accuracy is improved, the method is suitable for detection in clean slurry and conventional concrete, the detection result can be rapidly obtained on site, and the popularization and the application are convenient.
Description
Technical Field
The invention relates to the technical field of concrete, and particularly provides a detection and evaluation method for the sensitivity improvement effect of a concrete regulator on a water reducing agent.
Background
In order to improve the workability and performance of concrete, in addition to the gel-forming material and coarse and fine aggregate, a small amount of concrete additives which have a great influence on the performance of concrete, such as water reducing agent, early strength agent, air entraining agent, segregation reducing agent, etc., are added to improve the performance of concrete. The water reducing agent is the most used concrete additive, wherein the polycarboxylate water reducing agent is the high-performance water reducing agent which is the most widely used and has the best performance at present. However, the water retention property is changed violently due to the trace increase of the mixing amount of the water reducing agent, the wide application and development of the polycarboxylic acid high-performance water reducing agent are greatly restricted, and the difficulty in popularization and application is how to reduce the sensitivity of the polycarboxylic acid water reducing agent.
At present, the dosage range of the water reducing agent during concrete mixing is widened by using the regulator, the workability and the segregation resistance of the concrete can be improved, and the regulator has important significance for improving the construction performance of the concrete and the strength of the concrete. The method has important significance for detecting and evaluating the sensitivity of the regulator for improving the water reducing agent and guiding the addition of the regulator and the water reducing agent in the actual preparation of concrete, but the detection and evaluation method in the aspect is rarely reported in the prior art.
The patent CN105223105A discloses a method for detecting the rheological sensitivity of a polycarboxylate water reducer, which comprises the steps of reflecting the sensitive mixing amount range of the polycarboxylate water reducer by measuring the fluidity of cement paste, then carrying out high-speed stirring and low-speed stirring on three groups of cement paste added with the sensitive mixing amount range, respectively detecting the fluidity of the three groups of cement paste, calculating the fluidity difference corresponding to the high-speed stirring and the low-speed stirring under the same mixing amount, calculating the change percentage of the fluidity difference, and finally judging the sensitivity and the adaptability of the polycarboxylate water reducer according to the group number of which the change percentage is less than 10 percent: if the variation rate of the difference values of at least six items is less than 10%, judging that the sensitivity of the water reducer is weak, and indicating that the adaptability of the water reducer is good; if the difference value of at least four items is more than 10%, the water reducer is judged to have strong sensitivity, which indicates that the water reducer has poor adaptability. The detection method can only compare the sensitivity of different water reducing agents with rough sensitivity, but cannot carry out specific quantitative comparison on the sensitivity, and lacks practical guiding value for the actual preparation of concrete; the detection of the fluidity needs a specific detection device and a test environment, the detection time is long, the detection cost is high, and the method is not suitable for quick field detection; on the other hand, the performance of the modifier cannot be accurately reflected only by the sensitivity of the water reducing agent, and the performance of the modifier cannot be further evaluated.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a method for detecting and evaluating the sensitivity improvement effect of a concrete regulator on a water reducing agent, wherein the critical doping amount of the water reducing agent is judged by detecting the segregation condition of slurry, and the water reducing rate of the water reducing agent is preliminarily judged; and then detecting the critical doping amount of the water reducing agent in the slurry after the regulator is added, obtaining the super-doping rate of the water reducing agent after the regulator is added through the critical sensitive doping amount of the water reducing agent before and after the regulator is added, accurately reflecting the regulating performance of the regulator on the water reducing agent through the super-doping rate, and being applicable to the detection of cement paste or conventional concrete, conveniently and quickly obtaining a detection result, applying and guiding the actual configuration of the concrete, and also being convenient for standardized popularization and application.
In order to achieve the aim, the invention provides a detection and evaluation method for the sensitivity improvement effect of a concrete regulator on a water reducing agent, which comprises the following steps:
s1, testing sensitivity of the water reducing agent in the standard slurry:
s1-1, preparing reference slurry, pouring a water reducing agent which is 2% of the solid content X of the cement into a stirrer for stirring;
s1-2, continuously dripping the water reducing agent into the standard slurry obtained in the step S1-1, uniformly stirring, and recording the weight A of the dripped water reducing agent 1 ；
S1-3, quickly injecting the mixed reference slurry into a conical section mould, pouring the mixed reference slurry on a flat plate, and observing whether segregation occurs in the reference slurry within 10S: if the reference slurry on the flat plate is not isolated, the steps S1-1, S1-2 and S1-3 are continuously repeated, and the dropping weight A of the water reducing agent is recorded every time n And A is n >A n-1 Wherein n is a positive integer; if the standard slurry on the flat plate is isolated, the dropping weight of the water reducing agent is A n When the reference slurry is just separated, the critical weight M is sensitively doped into the water reducing agent in the reference slurry 1 ＝X*2％+A n-1 ；
S2, testing sensitivity of the water reducing agent in the slurry:
s2-1, preparing comparison serous fluid and comparing the serous fluidThe adding weight of the medium water reducing agent is M 1 The weight of the regulator is 0.6 percent of the solid content X of the cement, the rest proportion of the comparison slurry is the same as the standard slurry in the step S1, wherein the weight of the regulator is added into the total weight of water in the comparison slurry, and the mixture is poured into a stirrer for stirring;
s2-2, continuously dripping the water reducing agent into the comparison slurry obtained in the step S2-1, uniformly stirring, and recording the weight of the dripped water reducing agent as B 1 ；
S2-3, quickly injecting the mixed comparison slurry into a conical section mould and pouring the mixed comparison slurry on a flat plate, and observing whether the comparison slurry is separated in 10S or not: if the comparison slurry on the plate is not separated, the steps S2-1, S2-2 and S2-3 are continuously repeated, and the dropping weight B of the water reducing agent is recorded every time n And B is n >B n-1 Wherein n is a positive integer; if the comparison slurry on the flat plate is isolated, the dropping weight of the water reducing agent is B n The water reducer is just separated compared with the slurry, and the critical weight M is doped sensitively compared with the water reducer in the slurry 2 ＝M 1 +B n-1 ；
S3, calculating the super-doping rate R (M) of the water reducing agent in the comparative slurry after the regulator is added 2 -M 1 )/M 1 The effect of the regulator on improving the sensitivity of the water reducer can be accurately evaluated by the super-doping rate R, the higher the super-doping rate is, the better the effect of the regulator on reducing the sensitivity of the water reducer is, and the super-doping rate R is reduced along with the increase of the water reduction rate of the water reducer;
the standard slurry in the step S1-1 is cement paste or conventional concrete proportioning;
when the standard neat paste is the neat cement paste, the super-doping rate of the neat cement paste is as follows: under the condition that no glue material is added, the ratio of the difference of the using amounts of the water reducing agents when the standard clean cement paste and the comparative clean cement paste respectively reach the segregation critical state to the using amount of the water reducing agent when the standard clean cement paste reaches the segregation critical state; the judgment standard of the separation in the step S1-3 and the step S2-3 is that water secretion rings appear around the cement paste on the flat plate;
when the standard slurry is conventional concrete, the concrete parallel ratio super-doping rate is as follows: under the condition that the dosage of the glue material is not changed, the ratio of the difference of the dosage of the water reducing agent used when the reference concrete and the comparative concrete slurry respectively reach the segregation critical state to the dosage of the water reducing agent used when the reference concrete slurry reaches the segregation critical state; and judging the isolation in the step S1-3 and the step S2-3 to be that a cement slurry ring, namely a bleeding ring, appears around the concrete on the flat plate.
Preferably, the water reducing agent in the reference slurry is sensitively doped with the critical weight M 1 Can evaluate the water reducing rate and the critical weight M of the water reducing agent 1 The larger the value is, the lower the water reducing rate of the water reducing agent is, and the critical weight M 1 The smaller the value, the higher the water reducing rate of the water reducing agent; passing through critical weight M 1 The water reducing rate performance index of the used water reducing agent can be preliminarily judged.
Preferably, the proportion of the cement paste refers to GB/T8077-: 300g of cement, 87g of water and 6g of water reducing agent.
Preferably, the difference between the dripping weights of the two adjacent water reducing agents in the step S1-3 is delta A i ＝A i -A i-1 ，ΔA i <ΔA i-1 Wherein i is a positive integer greater than 1.
Preferably, the Δ A is i ≤X*0.2％。
Preferably, the water reducing agent is a polycarboxylic acid water reducing agent.
Preferably, the stirring in the step S1-1 and the step S2-1 is set to be slow stirring for 60S and then fast stirring for 60S.
Preferably, the steps S1 and S2 are repeated twice, and the critical weight M 1 And M 2 The average of the two operations was taken.
Preferably, the step S1 is repeated twice to obtain two critical weights M 1 The difference between them should be less than M 1 6% of the average; two critical weights M obtained by repeating the step S2 twice 2 The difference between them should be less than M 2 6% of the average value.
Preferably, the super-doping rate of the neat paste is in positive correlation with the super-doping rate of the conventional concrete.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the detection and evaluation method for the sensitivity improvement effect of the concrete regulator on the water reducing agent, the reference slurry without the regulator is obtained through experiments, the critical addition amount of the water reducing agent in the slurry is compared with the critical addition amount of the water reducing agent in the slurry after the regulator is added, then the super-doping rate R of the water reducing agent corresponding to the regulator is obtained through calculation according to the upper limit value of the water reducing agent before and after the regulator is added, the effect of the regulator on the sensitivity improvement of the water reducing agent can be accurately evaluated through the super-doping rate R, the higher the super-doping rate is, the better the sensitivity effect of the regulator on the water reducing agent is, and the super-doping rate R is reduced along with the increase of the water reducing rate of the water reducing agent;
(2) in the detection and evaluation method, the critical addition amount of the water reducing agent is used as a judgment basis according to whether the slurry is isolated, and the isolation can be directly observed and judged according to whether the slurry is secreted or a slurry ring, so that the evaluation accuracy is obviously improved; compared with the detection period of hours or even days in the prior art, the detection and evaluation method has the advantages that the time consumption is remarkably reduced, and the detection efficiency is improved; moreover, the judgment of the slurry segregation can be simultaneously suitable for the detection of the clean slurry and the conventional concrete, the judgment standards of the two are unified, the super-doping rates R of the same regulator in the clean slurry and the conventional concrete are in positive correlation, namely, the detection result can be quickly obtained on site only through a slurry cleaning experiment, the effect of the regulator in the concrete can be fed back, and the popularization and the application are convenient;
(3) according to the detection and evaluation method, the performance of the regulator is quickly evaluated and judged through cement paste detection, the basic performance index of the regulator is accurately mastered in time, and the method can be used for quickly screening a proper regulator in a laboratory; the performance of the regulator used in the conventional concrete is detected by the same detection and evaluation method, so that the performance quantification index of the regulator actually applied in the concrete is accurately obtained, the regulator can be used for screening a proper regulator, the upper limit of the addition amount of the polycarboxylic acid water reducing agent corresponding to the regulator can be determined, the addition amount of the water reducing agent in the actual preparation process of the concrete can be guided, and the important guidance value is provided in the actual concrete proportioning;
(4) the critical weight M of the removed reference slurry is detected by the steps of the invention 1 The water reducing rate performance index of the used water reducing agent can be preliminarily judged, namely, the accurate evaluation on the performance of the regulator and the evaluation on the water reducing rate index of the water reducing agent can be respectively realized through one detection, the application range can be expanded, and the concrete preparation practice can be guided more conveniently;
(5) the detection and evaluation method disclosed by the invention is rapid in detection, a large test field is not required, 1-2 experimenters are enough, the bleeding/slurry phenomenon generated in the separation process can be visually and accurately judged by naked eyes, specific detection equipment is not required, the detection cost is lower, and the real-time detection of a production field is very convenient.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a diagram showing a state of segregation of a cement paste in example 1 of the present invention, in which FIG. 1A is a diagram showing a state of non-segregation of a reference paste; FIG. 1B is a diagram showing the segregation state of a reference net slurry showing a water discharge ring; FIG. 1C is a graph comparing neat paste unseparated states; FIG. 1D is a diagram showing the segregation state of the discharge rings of the comparison net slurry; the water circle is clearly visible around the net pulp in fig. 1B and 1D;
FIG. 2 is a diagram showing the judgment of the segregation state of the conventional concrete in example 2 of the present invention, wherein FIG. 2A is a diagram showing the non-segregation state of the reference conventional concrete; FIG. 2B is a diagram showing the segregation state of a weepage circle of the reference conventional concrete; FIG. 2C is a diagram comparing the non-segregation state of conventional concrete; FIG. 2D is a diagram comparing the segregation state of the conventional concrete showing the bleeding circle; the grout rings are clearly visible around the conventional concrete of fig. 2B and 2D.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. These examples are intended to illustrate the invention and are not intended to limit the scope of the invention.
Example 1
The detection and evaluation of the sensitivity improvement effect of the concrete regulator on the water reducing agent in the cement paste specifically comprises the following steps:
s1, testing sensitivity of the water reducer in the standard cement paste:
s1-1, preparing standard cement paste, wherein the proportion of the cement paste refers to GB/T8077-: 300g of cement, 87g of water and 6g of polycarboxylic acid water reducing agent, mixing and pouring into a stirrer for stirring, wherein the slow stirring is firstly carried out for 60s, and then the fast stirring is carried out for 60 s;
s1-2, continuously dropwise adding a polycarboxylic acid water reducing agent into the standard cement paste obtained in the step S1-1, wherein the first dropwise adding amount of the water reducing agent is equal to 0.2% of the solid content, uniformly stirring, and recording the weight of the dropwise added water reducing agent as A 1 ；
S1-3, quickly injecting the mixed reference cement paste into a conical section mould and pouring the mixed reference cement paste on flat glass, and observing whether segregation occurs in the reference paste within 10S: if no water secretion rings appear around the reference slurry on the plate glass, as shown in figure 1A, the reference cement paste is not separated, the steps S1-1, S1-2 and S1-3 are continuously repeated, and the dropping weight A of the water reducing agent is recorded once per dropping n And A is n >A n-1 Wherein n is a positive integer; the weight difference value of the two adjacent water reducing agents is delta A i ＝A i -A i-1 ，ΔA i <ΔA i-1 Where i is a positive integer greater than 1, Δ A i ≤X*0.2％。
If a water secretion ring appears around the reference clean cement paste on the plate glass, as shown in FIG. 1B, namely the reference clean cement paste is already separated, the water reducing agent is continuously added with the weight A n When the reference slurry is just separated, the critical weight M is sensitively doped into the water reducing agent in the reference cement paste 1 ＝300*2％+A n-1 ；
S2, testing sensitivity of the water reducing agent in the cement paste by comparison:
s2-1, preparing comparison cement paste, wherein the proportion of the comparison cement paste is as follows GB/T8077-: 300g of cement, 85.2g of water and M weight of polycarboxylate superplasticizer 1 g, adding 1.8g of regulator (the water content of the regulator is more than 90%), mixing and pouring into a stirrer for stirring, and slowly stirring for 60s and then quickly stirring for 60 s;
s2-2, continuously dropwise adding a polycarboxylate water reducer into the comparative cement paste obtained in the step S2-1, wherein the dropwise adding amount of the water reducer is less than or equal to 0.2% of the solid content each time, uniformly stirring, and recording the weight of the dropwise added water reducer as B 1 ；
S2-3, quickly injecting the mixed comparative cement paste into a conical section mould and pouring the mixed comparative cement paste on flat glass, and observing whether segregation occurs in 10S of the comparative cement paste: if no water secretion rings appear around the comparison cement paste on the plate glass, as shown in figure 1C, the comparison paste is not separated, the steps S2-1, S2-2 and S2-3 are continuously repeated, and the dropping weight B of the water reducing agent is recorded once per dropping n And B is n >B n-1 Wherein n is a positive integer; if a water secretion ring appears around the comparison cement paste on the plate glass, as shown in figure 1D, namely the comparison cement paste is already separated, the water reducing agent is continuously added with the weight of B n The time is just separated compared with the cement paste, and the critical weight M is sensitively doped compared with the water reducing agent in the cement paste 2 ＝M 1 +B n-1 ；
S3, calculating the super-doping rate of the water reducing agent in the comparative cement paste after the regulator is added, repeating the operation steps S1 and S2 twice to obtain an average value, and the specific calculation result is shown in Table 1.
TABLE 1 Cement paste super-doping test recording table
As can be seen from the results in Table 1, the difference between the results of the two parallel tests is very small, which shows that the test result of the detection and evaluation method is accurate and has high repeatability; meanwhile, the one-time complete test time is about 30min, the standard can be established for the test of the reference slurry, the test time can be saved by about half without repeating every time, and the test of the super-doping rate in the clean slurry can be independently completed by one person.
Example 2
The method specifically comprises the following steps of:
s1, testing sensitivity of the water reducer in the standard conventional concrete:
s1-1, preparing standard conventional concrete according to a conventional mixing ratio of C30 in the laboratory, wherein the mixing ratio is shown in Table 2, the weight of the added polycarboxylate superplasticizer is 2% of the total weight of the cement, and the mixture is poured into a stirrer for stirring; the reference concrete can be converted into 15-30L of total concrete volume according to the proportion to be weighed and trial-matched, and the trial-matched amount is reduced;
s1-2, continuously dropwise adding a polycarboxylic acid water reducing agent into the standard conventional concrete in the step S1-1, wherein the dropwise adding amount of the water reducing agent is less than or equal to 0.2% of the solid content of the cement each time, uniformly stirring, and recording the weight A of the dropwise added water reducing agent 1 ；
S1-3, quickly injecting the mixed standard conventional concrete into a small container and pouring the mixed standard conventional concrete on a flat glass, and observing whether segregation occurs in the standard conventional concrete within 10S: if no bleeding circle appears around the reference slurry on the plate glass, the reference concrete slurry is not isolated, as shown in FIG. 2A, the steps S1-1, S1-2 and S1-3 are continuously repeated, and the dropping weight A of the water reducing agent is recorded once per dropping n And A is n >A n-1 Wherein n is a positive integer; the weight difference value of the two adjacent water reducing agents is delta A i ＝A i -A i-1 ，ΔA i <ΔA i-1 Where i is a positive integer greater than 1, Δ A i Less than or equal to 0.2 percent of X. If a bleeding circle is observed around the standard conventional concrete on the plate glass, namely the standard conventional concrete is isolated, as shown in figure 2B, the weight of the water reducing agent added is A n The standard conventional concrete is just separated, and the critical weight M is sensitively doped into the water reducing agent in the standard conventional concrete 1 ＝X*2％+A n-1 ；
S2, comparing the sensitivity test of the water reducing agent in the conventional concrete:
s2-1, preparing conventional concrete, wherein the adding weight of the regulator is 0.6% of the total weight of the cement, and the rest proportion is the same as that of the standard conventional concrete, wherein the adding amount of the regulator is calculated by the total weight of water in the concrete, mixing and pouring the mixture into a mixer for stirring, and slowly stirring for 60S and then quickly stirring for 60S;
s2-2, continuously adding the water reducing agent dropwise into the conventional concrete compared with the conventional concrete in the step S2-1, wherein the first dropwise adding amount of the water reducing agent is 0.2% of the solid content of the cement, uniformly stirring, and recording the weight of the dropwise added water reducing agent as B 1 ；
S2-3, quickly injecting the mixed concrete into a small container and pouring the mixed concrete on a flat glass, and observing whether segregation occurs in 10S compared with the conventional concrete: if no bleeding circle appears around the conventional concrete on the plate glass, as shown in FIG. 2C, the conventional concrete is not isolated, the steps S2-1, S2-2 and S2-3 are continuously repeated, and the dropping weight B of the water reducing agent is recorded once per dropping n And B is n >B n-1 Wherein n is a positive integer; if a bleeding circle is observed around the conventional concrete on the flat plate, as shown in FIG. 2D, i.e. the concrete is isolated compared with the conventional concrete, the weight of the water reducer added is B n The concrete is just separated compared with the conventional concrete, and the water reducing agent is sensitively doped with critical weight M compared with the water reducing agent in the conventional concrete 2 ＝M 1 +B n-1 ；
S3, calculating the super-doping rate of the water reducer in the conventional concrete compared with the water reducer added with the regulator, repeating the steps twice to obtain an average value, wherein the specific proportion and the calculation result are shown in Table 2.
TABLE 2 conventional concrete parallel ratio super-doping test record table
Experimental example 1
Cement paste and conventional concrete parallel super-doping experiment
Three concrete regulators commonly found in the market are purchased and named as A-Guangxi BaoTing, B-Hunan Yiyou and C-Changshan Sundao respectively, the water reducing agents are eastern rain rainbow polycarboxylic acid water reducing agents with the water reducing rate of 20%, the super-doping rates of the three regulators in cement paste and conventional concrete are detected according to the detection methods of example 1 and example 2, and the detection results are shown in Table 3.
TABLE 3 results of parallel super-mixing experiments of different conditioners in cement paste and conventional concrete
The results in table 3 show that the detection and evaluation method provided by the invention can accurately evaluate the sensitivity performance of different regulators for reducing the water reducing agent, and the super-doping rates of different regulators in cement paste and conventional concrete are obviously and positively correlated, so that the detection method can accurately feedback the use performance of the regulator in conventional concrete only through a simple cement paste super-doping experiment, and is convenient for quickly and preliminarily judging the performance of the regulator; the super-doping critical level of the water reducing agent can be further determined through a super-doping experiment of the conventional concrete, and the super-doping critical level can be used for guiding the proportion selection of the water reducing agent in the conventional concrete.
Experimental example 2
Water reducing agent performance detection for improving different water reducing rates by using regulator
The conditioning performance of the conditioning agent C-changshan sons in example 1 was examined for three polycarboxylic acid water reducing agents of different water reducing rates, named X-jinyu, Y-camizu ruida and Z-east rainrainbow, respectively, using the conditioning agent C-changshan sons in example 1 as a baseline conditioning agent and the detection methods of examples 1 and 2, respectively, with the water reducing rates being in the order: 15%, 18%, and 25%, and the specific detection results are shown in Table 4.
TABLE 4 Water reducing agent Performance Table for improving different Water reducing rates by adjusting agent
From the results in Table 4, it can be seen that the higher the water reducing rate of the water reducing agent is, the higher the critical mixing amount M of the water reducing agent in cement paste and conventional concrete 1 The lower the critical doping amount of the water reducing agent in the detection method, the higher the water reducing rate of the water reducing agent can be judged; meanwhile, the super-doping rate R of the water reducing agent with different water reducing rates regulated by the regulator in cement paste and conventional concrete is also obviously and positively correlated.
Experimental example 3
Concrete workability and strength comparison verification are carried out according to the conventional concrete proportioning in example 2, the super-doping rate R of the water reducing agent in the conventional concrete in example 2 is 18%, 4 groups are respectively set for experimental control, wherein the adding weight of the regulator is 0.6% of the total weight of the cement, the super-doping rates of the polycarboxylate water reducing agent are respectively set to be 0%, 50% R, 90% R and 110% R, and the weight of the corresponding polycarboxylate water reducing agent is respectively: wherein, the workability is evaluated by slump, and the specific experimental results are shown in Table 5.
TABLE 5 conventional concrete Properties (weight/kg) at different super-doping rates
The results in Table 5 show that when the mixing amount of the water reducing agent is less than the corresponding super-mixing rate R of the regulator, the prepared concrete has no phenomena of segregation and stone leakage, the slump is maintained at about 200mm, and the prepared concrete has good workability; once the super-doping rate of the water reducing agent exceeds the corresponding super-doping rate R of the regulator, the prepared concrete has obvious segregation and stone leakage, the slump is obviously increased, and the workability of the concrete is poor; meanwhile, the strength of the C30 concrete prepared in the super-doping rate range can reach the standard, once the super-doping rate is exceeded, the strength of the concrete is obviously reduced, and the strength standard is lower than the strength required by C30, so that the grade of the concrete is reduced.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A detection and evaluation method for the sensitivity improvement effect of a concrete regulator on a water reducing agent is characterized by comprising the following steps:
s1, testing sensitivity of the water reducer in the reference slurry:
s1-1, preparing reference slurry, pouring a water reducing agent which is 2% of the solid content X of the cement into a stirrer for stirring;
s1-2, continuously dripping the water reducing agent into the standard slurry obtained in the step S1-1, uniformly stirring, and recording the weight A of the dripped water reducing agent 1 ；
S1-3, quickly injecting the mixed reference slurry into a conical section mould, pouring the mixed reference slurry on a flat plate, and observing whether segregation occurs in the reference slurry within 10S: if the reference slurry on the flat plate is not isolated, the steps S1-1, S1-2 and S1-3 are continuously repeated, and the dropping weight A of the water reducing agent is recorded every time n And A is n >A n-1 Wherein n is a positive integer; if the standard slurry on the flat plate is isolated, the dropping weight of the water reducing agent is A n When the reference slurry is just separated, the critical weight M is sensitively doped into the water reducing agent in the reference slurry 1 ＝X*2％+A n-1 ；
S2, testing sensitivity of the water reducing agent in the slurry:
s2-1, preparing comparison slurry, wherein the weight of the comparison slurry added with water reducing agent is M 1 Adding a regulator with the weight of 0.6% of the solid content X of the cement, adding the rest of the comparative slurry into the reference slurry obtained in the step S1, wherein the weight of the regulator is added into the total weight of water in the comparative slurry, and pouring the mixture into a stirrer for stirring;
s2-2, continuously dropwise adding the water reducing agent into the comparison slurry obtained in the step S2-1, uniformly stirring, and recording the weight B of the dropwise added water reducing agent 1 ；
S2-3, mixing the prepared comparative slurryQuickly pouring into a conical section mould and pouring on a flat plate, and observing whether segregation occurs in the slurry 10 s: if the comparison slurry on the plate is not separated, the steps S2-1, S2-2 and S2-3 are continuously repeated, and the dropping weight B of the water reducing agent is recorded every time n And B is n >B n-1 Wherein n is a positive integer; if the comparison slurry on the flat plate is isolated, the dropping weight of the water reducing agent is B n The water reducer is just separated compared with the slurry, and the critical weight M is doped sensitively compared with the water reducer in the slurry 2 ＝M 1 +B n-1 ；
S3, calculating the super-doping rate R (M) of the water reducing agent in the comparative slurry after the regulator is added 2 -M 1 )/M 1 The effect of the regulator on improving the sensitivity of the water reducer can be accurately evaluated by the super-doping rate R, the higher the super-doping rate is, the better the effect of the regulator on reducing the sensitivity of the water reducer is, and the super-doping rate R is reduced along with the increase of the water reduction rate of the water reducer;
the standard slurry in the step S1-1 is cement paste or conventional concrete proportioning;
when the standard clean slurry is the clean cement slurry, the judgment standard of the segregation in the step S1-3 and the step S2-3 is that water secretion rings appear around the clean cement slurry on the flat plate;
and when the standard clear grout is conventional concrete, judging the isolation in the step S1-3 and the step S2-3 that a cement grout ring appears around the concrete on the flat plate.
2. The method for detecting and evaluating the improvement effect of the concrete conditioner on the sensitivity of the water reducer according to claim 1, wherein the reference slurry contains a critical weight M for sensitive incorporation of the water reducer 1 Can evaluate the water reducing rate and the critical weight M of the water reducing agent 1 The larger the value, the lower the water reducing rate of the water reducing agent, and the critical weight M 1 The smaller the value, the higher the water reducing rate of the water reducing agent.
3. The method for detecting and evaluating the effect of the concrete conditioner on the improvement of the sensitivity of the water reducer as claimed in claim 1, wherein the proportion of the cement paste refers to GB/T8077-: 300g of cement, 87g of water and 6g of water reducing agent.
4. The method for detecting and evaluating the effect of improving the sensitivity of the concrete conditioner to the water reducer according to claim 1, wherein the difference between the dripping weights of the two adjacent water reducers in the step S1-3 is Delta A i ＝A i -A i-1 ，ΔA i <ΔA i-1 Wherein i is a positive integer greater than 1.
5. The method for detecting and evaluating the effect of improving the sensitivity of a concrete conditioner to a water reducing agent according to claim 4, wherein Δ A is i ≤X*0.2％。
6. The method for detecting and evaluating the effect of improving the sensitivity of a concrete conditioner to a water reducing agent according to claim 1, wherein the water reducing agent is a polycarboxylic acid water reducing agent.
7. The method for detecting and evaluating the effect of improving the sensitivity of a concrete conditioner to a water reducing agent according to claim 1, wherein the stirring settings in the steps S1-1 and S2-1 are first slow stirring for 60S and then fast stirring for 60S.
8. The method for detecting and evaluating the effect of improving the sensitivity of a concrete conditioner to a water reducing agent according to claim 1, wherein the steps S1 and S2 are repeated twice, and the critical weight M is 1 And M 2 The average of the two runs was taken.
9. The method for detecting and evaluating the effect of improving the sensitivity of a concrete conditioner to a water reducing agent according to claim 8, wherein the two critical weights M obtained by repeating the step S1 twice 1 The difference between them should be less than M 1 6% of the average; two critical weights M obtained by repeating the operation of step S2 twice 2 The difference between them should be less than M 2 6% of the average value.
10. The method for detecting and evaluating the sensitivity improvement effect of the concrete conditioner on the water reducing agent according to claim 1, wherein the super-doping rate of the cement paste is in positive correlation with the super-doping rate of the conventional concrete.
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| CN105223105A (en) * | 2015-11-06 | 2016-01-06 | 湖北工业大学 | A kind of poly carboxylic acid series water reducer stream sensitize detection method |
| CN112390560A (en) * | 2019-08-14 | 2021-02-23 | 陕西科之杰新材料有限公司 | Low-sensitivity concrete workability regulator and preparation method thereof |
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