CN113552121A - Method for evaluating mixing uniformity of cement stabilized macadam mixture - Google Patents
Method for evaluating mixing uniformity of cement stabilized macadam mixture Download PDFInfo
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- 239000004568 cement Substances 0.000 title claims abstract description 79
- 238000002156 mixing Methods 0.000 title claims abstract description 53
- 239000000203 mixture Substances 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 24
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims abstract description 47
- 238000011156 evaluation Methods 0.000 claims abstract description 25
- 238000004448 titration Methods 0.000 claims abstract description 20
- 239000002245 particle Substances 0.000 claims description 32
- 239000011148 porous material Substances 0.000 claims description 28
- 238000012216 screening Methods 0.000 claims description 13
- 230000008569 process Effects 0.000 claims description 9
- 238000005070 sampling Methods 0.000 claims description 5
- 238000007873 sieving Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000004898 kneading Methods 0.000 claims 1
- 238000007711 solidification Methods 0.000 abstract description 10
- 230000008023 solidification Effects 0.000 abstract description 10
- 238000000465 moulding Methods 0.000 abstract description 7
- 239000000463 material Substances 0.000 abstract description 5
- 238000012958 reprocessing Methods 0.000 abstract description 5
- 238000004364 calculation method Methods 0.000 abstract description 4
- 238000011077 uniformity evaluation Methods 0.000 abstract description 4
- 239000004575 stone Substances 0.000 abstract 1
- 238000003756 stirring Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 4
- 238000003805 vibration mixing Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000010426 asphalt Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004422 calculation algorithm Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 238000002591 computed tomography Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 239000010977 jade Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000011158 quantitative evaluation Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
- G01N21/79—Photometric titration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
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Abstract
本发明涉及一种水泥稳定碎石混合料拌和均匀性的评价方法，包括：对水泥稳定碎石混合料进行拌和，在拌和过程中在不同的时间点至少选取三个位点进行取样，得到样品；对所述样品进行EDTA滴定，测定EDTA的消耗量及每个时间点EDTA消耗量对应水泥剂量的极差值X；对所述样品进行筛分，得到样品的各筛孔通过率极差值的和RX和各筛孔通过率与标准值的差值的和T；将水泥剂量的极差值X、RX和T和预设值进行对比是否均匀。选用新的评价指标和计算方式，从水泥均匀性和级配均匀性两个方面实现了对刚拌和水泥稳定碎料均匀性的评价，而非待凝固成型后才对均匀性进行评价，有效地避免了凝固成型后均匀性指标不合格带来的重新处理的劣势。The invention relates to a method for evaluating the mixing uniformity of cement-stabilized crushed stone mixture. EDTA titration is carried out to the sample, the range value X of the corresponding cement dosage of the consumption of EDTA and the EDTA consumption at each time point is measured; X, X and T of the difference between the passing rate of each sieve hole and the standard value; compare the range X, R X and T of the cement dosage with the preset value to see if it is uniform. Using new evaluation indicators and calculation methods, the evaluation of the uniformity of the just-mixed cement stable crushed material is realized from the two aspects of cement uniformity and gradation uniformity, rather than the uniformity evaluation after solidification and molding, effectively. The disadvantage of reprocessing caused by unqualified uniformity index after solidification and forming is avoided.
Description
Technical Field
The invention relates to the field of cement mixing, in particular to an evaluation method for mixing uniformity of a cement stabilized macadam mixture.
Background
At present, the newly implemented "road pavement base course construction technical rules" (JTG/TF 20-2015) imposes strict requirements on the mixing uniformity in terms of the mixing process and mixing time. Namely, the uniformity of the freshly mixed cement stabilized macadam mixture plays a crucial role in ensuring the quality of subsequent pavements, and the mixing has a direct influence on the uniformity of the mixture. The traditional mixing mode widely used at present is double-shaft horizontal rail type forced mixing, and the mixing mode has the advantages of simple operation process, convenient site construction and capability of completing mixing of large amount of mixture in short time. However, the traditional mixing method is easy to cause the cement particles to generate the phenomenon of agglomeration, so that the hydration reaction is insufficient, the utilization rate of the cement is low, and the mixing speed gradient exists. And the problem that the mixture is unevenly mixed to cause the surface of the coarse aggregate to be exposed to white is frequently caused.
The study on the mixing uniformity of the newly-mixed cement stabilized macadam is characterized in that an image of a section of a test piece is obtained based on an image processing technology or a CT scanning technology, and the difference is the difference of the actual processing and evaluation modes of the section image.
For example, the research on the novel method for evaluating the uniformity of the asphalt mixture (Pengyong, Sunli military, Dongyi beautiful jade, academic university of Tongji (Nature science edition), 2005, 33(2):166 + 168) adopts the magnitude of the aggregate accumulated area value in the equal area on the cross section, and Wu Wen Liang and the like (Wu Wen Lizhi, Zhang Tong, the evaluation on the uniformity of the asphalt mixture by the digital image processing technology [ J ]. academic university of Jilin (Gong), 2009, 39(4):921 + 925.) consider the distribution position, the distribution quantity, the area ratio and the rotational inertia of the aggregate. Although the method is simple, subjective experience judgment is more, errors are larger, and some practical situations can be reflected to a certain extent.
The research has certain reference significance for uniformity evaluation of cement stabilized macadam, but the uniformity evaluation indexes are evaluation performed after the mixture is formed, quantitative evaluation of a cementing material and grading variability in a new mixing state of the mixture is lacked, and material mixing uniformity is a necessary condition for ensuring subsequent paving and compacting of the material.
Disclosure of Invention
In view of the problems in the prior art, the invention aims to provide an evaluation method for mixing uniformity of a cement stabilized macadam mixture, which realizes evaluation of the uniformity of the cement stabilized macadam mixture just mixed from two aspects of cement uniformity and grading uniformity through redesign of evaluation indexes in the evaluation method, but not evaluates the mixing uniformity after solidification molding, and effectively avoids the disadvantage of reprocessing caused by unqualified uniformity indexes after solidification molding.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides an evaluation method for mixing uniformity of a cement stabilized macadam mixture, which comprises the following steps:
mixing the cement stabilized macadam mixture, and selecting at least three points at different time points in the mixing process to sample to obtain a sample;
performing EDTA titration on the sample, and determining the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dosage at each time point;
screening the sample to obtain the sum R of the extreme difference values of the sieve pore passing rates of the sampleXAnd the sum T of the difference values of the passing rate of each sieve pore and the standard value;
the extreme difference value X of the cement dosage and the sum R of the extreme difference values of the passing rates of all the sieve holesXAnd comparing the sum T of the difference value of each sieve pore passing rate and the standard value with a preset value, and if the sum T is matched with the preset value, the result is uniform.
According to the invention, through redesigning the evaluation method of cement mixing uniformity, selecting new evaluation indexes and calculation modes, the uniformity evaluation of the stable crushed aggregates of the just-mixed cement is realized from the two aspects of cement uniformity and grading uniformity, instead of evaluating the uniformity after solidification and molding, and the disadvantage of reprocessing caused by disqualified uniformity indexes after solidification and molding is effectively avoided.
In the present invention, the sampling at least three points at different time points during the mixing process means that at least 3 points are sampled at each time point, that is, three samples are obtained by sampling once, and the time points can be selected from 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, 160s, 170s, 180s, 190s, 200s, 210s, 220s, 230s, 240s, 250s, 260s, 270s, 280s, 290s, 300s, 400s, 500s and the like. If the position can be the central shaft position A of the stirring blade of the machine, the middle position B of the stirring blade and the top end position C of the outer side of the stirring blade;
in the invention, EDTA standard curves are drawn according to the cement dosage of 0%, 2%, 4%, 6% and 8% respectively (namely EDTA titration and fitting are carried out on a uniformly mixed mixture containing specific cement content), so that EDTA consumption y in different cement dosages x and three particle size ranges is obtained by adopting the following EDTA standard curves;
y =2.7525x +2.2 in the particle size range 0-9.5mm
Particle size range 9.5-19mm, y =1.605x +0.84 excluding 9.5mm end point values
Particle size range 19-31.5mm, y =1.230x +0.520 excluding 19mm end point values
In a preferred embodiment of the present invention, the mixing method includes vibration mixing and non-vibration mixing.
In a preferred embodiment of the present invention, the mixing time is not less than 10s, and may be, for example, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, 160s, 170s, 180s, 190s, 200s, 210s, 220s, 230s, 240s, 250s, 260s, 270s, 280s, 290s, or 300s, but is not limited to the above-mentioned values, and other values not listed in the above range are also applicable.
According to the preferable technical scheme, the EDTA titration is carried out on the sample, the sample is screened in three particle size ranges, then EDTA titration is carried out on the screened particle fraction products, and the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dose at each time point are counted.
As a preferred technical scheme of the invention, the three particle size ranges comprise less than or equal to 9.5mm and 9.5-19mm, and do not comprise 9.5mm and 19-31.5mm, but do not comprise 19 mm.
As a preferred technical scheme of the invention, the screening form comprises water washing screening.
In a preferred embodiment of the present invention, the rotation speed of the vibratory mixing is 55 to 75r/min, for example, 55r/min, 56r/min, 57r/min, 58r/min, 59r/min, 60r/min, 61r/min, 62r/min, 63r/min, 64r/min, 65r/min, 66r/min, 67r/min, 68r/min, 69r/min, 70r/min, 71r/min, 72r/min, 73r/min, 74r/min or 75r/min, but is not limited to the above-mentioned values, and other values not mentioned in this range are also applicable.
As a preferable technical scheme of the invention, the sum R of the extreme difference values of the passing rates of the sieve holesXIs composed of
RX=(Xmax31.5-Xmin31.5)+(Xmax26.5-Xmin26.5)+(Xmax19-Xmin19)+(Xmax9.5-Xmin9.5)+(Xmax4.75-Xmin4.75)+(Xmax2.36-Xmin2.36)+(Xmax0.6-Xmin0.6)+(Xmax0.075-Xmin0.075) In the formula, Xmax0.075Is the maximum value of the passing rate of the sieve of 0.075mm in the sample, Xmin0.075Is the minimum value of the pass rate through a 0.075mm mesh in the sample.
As a preferable embodiment of the present invention, the sum of the difference values between the respective screen mesh passage rates and the standard value and the screen mesh passage rate in T is a passage rate at which the screen mesh passes through a screen mesh of 31.5mm, 26.5mm, 19mm, 9.5mm, 4.75mm, 2.36mm, 0.6mm and 0.075mm, respectively.
T in the present invention can refer to the following algorithm:
T=(A1-D1)+(A2-D2)+(A3-D3)+(A4-D4)+(A5-D5)+(A6-D6)+(A7-D7)+(A8-D8)
the standard value D in Table 1 below is the mass percentage passing through each sieve opening corresponding to the composition grading. Such as D1, D2, D3, D4, D5, D6, D7 and D8 which are respectively 100.0, 96.6, 76.7, 48.7, 31.0, 20.5, 10.3 and 4.3.
TABLE 1
As a preferred embodiment of the present invention, the evaluation method includes:
mixing the cement stabilized macadam mixture, and selecting at least three points at different time points in the mixing process to sample to obtain a sample; performing EDTA titration on the sample, wherein the EDTA titration on the sample is to screen the sample in three particle size ranges, then performing EDTA titration on the screened particle fraction product, and counting the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dose at each time point; the three particle size ranges comprise less than or equal to 9.5mm and 9.5-19mm, and do not comprise 9.5mm and 19-31.5mm, but do not comprise 19 mm;
screening the sample to obtain the sum R of the extreme difference values of the sieve pore passing rates of the sampleXAnd the sum T of the difference values of the passing rate of each sieve pore and the standard value; the sum R of the extreme difference values of the passing rates of the sieve poresXIs = (X)max31.5-Xmin31.5)+(Xmax26.5-Xmin26.5)+(Xmax19-Xmin19)+(Xmax9.5-Xmin9.5)+(Xmax4.75-Xmin4.75)+(Xmax2.36-Xmin2.36)+(Xmax0.6-Xmin0.6)+(Xmax0.075-Xmin0.075) In the formula, Xmax0.075Is the maximum value of the passing rate of the sieve of 0.075mm in the sample, Xmin0.075Is the minimum value of the passing rate of the sieve pore of 0.075mm in the sample;
the screen mesh passing rates in T and the difference value of each screen mesh passing rate and the standard value are respectively the passing rates of the screen meshes of 31.5mm, 26.5mm, 19mm, 9.5mm, 4.75mm, 2.36mm, 0.6mm and 0.075 mm;
the extreme difference value X of the cement dosage and the sum R of the extreme difference values of the passing rates of all the sieve holesXAnd comparing the sum T of the difference value of each sieve pore passing rate and the standard value with a preset value, and if the sum T is matched with the preset value, the result is uniform.
In the invention, for the part with the size fraction less than or equal to 9.5mm, if the range of the dosage of the cement is less than or equal to 0.10%, the cement is considered to be uniformly distributed in the size fraction range, for the part with the size fraction of 9.5mm-19mm, the part with the size fraction of 9.5mm is not included, and if the range of the dosage of the cement is less than or equal to 0.20%, the cement is considered to be uniformly distributed in the size fraction range; and if the range of the extreme difference value X of the cement dosage is less than or equal to 0.25 percent for the part with the size fraction of 19mm-31.5mm and not including the part with the size of 19mm, the cement is considered to be uniformly distributed in the size fraction range.
Grading uniformity: sum of very different values of the passing rates of the sieve holes RXLess than 15 percent, and the sum T of the difference values of the passing rate of each sieve pore and the standard value is less than 30 percent, the particles in the size fraction range are uniformly distributed.
It should be noted that the criterion for determining whether the uniformity of cement and the gradation uniformity are acceptable is not limited to the numerical criterion provided by the present invention, but the logical framework of the determination is provided according to the present invention, that is, the skilled person can change the cement dosage deviation value X, the sum R of the deviation values of the passing rates of the sieve holes according to the expected valueXAnd the sum T of the difference values of the passing rates of the sieve holes and the standard value, but the sum R of the extreme difference values of the passing rates of the sieve holes cannot be obtainedXAnd the passing rate of each sieve pore is equal toThe sum T of the differences of the standard values reaches the criterion of standard at the same time.
Compared with the prior art, the invention at least has the following beneficial effects:
according to the invention, through redesigning the evaluation method of the cement mixing uniformity, selecting new evaluation indexes, sampling points and calculation modes, evaluating the uniformity of the stable crushed aggregates which are just mixed with cement from the aspects of the cement uniformity and the grading uniformity, rather than evaluating the uniformity after solidification and molding, and through comprehensively judging the uniformity of the mixed materials, the disadvantage of reprocessing caused by unqualified uniformity indexes after solidification and molding is effectively avoided.
Detailed Description
To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:
example 1
The embodiment provides an evaluation method for mixing uniformity of a cement stabilized macadam mixture, which comprises the following steps:
mixing the cement stabilized macadam mixture (adopting vibration mixing, the rotating speed is 55r/min, the vibration intensity is 3), and respectively selecting three sites (a central shaft position A of a mixing blade of a mixer, a middle position B of the mixing blade and a top end position C of the outer side of the mixing blade) at different time points (10 s, 30s, 50s, 80s, 120s, 160s, 200s and 300 s) in the mixing process to sample to obtain a sample;
performing EDTA titration on the sample, namely screening the sample in three particle size ranges, performing EDTA titration on the screened particle fraction product, and counting the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dose at each time point; the three particle size ranges comprise less than or equal to 9.5mm and 9.5-19mm, and do not comprise 9.5mm and 19-31.5mm, but do not comprise 19 mm;
drawing an EDTA standard curve (namely performing EDTA titration and fitting by adopting a uniformly mixed mixture containing specific cement content) according to the cement dosage of 0%, 2%, 4%, 6% and 8%, so as to obtain different cement dosages x and EDTA consumption y in three particle size ranges by adopting the following EDTA standard curve;
y =2.7525x +2.2 in the particle size range 0-9.5mm
Particle size range 9.5-19mm, y =1.605x +0.84 excluding 9.5mm end point values
Particle size range 19-31.5mm, y =1.230x +0.520 excluding 19mm end point values
And calculating the cement dosage and the difference value thereof in the sample by adopting the fitting curve.
The samples were water washed and sieved and the sieving results are detailed in table 6. Obtaining the sum R of the extreme difference values of the screen mesh passing rates of the samplesXAnd the sum T of the difference values of the passing rate of each sieve pore and the standard value; the sum R of the extreme difference values of the passing rates of the sieve poresXIs = (X)max31.5-Xmin31.5)+(Xmax26.5-Xmin26.5)+(Xmax19-Xmin19)+(Xmax9.5-Xmin9.5)+(Xmax4.75-Xmin4.75)+(Xmax2.36-Xmin2.36)+(Xmax0.6-Xmin0.6)+(Xmax0.075-Xmin0.075) In the formula, Xmax0.075Is the maximum value of the passing rate of the sieve of 0.075mm in the sample, Xmin0.075Is the minimum value of the passing rate of the sieve pore of 0.075mm in the sample; the difference value between each sieve aperture passing rate and the standard value and the sieve aperture passing rate in T are the passing rates of sieve apertures of 31.5mm, 26.5mm, 19mm, 9.5mm, 4.75mm, 2.36mm, 0.6mm and 0.075mm respectively;
the extreme difference value X of the cement dosage and the sum R of the extreme difference values of the passing rates of all the sieve holesXAnd comparing the sum T of the difference value of each sieve pore passing rate and the standard value with a preset value, and details are shown in tables 5 and 7.
Example 2
The embodiment provides an evaluation method for mixing uniformity of a cement stabilized macadam mixture, which comprises the following steps:
mixing the cement stabilized macadam mixture (adopting non-vibration mixing at the rotating speed of 55 r/min), and sampling at three points (a central shaft position A of a mixing blade of a mixer, a middle position B of the mixing blade and a top end position C of the outer side of the mixing blade) at different time points (10 s, 30s and 50 s) in the mixing process to obtain a sample;
performing EDTA titration on the sample, namely screening the sample in three particle size ranges, performing EDTA titration on the screened particle fraction product, and counting the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dose at each time point; the three particle size ranges comprise less than or equal to 9.5mm and 9.5-19mm, and do not comprise 9.5mm and 19-31.5mm, but do not comprise 19 mm;
drawing an EDTA standard curve (namely performing EDTA titration and fitting by adopting a uniformly mixed mixture containing specific cement content) according to the cement dosage of 0%, 2%, 4%, 6% and 8%, so as to obtain different cement dosages x and EDTA consumption y in three particle size ranges by adopting the following EDTA standard curve;
y =2.7525x +2.2 in the particle size range 0-9.5mm
Particle size range 9.5-19mm, y =1.605x +0.84 excluding 9.5mm end point values
Particle size range 19-31.5mm, y =1.230x +0.520 excluding 19mm end point values
And calculating the cement dosage and the difference value thereof in the sample by adopting the fitting curve.
Washing and screening the sample, and obtaining the sum R of the extreme difference values of the passing rates of all the sieve pores of the sample according to the screening results detailed in Table 6XAnd the sum T of the difference values of the passing rate of each sieve pore and the standard value; the sum R of the extreme difference values of the passing rates of the sieve poresXIs = (X)max31.5-Xmin31.5)+(Xmax26.5-Xmin26.5)+(Xmax19-Xmin19)+(Xmax9.5-Xmin9.5)+(Xmax4.75-Xmin4.75)+(Xmax2.36-Xmin2.36)+(Xmax0.6-Xmin0.6)+(Xmax0.075-Xmin0.075) In the formula, Xmax0.075Is the maximum value of the passing rate of the sieve of 0.075mm in the sample, Xmin0.075Is the minimum value of the passing rate of the sieve pore of 0.075mm in the sample; the difference value between each sieve aperture passing rate and the standard value and the sieve aperture passing rate in T are the passing rates of sieve apertures of 31.5mm, 26.5mm, 19mm, 9.5mm, 4.75mm, 2.36mm, 0.6mm and 0.075mm respectively;
the extreme difference value X of the cement dosage and the sum R of the extreme difference values of the passing rates of all the sieve holesXAnd comparing the sum T of the difference value of each sieve pore passing rate and the standard value with a preset value, and details are shown in tables 5 and 7.
The aggregate for cement stabilized macadam in the above examples was tested according to the relevant method in the road engineering aggregate test protocol. Screening tests of single grain size of coarse and fine aggregates, crushing value, needle-like particle content, dust content and the like were carried out, as shown in tables 2 and 3, PC325 cement for cement stabilized macadam (delayed coagulation) was selected, and examined according to the relevant method in Highway engineering cement and cement concrete test protocols (JTGE30-2005) as shown in Table 4.
TABLE 2
TABLE 3
TABLE 4
TABLE 5
TABLE 6
TABLE 7
From the above results, it can be seen that: for the part with the size fraction less than or equal to 9.5mm, if the extreme difference value X of the cement dosage is less than or equal to 0.10 percent, the cement is considered to be uniformly distributed in the size fraction range; combining the results of examples 1 and 2, it can be seen that the standard of example 1 is reached after 50s of stirring, while example 2 is not reached;
for the size fraction of 9.5mm-19mm, excluding the 9.5mm part, if the extreme difference value X of the cement dosage is less than or equal to 0.20%, the cement distribution in the size fraction range is considered to be uniform; combining the results of examples 1 and 2, it can be seen that the standard of example 1 is reached after 50s of stirring, while example 2 is not reached;
for the part with the size fraction of 19mm-31.5mm and not including the part with the size fraction of 19mm, if the extreme difference value X of the cement dosage is less than or equal to 0.25 percent, the cement is considered to be uniformly distributed in the size fraction range; the results of examples 1 and 2 show that the standard of example 1 was reached after 50 seconds of stirring, while example 2 did not reach the standard.
Sum of very different values of the passing rates of the sieve holes RXLess than 15 percent, and the sum T of the difference values of the passing rate of each sieve pore and the standard value is less than 30 percent, then the particles are uniformly distributed in the size fraction range; from the analysis of the results of examples 1 and 2, it was found that only 50 seconds of stirring in example 1 reached a satisfactory value.
According to the embodiment, the evaluation method for the cement mixing uniformity is redesigned, and the new evaluation index and calculation mode are selected, so that the uniformity of the stable crushed aggregates which are just mixed with cement is evaluated from the two aspects of the cement uniformity and the grading uniformity, but the uniformity is not evaluated after solidification and forming, and the disadvantage of reprocessing caused by unqualified uniformity index after solidification and forming is effectively avoided.
The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (10)
1. The evaluation method for the mixing uniformity of the cement stabilized macadam mixture is characterized by comprising the following steps of:
mixing the cement stabilized macadam mixture, and sampling at least three points at different time points in the mixing process to obtain a sample;
performing EDTA titration on the sample, and determining the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dosage at each time point;
screening the sample to obtain the sum R of the extreme difference values of the sieve pore passing rates of the sampleXAnd the sum T of the difference values of the passing rate of each sieve pore and the standard value;
the extreme difference value X of the cement dosage and the sum R of the extreme difference values of the passing rates of all the sieve holesXAnd comparing the sum T of the difference value of each sieve pore passing rate and the standard value with a preset value, and if the sum T is matched with the preset value, the result is uniform.
2. The method of claim 1, wherein the mixing is performed in a manner selected from the group consisting of vibratory mixing and non-vibratory mixing.
3. The method according to claim 1 or 2, wherein the mixing time is 10s or more.
4. The evaluation method according to claim 3, wherein the EDTA titration is performed on the sample by screening the sample in three particle size ranges, and then EDTA titration is performed on the screened fraction product, and the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dose at each time point are counted.
5. The evaluation method according to claim 4, wherein the three particle size ranges include ≦ 9.5mm, 9.5-19mm, excluding 9.5mm and 19-31.5mm, excluding 19 mm.
6. The method of claim 4 or 5, wherein the form of sieving comprises water wash sieving.
7. The method of claim 2, wherein the rotation speed of the vibro-kneading is 55 to 75 r/min.
8. The method according to claim 1 or 7, wherein the sum R of the difference values of the respective screen mesh passage rates isXIs composed of
Rx=(Xmax31.5-Xmin31.5)+(Xmax26.5-Xmin26.5)+(Xmax19-Xmin19)+(Xmax9.5-Xmin9.5)+(Xmax4.75-Xmin4.75)+(Xmax2.36-Xmin2.36)+(Xmax0.6-Xmin0.6)+(Xmax0.075-Xmin0.075) In the formula, Xmax0.075Passing through a 0.075mm mesh in the sampleMaximum value, Xmin0.075Is the minimum value of the pass rate through a 0.075mm mesh in the sample.
9. The method according to claim 8, wherein the sum of the difference values of the respective screen passage rates from the standard values and the screen passage rate in T is a passage rate through a screen of 31.5mm, 26.5mm, 19mm, 9.5mm, 4.75mm, 2.36mm, 0.6mm and 0.075mm, respectively.
10. The evaluation method according to claim 1 or 9, characterized in that the evaluation method comprises:
mixing the cement stabilized macadam mixture, and selecting at least three points at different time points in the mixing process to sample to obtain a sample; performing EDTA titration on the sample; performing EDTA titration on the sample, namely screening the sample in three particle size ranges, then performing EDTA titration on the screened particle-size products respectively, and counting the consumption of EDTA and the extreme difference value X of the consumption of EDTA corresponding to the cement dose at each time point; the three particle size ranges comprise less than or equal to 9.5mm and 9.5-19mm, and do not comprise 9.5mm and 19-31.5mm, but do not comprise 19 mm;
screening the sample to obtain the sum R of the extreme difference values of the sieve pore passing rates of the sampleXAnd the sum T of the difference values of the passing rate of each sieve pore and the standard value; the sum R of the extreme difference values of the passing rates of the sieve poresXIs = (X)max31.5-Xmin31.5)+(Xmax26.5-Xmin26.5)+(Xmax19-Xmin19)+(Xmax9.5-Xmin9.5)+(Xmax4.75-Xmin4.75)+(Xmax2.36-Xmin2.36)+(Xmax0.6-Xmin0.6)+(Xmax0.075-Xmin0.075) In the formula, Xmax0.075Is the maximum value of the passing rate of the sieve of 0.075mm in the sample, Xmin0.075Is the minimum value of the passing rate of the sieve pore of 0.075mm in the sample; the difference value between each sieve aperture passing rate and the standard value and the sieve aperture passing rate in T are the passing rates of sieve apertures of 31.5mm, 26.5mm, 19mm, 9.5mm, 4.75mm, 2.36mm, 0.6mm and 0.075mm respectively;
the extreme difference value X of the cement dosage and the sum R of the extreme difference values of the passing rates of all the sieve holesXAnd comparing the sum T of the difference value of each sieve pore passing rate and the standard value with a preset value, and if the sum T is matched with the preset value, the result is uniform.
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