CN113218805A - Evaluation detection and classification method for building waste regenerated coarse aggregate - Google Patents
Evaluation detection and classification method for building waste regenerated coarse aggregate Download PDFInfo
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Abstract
The invention provides an evaluation and detection method of construction waste regenerated coarse aggregate, which comprises the following steps: s1, obtaining i parts of test construction waste recycled coarse aggregate; the i is more than or equal to 5, and the proportion of the bricks of each test construction waste regenerated coarse aggregate is different; s2, detecting the P value and w value of each test construction waste regenerated coarse aggregatexValue, and QaA value; s3, according to formula P ═ a × wx b×Qa cFitting the P value, w in S2xValue, QaObtaining parameters a, b and c; s4, detecting the water absorption w of the construction waste regenerated coarse aggregate to be evaluatedxAnd crush value QaThen, based on the parameters a, b, c obtained in S3 and the formula P ═ a × wx b×Qa cAnd obtaining the total content P of the bricks and the mortar of the construction waste recycled coarse aggregate to be evaluated. The evaluation and detection method provided by the invention overcomes the limitation of visual manual sorting method, and can conveniently and reliably obtain different resultsAnd (4) regenerating the brick and mortar content in the coarse aggregate in batches.
Description
Technical Field
The invention relates to a quantitative detection method, in particular to an evaluation detection and classification method for construction waste regenerated coarse aggregates.
Background
The building garbage recycled coarse aggregate is particles which are processed by waste concrete, bricks, mortar and the like and have the particle size of more than 4.75 mm. Due to the complex sources of construction wastes, the problem of large differences of the components of waste concrete, bricks and mortar also exists in different batches of recycled aggregates of the same specification produced by the same manufacturer, and the discreteness of the quality of the recycled coarse aggregates has great influence on the performance.
The component difference of bricks and mortar in the construction waste recycled coarse aggregate mainly has obvious influence on the water absorption rate and crushing value index of the construction waste recycled coarse aggregate. The mortar and the bricks are in loose porous structures, and the water absorption and crushing values of the mortar and the bricks are greater than those of the crushed concrete blocks and the natural aggregates, wherein the water absorption and crushing values of the bricks are the largest, and the mortar is the second and the concrete blocks are the smallest. Therefore, the mixing proportion of the construction waste recycled coarse aggregate used for inorganic binder stabilizing materials or cement concrete is greatly different from that of natural coarse aggregate. Tests show that the optimal water content of the inorganic binder stabilizing material is increased along with the increase of the contents of bricks and mortar; the recycled aggregate cement concrete has a large amount of water entering the pores of the recycled aggregate, so that the water consumption is always higher than the unit water consumption calculated by the current specification in order to ensure the workability during mixing. For inorganic binder stabilization materials, good shrinkage performance is important to control base shrinkage cracking. And the water loss rate of the components with high water absorption such as bricks and the like after water loss is increased more than the increase of the dry shrinkage strain, so that the dry shrinkage coefficient is reduced. In addition, other durability indexes such as the scouring resistance and the fatigue performance are reduced along with the increase of the content of the bricks, so that the bricks and the mortar are weak points in the regenerated coarse aggregate of the construction waste, the content of the bricks and the mortar when the regenerated coarse aggregate is used is strictly controlled, and accordingly, the regenerated coarse aggregate is classified and applied to a proper scene, and the method is an important factor for ensuring the engineering quality and controlling the economic cost of the use of the regenerated coarse aggregate. Therefore, how to quickly and reliably determine the total content of bricks and mortar in the recycled coarse aggregate of the construction waste is a problem to be solved when the recycled coarse aggregate is used.
In view of the above, there is a need to provide an evaluation and detection method for construction waste recycled coarse aggregate, which solves or at least alleviates the above technical drawbacks.
Disclosure of Invention
The invention mainly aims to provide a classification method of construction waste regenerated coarse aggregates, and aims to solve the technical problem in the prior art of rapidly and reliably judging the total content of bricks and mortar in a batch of construction waste regenerated coarse aggregates.
In order to achieve the purpose, the invention provides an evaluation and detection method of construction waste regenerated coarse aggregate, which comprises the following steps:
s1, obtaining i parts of test construction waste recycled coarse aggregate; the i is more than or equal to 5, the test construction waste regenerated coarse aggregate comprises bricks, mortar and concrete blocks, and the proportion of the bricks of each test construction waste regenerated coarse aggregate is different;
s2, detecting the P value and w value of each test construction waste regenerated coarse aggregatexValue, and QaA value; wherein P is the total content of bricks and mortar, and wxFor water absorption, said QaIs the crush value;
s3, according to formula P ═ a × wx b×Qa cFitting the P value, w in S2xValue, QaObtaining parameters a, b and c;
s4, detecting the water absorption w of the construction waste regenerated coarse aggregate to be evaluatedxAnd crush value QaThen, based on the parameters a, b, c obtained in S3 and the formula P ═ a × wx b×Qa cAnd obtaining the total content P of the bricks and the mortar of the construction waste recycled coarse aggregate to be evaluated.
Further, in the step S3, the equation P is a × wx b×Qa cFitting the median P value, w, of said S2xValue, QaDegree of fit R of value2≥0.85。
Further, in the step S1, when the coarse aggregate regenerated from the test construction waste is obtained, the particle sizes of the bricks, the mortar and the concrete block are all larger than 4.75 mm.
Further, in the step S1, the raw material of each of the sample construction waste recycled coarse aggregates in the i parts of test construction waste recycled coarse aggregates is derived from the same batch;
and in the i parts of the coarse aggregate regenerated by the test construction waste, the proportion of the bricks of different parts of the coarse aggregate regenerated by the test construction waste is increased in an equal difference mode.
Further, the method for detecting the water absorption rate comprises the following steps:
s21, preprocessing; wherein the pretreatment comprises soaking a sample in water and weighing at the early stage;
the sample immersion includes: selecting a sample from the construction waste regenerated coarse aggregate to be detected, dividing the sample, and soaking the sample in water to obtain a soaking sample;
the earlier stage weighing comprises: weighing the total mass m of the dried water-absorbing material and the container1；
S22, taking the soaking sample, removing free water on the soaking sample, wiping the surface water of the soaking sample by the water-absorbing material which is soaked and wrung to obtain a saturated face-dry sample and a used water-absorbing material, and weighing the mass m of the saturated face-dry sample3；
S23, drying the saturated dried noodle sample to obtain a dried sample, and weighing the mass m of the dried sample0(ii) a Putting the used water absorbent into the containing container for drying, and weighing the used water absorbent and the containing container after dryingTotal mass m of2；
S24 according to the formula
Calculating the water absorption wx。
Further, in the step S21, the water level of the sample when immersed is higher than the top surface height of the sample; the soaking time of the sample in water is not less than 24 h.
Further, the step S21 and the step S23 are consistent in the drying temperature, and the drying temperature is 105 ℃ ± 5 ℃.
Further, the crush value QaThe detection method comprises the following steps: sampling from the construction waste regeneration coarse aggregate to be tested, and sieving to obtain a sample with the grain size of 9.5-13.2 mm; the crushing value Q is carried out after the samples with the grain diameter specification of 9.5 mm-13.2 mm are reduced to the preset qualityaThe detection test of (3).
Further, the method also comprises the following steps:
s5, continuously carrying out the total content P of the bricks and the mortar and the water absorption w on the subsequent construction waste regenerated coarse aggregatexAnd the crush value QaAnd supplementing the data of the detection test of the subsequent construction waste recycled coarse aggregate into the fitting of the step S3.
The invention also provides a classification method of the construction waste regenerated coarse aggregate, which comprises the steps of obtaining the total content P of bricks and mortar of the construction waste regenerated coarse aggregate to be evaluated according to any one of the evaluation detection methods, and classifying the construction waste regenerated coarse aggregate to be evaluated according to the total content P of the bricks and the mortar of the construction waste regenerated coarse aggregate to be evaluated.
Compared with the prior art, the invention has the following advantages:
according to the invention, through sieving a first sample, easily-sorted bricks are manually selected, i parts of building garbage recycled coarse aggregates with different brick proportions are prepared with mortar, concrete blocks and the like which are not easily sorted for standby, and the prepared building garbage with different proportions is detectedP value and w of the regenerated coarse aggregatexValue, and QaValue, then using the formula P ═ a × wx b×Qa cAnd fitting the detection data to obtain parameters a, b and c. Carrying out water absorption detection on each subsequent batch of samples to obtain the overall water absorption wxAnd obtaining the integral crushing value Q according to a standard test method T0316aI.e. according to the formula P ═ a × wx b×Qa cAnd calculating parameters a, b and c to obtain the total content P of the bricks and the mortar.
The evaluation and detection method provided by the invention overcomes the limitation of visual manual sorting method, and can conveniently and reliably obtain the contents of bricks and mortar in different batches of regenerated coarse aggregates only by sorting and preparing the spare materials with different brick proportions from the first batch of materials, detecting the brick and mortar contents, the water absorption rate and the crushing value indexes, and substituting each batch of materials into a corresponding fitting formula according to the measured overall water absorption rate and crushing value. In addition, the invention can rapidly and reliably detect the content of bricks and mortar in each batch of recycled coarse aggregates with larger source type difference of construction wastes, has better actual engineering operability under the actual condition of different levels of field quality control, and provides basis for judging the application scene and the use strategy of the batch, adjusting the application grade in time, ensuring the engineering quality of the recycled coarse aggregates, controlling the economic cost and the like.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
It should be noted that all the directional indicators (such as the upper and lower … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture, and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.
Moreover, the technical solutions in the embodiments of the present invention may be combined with each other, but it is necessary to be able to be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent, and is not within the protection scope of the present invention.
It should be known that, in order to be able to obtain the total content of bricks and mortar in the construction waste regenerated coarse aggregate quickly and reliably, apply the construction waste regenerated coarse aggregate to a suitable scene in a classified manner, ensure the engineering quality of the use of the regenerated coarse aggregate and control the economic cost, the invention provides an evaluation detection method of the construction waste regenerated coarse aggregate, which comprises the following steps:
s1, obtaining i parts of test construction waste recycled coarse aggregate; the i is more than or equal to 5, the test construction waste regenerated coarse aggregate comprises bricks, mortar and concrete blocks, and the proportion of the bricks of each test construction waste regenerated coarse aggregate is different;
s2, detecting the P value and w value of each test construction waste regenerated coarse aggregatexValue, and QaA value; wherein P is the total content of bricks and mortar, and wxFor water absorption, said QaIs the crush value;
s3, according to formula P ═ a × wx b×Qa cFitting the P value, w in S2xValue, QaObtaining parameters a, b and c;
s4, detecting the water absorption w of the construction waste regenerated coarse aggregate to be evaluatedxAnd crush value QaThen, based on the parameters a, b, c obtained in S3 and the formula P ═ a × wx b×Qa cAnd obtaining the total content P of the bricks and the mortar of the construction waste recycled coarse aggregate to be evaluated.
Wherein it is to be understood that the water absorption rate w of the construction waste reclaimed coarse aggregate to be evaluated is detectedxAnd crush value QaW of the construction waste recycled coarse aggregate to be evaluated can be obtainedxValue and QaThe values are compared with the parameters a, b, c obtained in S3 and the formula P ═ a × wx b×Qa cAnd jointly calculating to obtain the P value of the construction waste regenerated coarse aggregate to be evaluated.
The skilled person will know that i parts represent integer parts, which in the present invention is mainly used to describe the parts of the test construction waste recycled coarse aggregate, and the proportions of each test construction waste recycled coarse aggregate are different, especially the proportion of bricks is needed to be distinguished for the subsequent calculation and fitting.
In addition, after i parts of the test construction waste regenerated coarse aggregate are prepared, the total content, the water absorption rate and the crushing value of bricks and mortar in each part of the test construction waste regenerated coarse aggregate need to be respectively detected for subsequent fitting; when each test building waste regenerated coarse aggregate is detected, the average value of multiple detections is taken as detection data according to the corresponding standard requirement, so that the detection error is reduced.
And after the total content, the water absorption rate and the crushing value of the bricks and the mortar of each test construction waste regenerated coarse aggregate are detected, fitting the detection data of the i test construction waste regenerated coarse aggregates by using the fitting formula so as to obtain parameters in the fitting formula.
It should be noted that, after the parameters in the fitting formula are fitted, the total content of bricks and mortar in each batch of the construction waste recycled coarse aggregate can be directly calculated by only knowing the data of the overall water absorption rate and the crushing value of each batch of the construction waste recycled coarse aggregate (i.e. the construction waste recycled coarse aggregate to be evaluated).
The general idea of the above embodiments can be understood as follows: screening a first sample, manually selecting easily-sorted bricks, preparing i parts of construction waste regenerated coarse aggregates with different brick proportions together with mortar, concrete blocks and the like which are not easily sorted for later use, and detecting the P values and w values of the prepared construction waste regenerated coarse aggregates with different proportionsxValue, and QaValue, then using the formula P ═ a × wx b×Qa cAnd fitting the detection data to obtain parameters a, b and c.
Carrying out water absorption detection on each subsequent batch of samples to obtain the overall water absorption wxAnd obtaining the integral crushing value Q according to a standard test method T0316a。
Then, the content P% of bricks and mortar in each batch of samples is calculated according to the following formula, and can be accurate to 0.1%:
P＝a×wx b×Qa c
in connection with the analysis of the specific case, the symbols in the formula can be understood as:
a, b, c-fitting parameters obtained by experiments;
wx-water absorption (%) of the construction waste recycled coarse aggregate;
Qaconstruction waste recycled coarse aggregate crush value (%)
P is the total content (%) of bricks and mortar in the construction waste recycled coarse aggregate.
The evaluation and detection method provided by the embodiment overcomes the limitation of a visual manual sorting method, and can conveniently and reliably obtain the contents of bricks and mortar in different batches of regenerated coarse aggregates only by sorting and preparing the spare materials with different brick proportions from the first batch, detecting the brick and mortar contents, the water absorption rate and the crushing value indexes, and substituting each batch into a corresponding fitting formula according to the measured overall water absorption rate and crushing value.
The evaluation and detection method can conveniently and reliably detect the content of bricks and mortar in each batch of regenerated coarse aggregates with large differences in the types of construction waste sources, has good actual engineering operability under the actual condition of different levels of on-site quality control, and provides a basis for judging the application scenes and the use strategies of the batches, adjusting the application grades in time, ensuring the engineering quality of the regenerated coarse aggregates, controlling the economic cost and the like.
The demonstration process of the fitting formula in the above embodiment is as follows:
the water absorption and crush values of red bricks, mortar and old concrete (i.e., old concrete) in a test (designated as test 1) are shown in the following table.
| Components | Water absorption% | Crush value% |
| Red brick | 21.6 | 31.8 |
| Mortar | 12.8 | 25.4 |
| Old concrete | 7·8 | 19·6 |
Since the water absorption and crushing values corresponding to the three components are given in the table, six components with different proportions can be artificially selected and matched, and then the corresponding water absorption and crushing values can be calculated according to the matching of the components, and the artificially matched six components with different proportions and the calculated water absorption and crushing values can be regarded as a simulation of i parts (i is equal to 6) of the test construction waste recycled coarse aggregate in the invention.
Specifically, when six components with different proportions are artificially matched, the total content P of the red bricks and the mortar can be directly calculated according to the proportion of each component (the proportion of the red bricks, the proportion of the mortar and the proportion of the old concrete); moreover, since the water absorption and crushing value corresponding to each component are known, and the proportion of each component (red brick proportion, mortar proportion and old concrete proportion) is combined, the water absorption W of the mixture consisting of the red bricks, the mortar and the old concrete on the whole can be calculatedxAnd crush value Qa。
As shown in the following table, the data corresponding to samples 1-6 were calculated based on the different ratios of the components in 6 and the corresponding data in test 1, which were recorded as samples 1-6.
For comparison, the P value and w value in the above table are shown in formula 1 and formula 2, respectivelyxValue, QaFitting the values, wherein formula 1 is a comparison formula, and formula 2 is a formula in the invention.
First, by equation 1: p ═ a + bwx+cQaFor the P value, w in the above tablexValue, QaFitting the values to a fitting degree R2Is 1, a is about-643.70, b is about-33.61, and c is about 46.22.
Then, by equation 2: p ═ a × wx b×Qa cFitting to the P value, w in the above tablexValue, QaFitting the values to a fitting degree R2About 0.99, a about 18455.24, b about 5.23, and c about-6.14.
Re-selecting 3 groups of components with different proportions for collocation, recording as test 1, test 2 and test 3 based on the corresponding data in test 1, and recording the related data (P value, w value) of test 1-3xValue, QaValues), the results of which are shown in the following table:
samples 1-6 and w in tests 1-3xValue and QaSubstituting the values into the formula 1, respectively calculating the P value by combining the parameters a, b and c of the formula 1, and then comparing the difference value between the calculated value of the P value and the theoretical calculation value. By comparison, in the case of calculation by equation 1, the calculated value of P is the same as the calculated value by 0 for samples 1 to 6 and tests 1 to 3.
Samples 1-6 and w in tests 1-3xValue and QaSubstituting the values into the formula 2, respectively calculating the P value by combining the parameters a, b and c of the formula 2, and then comparing the difference value between the calculated value of the P value and the theoretical calculation value. By comparison, in the case of calculation by equation 2, the difference between the calculated value and the estimated value of the P value based on the samples 1 to 6 and the tests 1 to 3 is shown in the following table:
it can be seen that the accuracy of equation 1 is better than that of equation 2 based on experiment 1, but since the parameters a, b, and c in equation 1 and equation 2 are obtained by fitting based on the data in experiment 1, the applicability of equation 1 and equation 2 in other batches needs to be judged.
The water absorption and crush values for red brick, mortar, and old concrete (i.e., old concrete) in another test (identified as test 2) are shown in the following table:
| components | Water absorption% | Crush value% |
| Red brick | 17.28 | 25.44 |
| Mortar | 10.24 | 20.32 |
| Old concrete | 6.24 | 15.68 |
Matching the components according to the proportion of test 1, test 2 and test 3, marking the data corresponding to the test 2 as test 4, test 5 and test 6, and carrying out the data (P value and w value) related to the test 4-6xValue, QaValues), the results of which are shown in the following table:
w in tests 4 to 6 will be testedxValue and QaSubstituting the values into the formula 1, respectively calculating the P value by combining the parameters a, b and c of the formula 1, and then comparing the difference value between the calculated value of the P value and the theoretical calculation value. By comparison, in the case of calculation by equation 1, the difference between the calculated and extrapolated values of the P value based on tests 4-6 is shown in the following table:
| group of | Calculated value of P value | Estimated value of P value | Difference value |
| Test 4 | -121 | 10 | -131 |
| Test 5 | -101 | 35 | -136 |
| Test 6 | -90 | 48 | -138 |
W in tests 4 to 6 will be testedxValue and QaSubstituting the values into the formula 2, respectively calculating the P value by combining the parameters a, b and c of the formula 2, and then comparing the difference value between the calculated value of the P value and the theoretical calculation value. By comparison, in the case of calculation by equation 2, the difference between the calculated and extrapolated values of the P value based on tests 4-6 is shown in the following table:
| group of | Calculated value of P value | Estimated value of P value | Difference value |
| Test 4 | 17 | 10 | 7 |
| Test 5 | 34 | 35 | -1 |
| Test 6 | 48 | 48 | 0 |
In summary, it can be known that the fitting accuracy of equation 1 to the construction waste from a single source is higher than that of equation 2 proposed in this patent, but the material performance of the construction waste is unstable and has great variability, and equation 2 can better fit the detection data from one batch of materials to obtain the equation parameters a, b, and c, and can be applied to the calculation of other batches.
As a further explanation of the above embodiment, it should be noted that, in order to ensure that the formula P ═ a × wx b×Qa cThe accuracy of the fitting, in the step S3, is determined according to the formula P ═ a × wx b×Qa cFitting the median P value, w, of said S2xValue, QaDegree of fit R of value2The requirement is more than or equal to 0.85.
In order to ensure the preparation of coarse aggregate, in step S1, when the test construction waste recycled coarse aggregate is obtained, the particle sizes of the bricks, the mortar and the concrete blocks are all larger than 4.75mm, i.e. the bricks, the mortar and the concrete blocks need to pass through a 4.75mm square-hole sieve before different test construction waste recycled coarse aggregates are configured. It should be noted that there may be mortar in the form of mortar blocks, and some mortar may be attached to the concrete blocks, and the mortar attached to the concrete blocks may be sieved together with the concrete blocks.
In order to facilitate configuration, detection and fitting calculation, in the step S1, raw materials of each of the i test building waste recycled coarse aggregates are all derived from the same batch; and in the i parts of the coarse aggregate regenerated by the test construction waste, the proportion of the bricks of different parts of the coarse aggregate regenerated by the test construction waste can be increased in an equal difference mode.
As an explanation of the method for detecting the total content of the bricks and the mortar, when the total content of the bricks and the mortar is detected, a sample can be divided into two parts for standby application by reducing the sample to the required quality in the following table.
| Nominal maximum particle size (mm) | 9.5 | 19 | 26.5 | 31.5 | 37.5 |
| Minimum number of samples (kg) for total content test of brick and mortar | 35 | 55 | 55 | 75 | 75 |
Obtaining the content of the bricks through manual separation, obtaining the content of the mortar through high-temperature treatment and the like, and calculating the total content P of the bricks and the mortar.
It is noted that when the water absorption of the reclaimed coarse aggregates is measured by using the test method of aggregate test for road engineering (JTG E42-2005) T0308, it is found that the reclaimed coarse aggregates are difficult to dry to constant weight in a short time and there is a certain loss of mass of the coarse aggregates when the surfaces of the particles are wiped with a wringed wet towel.
In order to accurately measure the water absorption rate of the regenerated coarse aggregate to obtain a fitting parameter of a calculation formula, the water absorption rate wxThe detection method comprises the following steps:
s21, preprocessing; wherein the pretreatment comprises soaking a sample in water and weighing at the early stage;
the sample immersion includes: selecting a sample from the construction waste regenerated coarse aggregate to be detected, dividing the sample, and soaking the sample in water to obtain a soaking sample;
the earlier stage weighing comprises: weighing the total mass m of the dried water-absorbing material and the container1；
S22, taking the soaking sample, removing free water on the soaking sample, wiping the surface water of the soaking sample by the water-absorbing material which is soaked and wrung to obtain a saturated face-dry sample and a used water-absorbing material, and weighing the mass m of the saturated face-dry sample3；
S23, drying the saturated dried noodle sample to obtain a dried sample, and weighing the mass m of the dried sample0(ii) a Putting the used water absorbent into the containing container for drying, and weighing the total mass m of the used water absorbent and the containing container after drying2；
S24 according to the formula
Calculating the water absorption wx。
In the above embodiment, in order to ensure the sufficiency of immersing the sample in water, in step S21, the water level of the sample in the immersion is preferably higher than the top surface height of the sample; the soaking time of the sample in water is not less than 24 h.
In addition, in order to ensure the consistency of the front and back drying and improve the detection accuracy of the water absorption rate, the step S21 and the step S23 are consistent in the drying temperature, and the drying temperature is 105 ℃ ± 5 ℃.
As a water absorption rate wxIn the detection method (3), the water absorption rate w is measuredxIn the process, the sample can be reduced to the quality required by the following table by a quartering method or a distributor method, and the sample is divided into two parts for standby.
| Nominal maximum particle size (mm) | 4.75 | 9.5 | 16 | 19 | 26.5 | 31.5 | 37.5 | 63 | 75 |
| Water absorption test minimum mass (kg) | 0.8 | 1 | 1 | 1 | 1.5 | 1.5 | 2 | 3 | 3 |
It should be noted that each sample was soaked in water before the water absorption test, and the dust and stone powder attached to the aggregate surface were carefully washed off and rinsed many times until the water was clear. The aggregate particles must not be lost during the cleaning process. Due to the water absorption rate wxThe detection belongs to a detection method after improvement, so, the detection method is described in more detail by way of example, and specific test steps can include:
1. and (3) putting one sample into a container containing water, enabling the water surface to be about 5mm higher than the surface of the sample, and taking out the sample from the water after 24 hours.
2. Placing several clean towels into a tray, drying in an oven at 105 + -5 deg.C to constant weight, cooling, and weighing mass (m)1) Then the towel is soaked, wrung out and laid flat in a tray.
3. Pouring the sample into a shallow enamel tray, slightly tilting the enamel tray, pouring out the flowing water, and then sucking the leaked free water by using a towel.
4. And (3) lightly wiping the surface water of the particles by using a wringed wet towel until no bright water stains can be seen on the surface, namely the saturated face dry state. When the coarse aggregate size is large, it can be wiped dry particle by particle. Care should be taken not to apply too much force when wringing the towel, to prevent wringing too dry. When the surface water of the particles is wiped, the surface water is wiped off, and the water in the particles cannot be sucked out. In the whole process, no aggregate falls outside the tray, and the wet tissue is wiped and then placed in the tray.
5. The surface dry mass (m) of the saturated dried aggregate (i.e. saturated dried sample) is immediately weighed3)。
6. Putting the aggregate in a shallow tray, and putting the shallow tray in an oven with the temperature of 105 +/-5 ℃ for drying for not less than 24 hours. Taking out the tray, placing in a container with a cover, cooling to room temperature, and weighing the oven-dried mass (m) of the aggregate (i.e. oven-dried sample)0)。
7. Putting the wiped towel and the tray into a drying oven at 105 +/-5 ℃ to dry to constant weight, cooling and weighing mass (m)2)。
Water absorption w of aggregatexBased on the dried sample, the accuracy is up to 0.1% by the following formula.
In connection with the analysis of the specific case, the symbols in the formula can be understood as:
wx-water absorption (%) of the construction waste recycled coarse aggregate;
m0-drying quality (g) of construction waste recycled coarse aggregate;
m1-drying mass (g) of clean towels and trays;
m2-drying mass (g) of towel and tray after wiping;
m3-surface dry mass (g) of construction waste recycled coarse aggregate.
The precision of the test is repeated, and the difference between the two results is not more than 0.2%.
It will be appreciated by those skilled in the art that the crush value Q is described in the practice of the inventionaThe detection method comprises the following steps: sampling from the construction waste regeneration coarse aggregate to be tested, and sieving to obtain a sample with the grain size of 9.5-13.2 mm; the crushing value Q is carried out after the samples with the grain diameter specification of 9.5 mm-13.2 mm are reduced to the preset qualityaThe detection test of (3).
In particular, the crushingValue QaThe method of (3) can be expressed as that samples are sequentially screened by 13.2mm and 9.5mm standard sieves, and 3000g of 9.5mm to 13.2mm samples are respectively taken for testing. Then obtaining a crushing value Q according to a standard test method T0316ai。
It should be noted that, in order to further optimize the parameters a, b, c in the present invention, the method for evaluating and detecting the construction waste recycled coarse aggregate further includes the following steps:
s5, continuously carrying out the total content P of the bricks and the mortar and the water absorption w on the subsequent construction waste regenerated coarse aggregatexAnd the crush value QaAnd supplementing the data of the detection test of the subsequent construction waste recycled coarse aggregate into the fitting of the step S3, thereby optimizing the parameters a, b, c. Wherein, the total content P of the bricks and the mortar and the water absorption w are carried out on the subsequent samplesxAnd the crush value QaThe detection test of (1) can obtain the corresponding P value and w valuexValue, QaValues, and thus used to optimize the parameters a, b, c in the fitting equation.
It should be noted that in the above embodiments, the methods adopted by the test construction waste reclaimed coarse aggregate and the construction waste reclaimed coarse aggregate to be evaluated in the detection are consistent. And the test construction waste regenerated coarse aggregate and the construction waste regenerated coarse aggregate to be evaluated are only one of the sequence, and both are essentially the construction waste regenerated coarse aggregate and contain bricks, mortar and concrete blocks.
The invention also provides a classification method of the construction waste recycled coarse aggregate, which comprises the steps of obtaining the total content P of bricks and mortar of the construction waste recycled coarse aggregate to be evaluated according to the evaluation detection method of any embodiment, and classifying the construction waste recycled coarse aggregate to be evaluated according to the total content P of the bricks and the mortar of the construction waste recycled coarse aggregate to be evaluated after obtaining the total content P of the bricks and the mortar of the construction waste recycled coarse aggregate to be evaluated.
In the above technical solutions, the above are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and all the technical solutions of the present invention that are directly or indirectly applied to other related technical fields and the equivalent structural changes made by the present specification are included in the scope of the present invention.
Claims (10)
1. An assessment and detection method for construction waste regenerated coarse aggregate is characterized by comprising the following steps:
s1, obtaining i parts of test construction waste recycled coarse aggregate; the i is more than or equal to 5, the test construction waste regenerated coarse aggregate comprises bricks, mortar and concrete blocks, and the proportion of the bricks of each test construction waste regenerated coarse aggregate is different;
s2, detecting the P value and w value of each test construction waste regenerated coarse aggregatexValue, and QaA value; wherein P is the total content of bricks and mortar, and wxFor water absorption, said QaIs the crush value;
s3, according to formula P ═ a × wx b×Qa cFitting the P value, w in S2xValue, QaObtaining parameters a, b and c;
s4, detecting the water absorption w of the construction waste regenerated coarse aggregate to be evaluatedxAnd crush value QaThen, based on the parameters a, b, c obtained in S3 and the formula P ═ a × wx b×Qa cAnd obtaining the total content P of the bricks and the mortar of the construction waste recycled coarse aggregate to be evaluated.
2. The method for evaluating and detecting coarse aggregate reclaimed from construction waste according to claim 1, wherein in step S3, the method is according to the formula P ═ a × wx b×Qa cFitting the median P value, w, of said S2xValue, QaDegree of fit R of value2≥0.85。
3. The method for evaluating and testing construction waste recycled coarse aggregate according to claim 1, wherein in step S1, the particle sizes of the brick, mortar and concrete block are all larger than 4.75mm when the test construction waste recycled coarse aggregate is obtained.
4. The method for evaluating and testing construction waste reclaimed coarse aggregates according to claim 1, wherein in the step S1, raw materials of each sample construction waste reclaimed coarse aggregate in the i test construction waste reclaimed coarse aggregates are all from the same batch;
and in the i parts of the coarse aggregate regenerated by the test construction waste, the proportion of the bricks of different parts of the coarse aggregate regenerated by the test construction waste is increased in an equal difference mode.
5. The method for evaluating and detecting the construction waste recycled coarse aggregate according to claim 1, wherein the method for detecting the water absorption rate comprises the following steps:
s21, preprocessing; wherein the pretreatment comprises soaking a sample in water and weighing at the early stage;
the sample immersion includes: selecting a sample from the construction waste regenerated coarse aggregate to be detected, dividing the sample, and soaking the sample in water to obtain a soaking sample;
the earlier stage weighing comprises: weighing the total mass m of the dried water-absorbing material and the container1；
S22, taking the soaking sample, removing free water on the soaking sample, wiping the surface water of the soaking sample by the water-absorbing material which is soaked and wrung to obtain a saturated face-dry sample and a used water-absorbing material, and weighing the mass m of the saturated face-dry sample3；
S23, drying the saturated dried noodle sample to obtain a dried sample, and weighing the mass m of the dried sample0(ii) a Putting the used water absorbent into the containing container for drying, and weighing the total mass m of the used water absorbent and the containing container after drying2；
S24 according to the formula
Calculating the water absorption wx。
6. The method for evaluating and detecting coarse aggregates recycled by construction wastes according to claim 5, wherein in the step S21, the water level of the specimen is higher than the top surface height of the specimen when the specimen is immersed; the soaking time of the sample in water is not less than 24 h.
7. The method for evaluating and testing the construction waste recycled coarse aggregate of claim 5, wherein the step S21 and the step S23 are consistent in drying temperature, and the drying temperature is 105 ℃ ± 5 ℃.
8. The evaluation and detection method for the construction waste recycled coarse aggregate according to claim 1, wherein the crushing value Q isaThe detection method comprises the following steps: sampling from the construction waste regeneration coarse aggregate to be tested, and sieving to obtain a sample with the grain size of 9.5-13.2 mm; the crushing value Q is carried out after the samples with the grain diameter specification of 9.5 mm-13.2 mm are reduced to the preset qualityaThe detection test of (3).
9. The evaluation and detection method for the construction waste recycled coarse aggregate according to any one of claims 1 to 8, further comprising the steps of:
s5, continuously carrying out the total content P of the bricks and the mortar and the water absorption w on the subsequent construction waste regenerated coarse aggregatexAnd the crush value QaAnd supplementing the data of the detection test of the subsequent construction waste recycled coarse aggregate into the fitting of the step S3.
10. A classification method of construction waste recycled coarse aggregate, characterized in that the total content P of bricks and mortar of the construction waste recycled coarse aggregate to be evaluated is obtained according to the evaluation detection method of any one of claims 1 to 9, and the construction waste recycled coarse aggregate to be evaluated is classified according to the total content P of bricks and mortar of the construction waste recycled coarse aggregate to be evaluated.
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