CN114720498A - Method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregate - Google Patents
Method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregate Download PDFInfo
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- 239000004567 concrete Substances 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 52
- 239000004570 mortar (masonry) Substances 0.000 title claims abstract description 42
- 238000012360 testing method Methods 0.000 claims abstract description 161
- 238000010183 spectrum analysis Methods 0.000 claims abstract description 24
- 238000004876 x-ray fluorescence Methods 0.000 claims abstract description 24
- 238000002441 X-ray diffraction Methods 0.000 claims abstract description 12
- 238000005070 sampling Methods 0.000 claims abstract description 12
- 239000000126 substance Substances 0.000 claims abstract description 6
- 238000004088 simulation Methods 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 230000006378 damage Effects 0.000 claims description 15
- 238000009835 boiling Methods 0.000 claims description 12
- 238000001816 cooling Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000004458 analytical method Methods 0.000 claims description 5
- 238000005553 drilling Methods 0.000 claims description 5
- 230000001681 protective effect Effects 0.000 claims description 5
- 229920006395 saturated elastomer Polymers 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 4
- 238000012795 verification Methods 0.000 claims description 4
- 230000009286 beneficial effect Effects 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 3
- 230000007547 defect Effects 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 3
- 238000007689 inspection Methods 0.000 claims description 3
- 239000003550 marker Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 238000007873 sieving Methods 0.000 claims description 3
- 230000006835 compression Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 239000008187 granular material Substances 0.000 claims 2
- 238000001514 detection method Methods 0.000 abstract description 5
- 239000004566 building material Substances 0.000 abstract description 2
- 238000002955 isolation Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/223—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20008—Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor
- G01N23/2005—Preparation of powder samples therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/207—Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/2202—Preparing specimens therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/225—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion
- G01N23/2251—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion using incident electron beams, e.g. scanning electron microscopy [SEM]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0003—Steady
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0284—Bulk material, e.g. powders
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/0641—Indicating or recording means; Sensing means using optical, X-ray, ultraviolet, infrared or similar detectors
- G01N2203/0647—Image analysis
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
A method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregate belongs to a detection method of building materials, and comprises the steps of carrying out on-site sampling, then carrying out indoor test, X-ray fluorescence spectrum analysis test, simulation test under specific environment, X-ray diffraction test and scanning electron microscope test, analyzing the influence degree of the problematic aggregate, and finally verifying treatment protection measures. According to the method, through analyzing the aspects of chemical components, phases, microstructures and the like of suspicious problem aggregates at the self-collapsing part on the surface of the concrete and in the concrete, unreacted problem aggregates are found out, the problem aggregates are judged, the source of the problem aggregates is judged according to actual conditions, the process, environment and mechanism of the self-collapsing phenomenon are analyzed, the influence degree of the problem aggregates on engineering entities is judged, and reasonable treatment and protection suggestions are given.
Description
Technical Field
The invention belongs to the technical field of building material detection methods, and particularly relates to the technical field of methods for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregates.
Background
With the development and progress of society, people newly build a large number of concrete structures every year, so that the demand of society on the main component aggregate of concrete is always large, people are also used to easily and directly ask for the aggregate from the nature, and with the national emphasis on ecological environment protection, the mining of the aggregate for concrete or mortar is more and more strictly limited, and some aggregates which are originally not suitable for concrete or mortar are intentionally or unintentionally used for production, so that the phenomenon of self-collapse of hardened concrete or mortar is increased year by year, the safety and the appearance of the concrete structures are greatly damaged, and a plurality of social contradictions are caused. At present, no detection and analysis method aiming at the phenomenon exists in China.
Disclosure of Invention
The invention provides a method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregate, which is used for analyzing the problematic aggregate causing the self-collapse phenomenon of the hardened concrete or mortar, further judging the influence degree of the problematic aggregate on engineering entities and providing reasonable treatment and protection suggestions.
The specific technical scheme is as follows:
a method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregate comprises the following steps:
step one, sampling on site;
step two, performing indoor test;
step three, X-ray fluorescence spectrum analysis test;
step four, simulating a test in a specific environment;
step five, performing an X-ray diffraction test;
step six, scanning electron microscope test;
analyzing the influence degree of the problematic aggregate;
and step eight, processing protective measure verification.
Preferably, the specific process of on-site sampling in the first step of the invention is as follows:
sampling the self-collapsing part by adopting a core drilling method or a cutting method, and sealing and protecting the self-collapsing part of the hardened concrete or mortar before coring or cutting; or stripping particulate or powdery suspicious objects in the self-collapsing part on site; the removed core or test block is marked and photographed.
Preferably, the specific process of the indoor test in the second step of the invention is as follows:
the auto-collapsed site on the retrieved core sample was measured for size and photographed and mixed with the suspected auto-collapsed site extracted on site and ground and sieved through a 0.075mm square mesh sieve to make sample 1.
Preferentially, the specific process of the X-ray fluorescence spectrum analysis test in the third step of the invention is as follows:
carrying out an X-ray fluorescence spectrum analysis test on the sample 1, and recording the result as fluorescence 1; cutting a part of the retrieved concrete core sample into a sheet with the thickness of 1cm or cutting a part of the retrieved mortar test block into a strip with the width of 1cm, performing an X-ray fluorescence spectrum analysis test on the position of the suspicious aggregate in the cutting surface, comparing the result with the fluorescence 1, recording the approximate result as fluorescence 0, and marking by using a marker pen;
randomly taking three concrete core samples or mortar test blocks, preparing the core samples or the mortar test blocks into particles by a press and/or a hammer, picking out aggregates which can cause the problem of self-collapse of hardened concrete or mortar, carrying out an X-ray fluorescence spectrum analysis test, putting the aggregates with the result similar to that of fluorescence 1 together, crushing and grinding the aggregates, sieving the crushed aggregates with a square-hole sieve of 0.075mm to prepare a sample 2, and carrying out the X-ray fluorescence spectrum analysis test, wherein the result is marked as fluorescence 2.
Preferentially, the simulation test in the specific environment in the fourth step of the invention comprises the following specific processes:
placing the sheet or strip test piece subjected to the X-ray fluorescence spectrum analysis test into a water bath pot, heating to boil, boiling for 6h, and naturally cooling to room temperature; observing the marking point and the whole damage condition of the test piece after boiling, taking a picture and recording, placing the test piece in a natural dry state, and then carrying out an X-ray fluorescence spectrum analysis test on the substances in the damage point again, wherein if the damage point does not exist, the result is recorded as fluorescence 0-0;
and comparing and analyzing the relation between fluorescence 0 and fluorescence 0-0, between fluorescence 2 and fluorescence 1, and between fluorescence 0-0 and fluorescence 1, determining and finding out the unreacted problem aggregate, and recording and analyzing the self-collapse condition of the aggregate at the identification point.
Preferentially, the specific process of the X-ray diffraction test in the fifth step of the invention is as follows:
the X-ray diffraction tests were performed on sample 1 and sample 2, respectively, and the results were XRD1 and XRD2, respectively, and the relationship between the two and the process of interconversion formation were analyzed.
Preferentially, the specific process of the scanning electron microscope test in the sixth step of the invention is as follows:
SEM tests are respectively carried out on the suspicious reacted materials and the suspicious unreacted aggregates at the self-collapsing part, and the analysis test results of X-ray diffraction are verified from the microscopic morphology.
Preferentially, the concrete process of analyzing the influence degree of the problematic aggregate in the seventh step of the invention is as follows:
randomly selecting 16 core samples or test blocks, wherein 10 core samples or test blocks are respectively cut into two 10 mm-thick sheet-shaped or 10 mm-wide strip-shaped test pieces without appearance defects, and 20 test pieces are taken in total and subjected to appearance photographing; carrying out a compression strength test on the remaining 6 core samples or test blocks, wherein 3 core samples or test blocks are used as comparison test pieces;
respectively placing 3 core samples or test blocks and 20 test pieces into a water bath kettle, heating to boil, boiling for 6h, naturally cooling to room temperature, standing to natural dry state, and respectively detecting and comparing the compressive strength of the sample
And the compressive strength of the test specimen
，
Calculating the change rate of the compressive strength before and after the test according to the formula (1)
(ii) a Carrying out appearance inspection and photographing, comparing with the photo before the test, and counting the number of the damaged test pieces after 20 test pieces are boiled
Calculating the self-collapse failure rate of the problematic aggregate according to the formula (2)
(ii) a The change rate of the compressive strength before and after the test
And problem of self-collapse failure rate of aggregate
As the basis for judging the influence degree of the problematic aggregate on the hardened concrete or mortar.
Preferentially, the specific process for processing the safeguard verification in the step eight of the invention is as follows:
the method comprises the steps of taking 18 core samples or strip-shaped test blocks from the core samples or test blocks taken back on site, putting the core samples or strip-shaped test blocks into test block boxes respectively, putting the test block boxes in six environments of natural drying and air isolation, natural drying and air contact, surface wetting and air isolation, surface wetting and air contact, water saturation and air isolation, water saturation and air contact respectively for testing, 3 test blocks in each environment, putting the test block boxes into a water bath, raising the temperature to 100 +/-2 ℃ from the room temperature, boiling for 6 hours, naturally cooling to the room temperature, checking and recording the damage condition of the test blocks in each environment, and judging which environment is most beneficial and most harmful to the intact state of the test blocks according to the damage condition of the test blocks, so that reasonable treatment and protection suggestions are given.
By adopting the technical scheme, compared with the prior art, the invention has the advantages that: through the analysis of the aspects of chemical compositions, phases, microstructures and the like of suspicious problem aggregates at the self-collapsing part of the concrete surface and in the concrete, unreacted problem aggregates are found out, the problem aggregates are distinguished, the source of the problem aggregates is distinguished by combining with the actual situation, the process, the environment and the mechanism of the self-collapsing phenomenon are analyzed, the influence degree of the problem aggregates on engineering entities is judged, and reasonable treatment and protection suggestions are given.
Detailed Description
A method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregates comprises the following steps:
step one, field sampling:
(1) sampling the self-collapsing part by adopting a core drilling method or a cutting method, and sealing and protecting the self-collapsing part of hardened concrete or mortar before coring or cutting in order to reduce the pollution (mainly dust and water) to suspicious objects during coring or cutting; when the core drilling method is adopted, the proposal is that: the core sample diameter is 70mm, core on the concrete slab, the degree of depth is the thickness of board, and will avoid the reinforcing bar. When the cutting method is adopted, the cutting size of the sampling suggests that: length × width =100mm × 100 mm.
(2) And (3) stripping granular or powdery suspicious objects in the self-collapsing part in situ. During sampling, the sampling part is required to be recorded and photographed, and then the taken core sample or test block is marked and photographed.
Step two, indoor test:
the auto-collapsed sites on the retrieved core samples were measured for size (length, width and depth) and photographed and mixed with the suspected auto-collapsed site extracted on site and ground and sieved through a 0.075mm square mesh sieve to produce sample 1.
Step three, X-ray fluorescence spectrum analysis test:
carrying out an X-ray fluorescence spectrum analysis test on the sample 1, and recording the result as fluorescence 1; cutting a part of the retrieved concrete core sample into a sheet with the thickness of 1cm or cutting a part of the retrieved mortar test block into a strip with the width of 1cm, performing an X-ray fluorescence spectrum analysis test on the position of the suspicious aggregate in the cutting surface, comparing the result with the fluorescence 1, recording the approximate result as fluorescence 0, and marking by using a marker pen;
randomly taking three concrete core samples or mortar test blocks, preparing the core samples or the mortar test blocks into particles by a press machine and/or a hammer, picking out aggregates which can cause self-collapse of hardened concrete or mortar from the particles, carrying out an X-ray fluorescence spectrum analysis test, putting the aggregates with the result similar to that of fluorescence 1 together, crushing and grinding the aggregates, and sieving the crushed aggregates through a square-hole sieve of 0.075mm to prepare a sample 2, and carrying out the X-ray fluorescence spectrum analysis test, wherein the result is marked as fluorescence 2.
Step four, simulation test under specific environment:
the test is carried out according to a method of ' detection inference of potential hazards of free calcium oxide ' in annex G of building structure detection technical Standard ' (GB/T50344-2019). And (3) putting the sheet or strip test piece subjected to the X-ray fluorescence spectrum analysis test into a water bath pot, heating to boil, boiling for 6h, and naturally cooling to room temperature. And observing the marking point and the whole damage condition of the test piece after boiling, taking a picture and recording, placing the test piece in a natural dry state, performing an X-ray fluorescence spectrum analysis test on the substances in the damage point again, and if the damage point does not exist, marking the result as fluorescence 0-0.
And comparing and analyzing the relation between fluorescence 0 and fluorescence 0-0, between fluorescence 2 and fluorescence 1, and between fluorescence 0-0 and fluorescence 1, determining and finding out the unreacted problem aggregate, and recording and analyzing the self-collapse condition of the aggregate at the identification point.
Step five, X-ray diffraction test:
the X-ray diffraction tests were carried out on sample 1 and sample 2, respectively, and the results were XRD1 and XRD2, respectively, and the relationship between the two was analyzed, as well as the process of interconversion formation.
Step six, scanning electron microscope test:
SEM tests are respectively carried out on the suspicious reacted materials and the suspicious unreacted aggregates at the self-collapsing part, and the analysis test results of X-ray diffraction are verified from the microscopic morphology.
Step seven, analyzing the influence degree of the problematic aggregate:
randomly selecting 16 core samples or test blocks, respectively cutting two 10mm thick sheet-shaped or 10mm wide strip-shaped test pieces without appearance defects from 10 core samples or test blocks, totaling 20 test pieces, and performing appearance photographing. And (3 of the 6 core samples or test blocks are used as comparison test pieces), the concrete core samples are subjected to compressive strength test according to the technical specification for detecting the concrete strength by a core drilling method JGJ/T384-plus 2016, and the mortar test blocks are subjected to compressive strength test according to the technical specification for detecting the compressive strength of the hardened mortar by an impact method YB 9248-plus 1992.
And respectively putting the 3 core samples or test blocks and the 20 test pieces into a water bath kettle, heating to boil, boiling for 6 hours, and naturally cooling to room temperature. After the sample is placed to a natural dry state, the compressive strength of the sample is detected and compared for at least 3 days
And the compressive strength of the test specimen
，
Calculating the change rate of the compressive strength before and after the test according to the formula (1)
(ii) a Carrying out appearance inspection and photographing, comparing with the photo before the test, and counting the number of the damaged test pieces after 20 test pieces are boiled
Calculating the self-collapse failure rate of the problematic aggregate according to the formula (2)
(ii) a The change rate of the compressive strength before and after the test
And problem of self-collapse failure rate of aggregate
As the basis for judging the influence degree of the problematic aggregate on the hardened concrete or mortar.
Step eight, processing protective measure verification:
according to the mechanism of the self-collapse phenomenon, whether the hardened concrete or mortar can be subjected to self-collapse under different environments is simulated, so that the influence degree of the environment (mainly water and air) on the self-collapse of the hardened concrete or mortar is judged, and a reasonable treatment protective measure suggestion is provided according to the influence degree.
Respectively taking 18 core samples (recommended diameter is 25 mm) or strip-shaped test blocks (recommended width is 20 mm) from the core samples or test blocks taken back on site, respectively putting the core samples or test blocks into test block boxes, respectively putting the test blocks into six environments which are naturally dry and air-isolated, naturally dry and in contact with air, moist in appearance and air-isolated, moist in appearance and in contact with air, saturated in water and air-isolated, saturated in water and air-saturated, and in contact with air, respectively testing 3 test blocks in each environment, then putting the test block boxes into a water bath, raising the temperature from room temperature to 100 +/-2 ℃, after constant boiling for 6 hours, naturally cooling to room temperature, checking and recording the damage condition of the test blocks in each environment, and judging which environment is most beneficial and harmful to the test blocks to keep the intact states according to the damage condition of the test blocks, thereby giving a reasonable treatment protection suggestion.
According to the method, through analyzing the aspects of chemical components, phases, microstructures and the like of suspicious problem aggregates at the self-collapsing part on the surface of the concrete and in the concrete, unreacted problem aggregates are found out, the problem aggregates are distinguished, the source of the problem aggregates is distinguished by combining with the actual situation, the process, the environment and the mechanism of the self-collapsing phenomenon are analyzed, the influence degree of the problem aggregates on the engineering entity is judged, and reasonable treatment and protection suggestions are given.
Claims (9)
1. A method for detecting and analyzing self-collapse of hardened concrete or mortar caused by problematic aggregate is characterized by comprising the following steps:
step one, sampling on site;
step two, performing indoor test;
step three, X-ray fluorescence spectrum analysis test;
step four, simulating a test in a specific environment;
step five, performing an X-ray diffraction test;
step six, scanning electron microscope test;
analyzing the influence degree of the problematic aggregate;
and step eight, processing protective measure verification.
2. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 1, wherein the concrete process of on-site sampling in the first step is as follows:
sampling the self-collapsing part by adopting a core drilling method or a cutting method, and sealing and protecting the self-collapsing part of the hardened concrete or mortar before coring or cutting; or stripping particulate or powdery suspicious objects in the self-collapsing part on site; the removed core or test block is marked and photographed.
3. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 2, wherein the specific process of the indoor test in the second step is as follows:
the auto-collapsed site on the retrieved core sample was measured for size and photographed and mixed with the suspected auto-collapsed site extracted on site and ground and sieved through a 0.075mm square mesh sieve to make sample 1.
4. The method for detecting and analyzing problem aggregate to cause self-collapse of hardened concrete or mortar according to claim 3, wherein the X-ray fluorescence spectrum analysis test in the third step comprises the following specific processes:
carrying out an X-ray fluorescence spectrum analysis test on the sample 1, and recording the result as fluorescence 1; cutting a part of the retrieved concrete core sample into a sheet with the thickness of 1cm or cutting a part of the retrieved mortar test block into a strip with the width of 1cm, performing an X-ray fluorescence spectrum analysis test on the position of the suspicious aggregate in the cutting surface, comparing the result with the fluorescence 1, recording the approximate result as fluorescence 0, and marking by using a marker pen;
randomly taking three concrete core samples or mortar test blocks, preparing the three concrete core samples or mortar test blocks into granules, selecting aggregates which can cause the problem of self-collapse of hardened concrete or mortar from the granules, carrying out an X-ray fluorescence spectrum analysis test, putting the result together with the aggregates with similar fluorescence 1, crushing and grinding the aggregates, sieving the crushed aggregates through a square-hole sieve with the thickness of 0.075mm to prepare a sample 2, carrying out the X-ray fluorescence spectrum analysis test, and marking the result as fluorescence 2.
5. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 4, wherein the simulation test in the specific environment in the fourth step comprises the following specific processes:
placing the sheet or strip test piece subjected to the X-ray fluorescence spectrum analysis test into a water bath pot, heating to boil, boiling for 6h, and naturally cooling to room temperature; observing the mark point and the whole damage condition of the test piece after boiling, taking a picture and recording, placing the test piece in a natural dry state, and performing an X-ray fluorescence spectrum analysis test on the substances in the damage point again, wherein the result is marked as fluorescence 0-0;
and comparing and analyzing the relation between fluorescence 0 and fluorescence 0-0, between fluorescence 2 and fluorescence 1, and between fluorescence 0-0 and fluorescence 1, determining and finding out the unreacted problem aggregate, and recording and analyzing the self-collapse condition of the aggregate at the identification point.
6. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 5, wherein the X-ray diffraction test in the fifth step comprises the following specific processes:
the X-ray diffraction tests were performed on sample 1 and sample 2, respectively, and the results were XRD1 and XRD2, respectively, and the relationship between the two and the process of interconversion formation were analyzed.
7. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 6, wherein the specific process of the scanning electron microscope test in the sixth step is as follows:
SEM tests are respectively carried out on the suspicious reacted materials and the suspicious unreacted aggregates at the self-collapsing part, and the analysis test results of X-ray diffraction are verified from the microscopic morphology.
8. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 7, wherein the concrete process of analyzing the influence degree of the problem aggregate in the seventh step is as follows:
randomly selecting 16 core samples or test blocks, wherein 10 core samples or test blocks are respectively cut into two 10 mm-thick sheet-shaped or 10 mm-wide strip-shaped test pieces without appearance defects, and 20 test pieces are taken in total and subjected to appearance photographing; carrying out compression strength tests on the remaining 6 core samples or test blocks, wherein 3 of the core samples or test blocks are used as comparison test pieces;
respectively placing 3 core samples or test blocks and 20 test pieces into a water bath kettle, heating to boil, boiling for 6h, naturally cooling to room temperature, standing to natural dry state, and respectively detecting and comparing the compressive strength of the sample
And the compressive strength of the test specimen
，
Calculating the change rate of the compressive strength before and after the test according to the formula (1)
(ii) a Carrying out appearance inspection and photographing, comparing with the photo before the test, and counting the number of the damaged test pieces after 20 test pieces are boiled
Calculating the self-collapse failure rate of the problematic aggregate according to the formula (2)
(ii) a The change rate of the compressive strength before and after the test
And problem of self-collapse destruction rate of aggregate
As the basis for judging the influence degree of the problematic aggregate on the hardened concrete or mortar.
9. The method for detecting and analyzing problem aggregate causing self-collapse of hardened concrete or mortar according to claim 8, wherein the concrete process of verifying the treatment protective measures in the step eight is as follows:
respectively taking 18 core samples or strip-shaped test blocks from the core samples or test blocks retrieved on site, respectively putting the core samples or strip-shaped test blocks into test block boxes, respectively putting the test blocks into six environments which are naturally dry and isolated from air, naturally dry and contacted with air, moist in appearance and isolated from air, moist in appearance and contacted with air, saturated and isolated from air, saturated in water and contacted with air for testing, wherein 3 test blocks are in each environment, then putting the test block boxes into a water bath, raising the temperature from the room temperature to 100 +/-2 ℃, after constant boiling for 6h, naturally cooling to the room temperature, checking and recording the damage condition of the test blocks in each environment, and judging which environment is most beneficial and most harmful to the test blocks in an intact state according to the damage condition of the test blocks, thereby giving a treatment protection suggestion.
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| CN117309661A (en) * | 2023-11-28 | 2023-12-29 | 睢宁县泰宁建材有限公司 | Concrete quality on-line measuring system |
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| CN117309661A (en) * | 2023-11-28 | 2023-12-29 | 睢宁县泰宁建材有限公司 | Concrete quality on-line measuring system |
| CN117309661B (en) * | 2023-11-28 | 2024-02-23 | 睢宁县泰宁建材有限公司 | Concrete quality on-line measuring system |
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