CN104297458B - A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method - Google Patents
A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method Download PDFInfo
- Publication number
- CN104297458B CN104297458B CN201410594818.0A CN201410594818A CN104297458B CN 104297458 B CN104297458 B CN 104297458B CN 201410594818 A CN201410594818 A CN 201410594818A CN 104297458 B CN104297458 B CN 104297458B
- Authority
- CN
- China
- Prior art keywords
- carbon fiber
- fiber reinforced
- reinforced concrete
- resistivity
- measuring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Abstract
A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method provided by the invention, comprises the step such as measurement, the measurement of carbon fiber reinforced concrete damage-resistivity incidence relation of the making of carbon fiber reinforced concrete standard specimen, mark measurement point, ultrasonic velocity and resistance.The method uses conventional measuring equipment, simple to operation, can measure the damage-resistivity incidence relation of carbon fiber reinforced concrete material in different loads situation, measurement result is more accurate, for concrete Non-Destructive Testing is laid a good foundation, there is practical engineering application and theory value widely.
Description
Technical field
The present invention relates to a kind of concrete material damage-resistivity incidence relation measuring method under load effect, particularly a kind of carbon fiber reinforced concrete material damage-resistivity incidence relation measuring method under static load effect.
Background technology
With the filled with carbon fibers concrete of low dose, the permanance of concrete material, tensile strength and anti-bending strength can be improved.Carbon fiber reinforced concrete is a kind of multi-functional, intelligentized excellent material, has application prospect widely.In metal protection, this material can be used as cathodic protection material; In building structure, this material can be used to heating or building safety monitoring; On some special roads and airfield runway, this material can be used to melting ice and snow; In military blindage and some communications services, this material can be used for electromagnetic screen etc.In these facilities process under arms, inevitably damage the impairment of the constitution, so be necessary to monitor the damage of these facilities, occur to avoid disaster.But, also do not have document to disclose at present and relate to carbon fiber reinforced concrete material damage-resistivity incidence relation measuring method under static load effect.
Summary of the invention
Goal of the invention: in order to overcome above-mentioned the deficiencies in the prior art, the object of the present invention is to provide a kind of carbon fiber reinforced concrete being subject to damage-resistivity incidence relation measuring method in static load situation.
Technical scheme: a kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method provided by the invention, comprises the following steps:
(1) making of carbon fiber reinforced concrete standard specimen: the mix-design according to carbon fiber reinforced concrete makes carbon fiber reinforced concrete standard specimen; Meanwhile, the parallel insertion of difference two pieces of pre-buried electrode materials on any two-phase opposite; Carry out standard curing to carbon fiber reinforced concrete standard specimen, condition is curing temperature 20 ± 2 DEG C, humidity more than 95%, and curing time is 28 days;
(2) measurement point is marked: two opposite planar that selection carbon fiber reinforced concrete standard specimen parallels with the electrode material of insertion are as measuring surface, the diagonal line of a measuring surface is wherein selected arbitrarily three measuring points be designated as measuring point 1,2,3, on relative measurement face with measuring point 1,2,3 corresponding positions select three measuring points to be designated as measuring point 1 ', 2 ', 3 ';
(3) measurement of ultrasonic velocity and resistance: uniform painting spreads couplant on the transducer of nonmetal ultrasonic detector, and by the transmitting terminal of transducer along being fixed on measuring point 1 with measuring surface vertical direction, by the receiving end of transducer along being fixed on measuring point 1 ' with relative measurement face vertical direction, record the ultrasonic velocity of measuring point 1; Adopting uses the same method measures the ultrasonic velocity of measuring point 2 and 3 successively; Two of resistance measuring instrument probes are separately fixed on the pre-buried electrode material of carbon fiber reinforced concrete standard specimen, while to carbon fiber reinforced concrete ultrasonic measurement, the resistance of test carbon fiber reinforced concrete test specimen; Be specially: suffered by carbon fiber reinforced concrete standard specimen, load is p respectively
0(p
0=0), p
1p
ntime, ultrasound examination is carried out to each measuring point of carbon fiber reinforced concrete standard specimen, and under recording respective loads, the ultrasonic velocity at measuring point 1,2,3 place of concrete standard part is respectively C
01, C
02, C
03, C
11, C
12, C
13c
n1, C
n2, C
n3, the mean value calculating the ultrasonic velocity of concrete standard part under respective loads is respectively C
0, C
1c
n; Measure the resistance R of carbon fiber reinforced concrete standard component simultaneously
0, R
1r
n; Wherein, P
n≤ σ S, σ are carbon fiber reinforced concrete material mix proportion design strength, and S is concrete standard part loading end area, and the two is known numeric value; N=0,1,2;
(4) carbon fiber reinforced concrete damage-resistivity incidence relation is measured: by the mean value C of the ultrasonic velocity of carbon fiber reinforced concrete standard component under the different loads effect that obtains
0, C
1c
n, be updated to concrete damage expression formula
in (k=0,1,2n), wherein, D is carbon fiber reinforced concrete impairment value; By the resistance R of carbon fiber reinforced concrete standard component under the different loads effect that obtains
0, R
1r
n, be updated to resistivity expression formula
wherein, k=0,1,2n, L are the distance between carbon fiber reinforced concrete two electrode; With resistivity value α
1, α
2α
nfor horizontal ordinate, with impairment value D corresponding under corresponding stress state
0, D
1d
nfor ordinate, obtain the cubic B-spline smooth curve of D=f (α) function, be the carbon fiber reinforced concrete test specimen damage under load effect-resistivity incidence relation.
Wherein, in step (1), carbon fiber reinforced concrete standard specimen is of a size of 150mm × 150mm × 150mm; Pre-buried electrode material is of a size of 150mm × 175mm, and the nearest parallel plan range of the pre-buried electrode material of every block is 25mm, and the spacing of two pieces of pre-buried electrode materials is 100mm; The material of pre-buried electrode material is stainless (steel) wire or stainless steel substrates or carbon cloth.
Above-mentioned carbon fiber reinforced concrete material damage expression formula obtains through following derivation based on " theory of stress wave ", " damage mechanics " material, the following describes the derivation of carbon fiber reinforced concrete material damage expression formula:
Ultrasound wave passes through three kinds of forms at carbon fiber reinforced concrete Propagation, i.e. compressional wave, shear wave and surface wave.And vertical velocity of wave propagation is the fastest, therefore the present invention mainly studies the propagation law of the compressional wave in carbon fiber reinforced concrete.
Assuming that carbon fiber reinforced concrete is uniform dielectric, so its dynamic elastic modulus E
dwith the longitudinal wave velocity C propagated wherein
1relation can represent with following formula:
In above formula: E
dfor the dynamic modulus of elasticity of carbon fiber reinforced concrete, C
1for the longitudinal wave velocity propagated in carbon fiber reinforced concrete, ρ is the density of carbon fiber reinforced concrete, and v is the Poisson ratio of carbon fiber reinforced concrete material.
So obtain the initial velocity of wave E at carbon fiber reinforced concrete material
0,
In above formula: C
0for the initial longitudinal wave velocity propagated in carbon fiber reinforced concrete, ρ
0for the initial density of carbon fiber reinforced concrete, v
0for the initial Poisson ratio of carbon fiber reinforced concrete material.
Carbon fiber reinforced concrete is in pressurized process, the density of this research supposition carbon fiber reinforced concrete is constant, and the impact that effects of Poisson's ratio damages carbon fiber reinforced concrete is little, so the damage development of carbon fiber reinforced concrete in pressurized process just shows as the evolution of its dynamic modulus of elasticity, if in carbon fiber reinforced concrete pressurized process, the damage caused carbon fiber reinforced concrete is D, then we can draw following formula
(2) formula is substituted into (3) formula, just can draw the expression formula of the damage D of carbon fiber reinforced concrete, as follows:
In above formula: C
0for the initial longitudinal wave velocity propagated in carbon fiber reinforced concrete, C be carbon fiber reinforced concrete in different loads situation, the ultrasound wave longitudinal wave velocity propagated wherein.
Beneficial effect: carbon fiber reinforced concrete damage-resistivity incidence relation measuring method provided by the invention uses conventional measuring equipment, simple to operation, damage-resistivity the incidence relation of carbon fiber reinforced concrete material in different loads situation can be measured, measurement result is more accurate, for concrete Non-Destructive Testing is laid a good foundation, there is practical engineering application and theory value widely.
The invention discloses a kind of carbon fiber reinforced concrete material damage-resistivity incidence relation measuring method under static load effect, each measuring point ultrasonic velocity is measured successively with supersonic reflectoscope, then its mean value is asked, simultaneously with the resistance of carbon fiber reinforced concrete material in resistance measuring instrument measurement different loads situation.The former can draw the impairment value of carbon fiber reinforced concrete material, and the latter can obtain its resistivity value.Carry out B-spline Curve matching according to each measurement data, easily can be realized by MATLAB mathematical software; The carbon fiber reinforced concrete damage expression formula derived in theory, drawn by theory of stress wave and damage Mechanical Analysis, form is succinct, and method is reliable.
The instrument and equipment that the inventive method uses is simple, and key instrument equipment is quiet supersonic reflectoscope and resistance measuring instrument, and the two is common instrument and equipment in engineering scientific research; Data acquisition and procession method is simple, each measuring point ultrasonic velocity can be measured successively with supersonic reflectoscope, then its mean value is asked, measure carbon fiber reinforced concrete test specimen resistance with resistance measuring instrument simultaneously, carry out B-spline Curve matching according to each measurement data, easily can be realized by MATLAB mathematical software; The concrete damage expression formula derived in theory, is drawn by theory of stress wave and damage Mechanical Analysis, and form is succinct, and method is reliable.
Accompanying drawing explanation
Fig. 1 is ultrasound wave measuring point distribution schematic diagram on carbon fiber reinforced concrete standard specimen;
Fig. 2 is the distribution schematic diagram of ultrasound wave measuring point, electrode material on carbon fiber reinforced concrete standard specimen;
Fig. 3 is the carbon fiber reinforced concrete material damage under the load effect-resistivity incidence relation in embodiment.
Embodiment
Below in conjunction with accompanying drawing the present invention made and further illustrating.
Carbon fiber reinforced concrete material is damage-resistivity incidence relation measuring method under static load effect, comprises following concrete steps:
1) making of carbon fiber reinforced concrete standard specimen: according to the mix-design of carbon fiber reinforced concrete, carry out the making of this kind of concrete standard test specimen, standard specimen is of a size of 150mm × 150mm × 150mm, while production standard test specimen, at distance one of them 25mm place, relative both sides of test specimen, insert two cube electrode materials 4 in opposite directions, require that electrode material is of a size of 150mm × 175mm, the spacing of electrode material 4 in carbon fiber reinforced concrete test specimen is 100mm, the material of electrode material 4 is 304 stainless (steel) wires, also can select stainless steel substrates or carbon cloth; Then carry out standard curing to the concrete sample that completes, standard curing condition is: curing temperature 20 ± 2 DEG C, humidity more than 95%;
2) measurement point is marked: two opposite planar that selection carbon fiber reinforced concrete standard specimen parallels with the electrode material of insertion are as measuring surface, the diagonal line of a measuring surface is wherein selected arbitrarily three measuring points be designated as measuring point 1,2,3, on relative measurement face with measuring point 1,2,3 corresponding positions select three measuring points to be designated as measuring point 1 ', 2 ', 3 '; See Fig. 1;
3) take out nonmetal ultrasonic detector, and transducer and main frame are connected firmly, stablize.According to the size etc. of concrete standard part, the parameter of nonmetal ultrasonic detector is set.It is as shown in table 1 below that this measures super ripple detector optimum configurations;
The parameter of table 1 nonmetal ultrasonic detector
| Emitting voltage | 1000V | Test dominant frequency | Test |
| Sampling period | 0.4ms | Transmitted wave is wide | 0.08ms |
4) measurement of ultrasonic velocity and resistance: uniform painting spreads couplant on the transducer of nonmetal ultrasonic detector, and by the transmitting terminal of transducer along being fixed on measuring point 1 with measuring surface vertical direction, by the receiving end of transducer along being fixed on measuring point 1 ' with relative measurement face vertical direction, record the ultrasonic velocity of measuring point 1; Adopting uses the same method measures the ultrasonic velocity of measuring point 2 and 3 successively; Two of resistance measuring instrument probes are separately fixed on the pre-buried electrode material of carbon fiber reinforced concrete standard specimen, while to carbon fiber reinforced concrete ultrasonic measurement, the resistance of test carbon fiber reinforced concrete test specimen; The initial resistance of the present embodiment carbon fiber reinforced concrete test specimen is 7.5k about Ω, and selecting resistance measuring instrument measures gear is 10
3shelves.Concrete measuring process is as follows:
Suffered by concrete standard part, load is 0kN, 100kN, 200kN, 300kN, 400kN, 500kN, 600kN (carbon fiber reinforced concrete material mix proportion design strength 30MPa, concrete standard part loading end area 0.0225 ㎡) time, respectively ultrasound examination is carried out to each measuring point of concrete standard part, and the measuring point 1 of concrete standard part under recording respective loads, 2, the ultrasonic velocity at 3 places is respectively 4.624km/s, 4.639km/s, 4.652km/s, 4.416km/s, 4.447km/s, 4.433km/s, 4.122km/s, 4.198km/s, 4.164km/s, 3.746km/s, 3.761km/s, 3.785km/s, 3.248km/s, 3.268km/s, 3.275km/s, 2.657km/s, 2.690km/s, 2.635km/s, 1.935km/s, 1.949km/s, 1.925km/s.The mean value obtaining the ultrasonic velocity of concrete standard part under respective loads is respectively 4.638km/s, 4.432km/s, 4.161km/s, 3.764km/s, 3.264km/s, 2.661km/s, 1.936km/s.The resistance simultaneously measuring carbon fiber reinforced concrete standard component is respectively 7.74k Ω, 8.65k Ω, 9.23k Ω, 9.47k Ω, 9.85k Ω, 10.68k Ω, 11.97k Ω.
5) by mean value 4.638km/s, 4.432km/s, 4.161km/s, 3.764km/s, 3.264km/s, 2.661km/s, 1.936km/s of the ultrasonic velocity of concrete standard part under the different loads effect that obtains, concrete damage expression formula is updated to
in (k=0,1,2n), impairment value 0.0000,0.0869,0.1951,0.3414,0.5047,0.6708,0.8258 corresponding under obtaining corresponding stress state.By resistance 7.74k Ω, the 8.65k Ω of carbon fiber reinforced concrete standard component under the different loads effect that obtains, 9.23k Ω, 9.47k Ω, 9.85k Ω, 10.68k Ω, 11.97k Ω, be updated to resistivity expression formula
(k=0,1,2n, L are distance between carbon fiber reinforced concrete two electrode and 100mm) in, resistivity value 1741.50 Ω m, 1946.25 Ω m, 2076.75 Ω m, 2130.75 Ω m, 2216.25 Ω m, 2403.00 Ω m, 2693.25 Ω m corresponding under obtaining corresponding stress state.With the resistivity value obtained under different stress for horizontal ordinate, with impairment value corresponding under corresponding stress state for ordinate, data fitting is carried out with MATLAB mathematical software, obtain the cubic B-spline smooth curve of D=f (α) function, just can obtain the carbon fiber reinforced concrete material damage under load effect-resistivity incidence relation, see Fig. 2.
Claims (2)
1. a carbon fiber reinforced concrete damage-resistivity incidence relation measuring method, is characterized in that: comprise the following steps:
(1) making of carbon fiber reinforced concrete standard specimen: the mix-design according to carbon fiber reinforced concrete makes carbon fiber reinforced concrete standard specimen; Meanwhile, the parallel insertion of difference two pieces of pre-buried electrode materials on any two-phase opposite; Carry out standard curing to carbon fiber reinforced concrete standard specimen, condition is curing temperature 20 ± 2 DEG C, humidity more than 95%, and curing time is 28 days;
(2) measurement point is marked: two opposite planar that selection carbon fiber reinforced concrete standard specimen parallels with the electrode material of insertion are as measuring surface, the diagonal line of a measuring surface is wherein selected arbitrarily three measuring points be designated as measuring point 1,2,3, on relative measurement face with measuring point 1,2,3 corresponding positions select three measuring points to be designated as measuring point 1 ', 2 ', 3 ';
(3) measurement of ultrasonic velocity and resistance: uniform painting spreads couplant on the transducer of nonmetal ultrasonic detector, and by the transmitting terminal of transducer along being fixed on measuring point 1 with measuring surface vertical direction, by the receiving end of transducer along being fixed on measuring point 1 ' with relative measurement face vertical direction, record the ultrasonic velocity of measuring point 1; Adopting uses the same method measures the ultrasonic velocity of measuring point 2 and 3 successively; Two of resistance measuring instrument probes are separately fixed on the pre-buried electrode material of carbon fiber reinforced concrete standard specimen, while to carbon fiber reinforced concrete ultrasonic measurement, the resistance of test carbon fiber reinforced concrete test specimen; Be specially: suffered by carbon fiber reinforced concrete standard specimen, load is P respectively
0(P
0=0), P
1p
ntime, ultrasound examination is carried out to each measuring point of carbon fiber reinforced concrete standard specimen, and under recording respective loads, the ultrasonic velocity at measuring point 1,2,3 place of concrete standard part is respectively C
01, C
02, C
03, C
11, C
12, C
13c
n1, C
n2, C
n3, the mean value calculating the ultrasonic velocity of concrete standard part under respective loads is respectively C
0, C
1c
n; Measure the resistance R of carbon fiber reinforced concrete standard component simultaneously
0, R
1r
n; Wherein, P
n≤ σ S, σ are carbon fiber reinforced concrete material mix proportion design strength, and S is concrete standard part loading end area, and the two is known numeric value; N=0,1,2;
(4) carbon fiber reinforced concrete damage-resistivity incidence relation is measured: by the mean value C of the ultrasonic velocity of carbon fiber reinforced concrete standard component under the different loads effect that obtains
0, C
1c
n, be updated to concrete damage expression formula
in (k=0,1,2n), wherein, D is carbon fiber reinforced concrete impairment value; By the resistance R of carbon fiber reinforced concrete standard component under the different loads effect that obtains
0, R
1r
n, be updated to resistivity expression formula
wherein, k=0,1,2n, L are the distance between carbon fiber reinforced concrete two electrode; With resistivity value α
1, α
2α
nfor horizontal ordinate, with impairment value D corresponding under corresponding stress state
0, D
1d
nfor ordinate, obtain the cubic B-spline smooth curve of D=f (α) function, be the carbon fiber reinforced concrete test specimen damage under load effect-resistivity incidence relation.
2. a kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method according to claim 1, is characterized in that: in step (1), carbon fiber reinforced concrete standard specimen is of a size of 150mm × 150mm × 150mm; Pre-buried electrode material is of a size of 150mm × 175mm, and the nearest parallel plan range of the pre-buried electrode material of every block is 25mm, and the spacing of two pieces of pre-buried electrode materials is 100mm; The material of pre-buried electrode material is stainless (steel) wire or stainless steel substrates or carbon cloth.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410594818.0A CN104297458B (en) | 2014-10-29 | 2014-10-29 | A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410594818.0A CN104297458B (en) | 2014-10-29 | 2014-10-29 | A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104297458A CN104297458A (en) | 2015-01-21 |
| CN104297458B true CN104297458B (en) | 2015-11-18 |
Family
ID=52317279
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410594818.0A Active CN104297458B (en) | 2014-10-29 | 2014-10-29 | A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104297458B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106404850B (en) * | 2016-11-08 | 2023-07-25 | 南京航空航天大学 | Method for testing anisotropic conductivity and interlayer contact resistivity of carbon fiber composite material |
| CN107525852A (en) * | 2017-10-11 | 2017-12-29 | 东南大学 | A kind of concrete carbonization depth method of testing based on ultrasonic method |
| CN107894462A (en) * | 2017-11-09 | 2018-04-10 | 东南大学 | A kind of method of testing of concrete parts carbonizing zone depth |
| CN109002989A (en) * | 2018-07-20 | 2018-12-14 | 广东工业大学 | A kind of concrete structure repairs detection method, system equipment and storage medium |
| CN110501386B (en) * | 2019-07-17 | 2020-08-25 | 武汉大学 | Rock burst early warning method based on carbon fiber concrete |
| CN110779960B (en) * | 2019-11-13 | 2021-07-30 | 上海交通大学 | CFRP damage detection method based on resistance change |
| CN111006993A (en) * | 2019-11-22 | 2020-04-14 | 太原理工大学 | Stability detection device for gangue cemented filling material and use method thereof |
| CN112160240A (en) * | 2020-10-23 | 2021-01-01 | 同济大学 | Stress damage self-induction concrete bridge deck and manufacturing method |
| CN113603428A (en) * | 2021-08-31 | 2021-11-05 | 中铁二院重庆勘察设计研究院有限责任公司 | Ultrahigh-performance concrete material with conductivity and sensitivity, preparation method thereof and sensitivity detection method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5262967A (en) * | 1991-07-15 | 1993-11-16 | Braun Intertec Engineering, Inc. | System for testing and inspecting concrete |
| CN1987458A (en) * | 2006-11-15 | 2007-06-27 | 翁兴中 | Method for detecting anti-cracking performance of airport cement concrete road surface |
| CN101140265A (en) * | 2007-10-17 | 2008-03-12 | 南京大学 | Method for bias measuring water content of measuring and cracks using non-linearity syntony frequency |
-
2014
- 2014-10-29 CN CN201410594818.0A patent/CN104297458B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5262967A (en) * | 1991-07-15 | 1993-11-16 | Braun Intertec Engineering, Inc. | System for testing and inspecting concrete |
| CN1987458A (en) * | 2006-11-15 | 2007-06-27 | 翁兴中 | Method for detecting anti-cracking performance of airport cement concrete road surface |
| CN101140265A (en) * | 2007-10-17 | 2008-03-12 | 南京大学 | Method for bias measuring water content of measuring and cracks using non-linearity syntony frequency |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104297458A (en) | 2015-01-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104297458B (en) | A kind of carbon fiber reinforced concrete damage-resistivity incidence relation measuring method | |
| Agioutantis et al. | Potential of acoustic emissions from three point bending tests as rock failure precursors | |
| Wu et al. | An experimental study of dynamic tensile failure of rocks subjected to hydrostatic confinement | |
| Chau et al. | Uniaxial compressive strength and point load strength of rocks | |
| Kahraman | A correlation between P-wave velocity, number of joints and Schmidt hammer rebound number | |
| Lataste et al. | Characterisation of fibres distribution in a steel fibre reinforced concrete with electrical resistivity measurements | |
| Wiwattanachang et al. | Monitoring crack development in fiber concrete beam by using electrical resistivity imaging | |
| CA2486366A1 (en) | Method and equipment for inspecting reinforced concrete pipe | |
| Miranda et al. | Sonic Impact Method–A new technique for characterization of stone masonry walls | |
| CN111521691B (en) | Composite material Lamb wave damage imaging method based on time reversal weighted distribution | |
| CN102928512A (en) | Test method of rock aging deterioration process | |
| CN108802500A (en) | A kind of computational methods and system of high-precision non-destructive testing material relative dielectric constant | |
| CN102865952A (en) | Nondestructive testing method for working stress of concrete | |
| CN104048914B (en) | A kind of monitor metal device of corrosion in different cement accidents | |
| CN110879278A (en) | Qualitative and quantitative detection method for defects of thin-wall centrifugal concrete steel pipe tower | |
| CN110646282A (en) | Surrounding rock elastic reaction coefficient k determination method based on surrounding rock quality index BQ | |
| CN104165795B (en) | A kind of residue anti-bending bearing capacity assay method of ancient building wooden frame | |
| Lei et al. | Strain localization and cracking behavior of sandstone with two gypsum-infilled parallel flaws | |
| Zhou et al. | Localization of cracks in cementitious materials under uniaxial tension with electrical resistance tomography | |
| Li et al. | Shear test on damage evolution of brick masonry based on acoustic emission technique | |
| Zhao et al. | Fractal characteristics and acoustic emission b-value of cement superfine tailings backfill with initial defect consideration | |
| Lopes et al. | Concrete compressive strength estimation by means of nondestructive testing: a case study | |
| CN1296697C (en) | Determining method for mechanics quality stable threshold of rock structural face | |
| CN104198587A (en) | Method for measuring damage evolution of concrete material under action of static load | |
| CN115585922A (en) | Drilling type multi-point and multi-direction coal rock mass stress meter and coal rock mass stress monitoring method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |