CN102116716A - Method for determining modulus of elasticity of plastic concrete - Google Patents
Method for determining modulus of elasticity of plastic concrete Download PDFInfo
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- CN102116716A CN102116716A CN2010102497237A CN201010249723A CN102116716A CN 102116716 A CN102116716 A CN 102116716A CN 2010102497237 A CN2010102497237 A CN 2010102497237A CN 201010249723 A CN201010249723 A CN 201010249723A CN 102116716 A CN102116716 A CN 102116716A
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Abstract
The invention discloses a method for determining modulus of elasticity of plastic concrete. 3 150x150x300mm prism testing pieces are manufactured under industrial standards, the testing pieces to be measured are placed on a testing machine and starting reading is recorded, the testing machine is started, deformation values under various loads are recorded, and static compressive modulus of elasticity of the testing pieces are calculated in accordance with the following equation Ec = (P1/A) x (L/deltaL), wherein L is the full length of the testing pieces. The average value of the static compressive modulus of elasticity of the three testing pieces is regarded as the testing result. The method fills in the blank in the aspect of plastic concrete testing method, is characterized by adopting full gauge length for measuring the testing pieces, avoiding pre-pressing procedure and taking the slope of 40% secant as the elastic modulus value of the plastic concrete, and simultaneously eliminates 0.5MPa of stress and the calculation of stress items thereof from the calculation of the testing result, thereby overcoming the defect of large error in the prior method, achieving simpler and faster testing process and being advantageous for the popularization of the method.
Description
Technical field
The invention belongs to the water conservancy and hydropower technical field of construction, be specifically related to a kind of in impervious wall construction in order to measure the test method of plastic concrete elastic modulus
Background technology
Plastic concrete is meant that the compressive strength scope is that 1～5MPa, elastic modulus are that 300～2000MPa, infiltration coefficient are n * 10
-6～n * 10
-8, and have the underwater concrete of large fluidity, be used in the cut-pff wall structure of earth and rockfill dam more.Because the cement consumption that uses in the match ratio is less, be mixed with more bentonitic clay and clay, and be mixed with water reducer and air entraining agent improves its impervious ability, therefore, plastic concrete belong to have low-intensity, a class special concrete of certain impervious ability, low elastic modulus and big strain characteristics.(compressive strength is that 15～35MPa, elastic modulus are that 22000～31500MPa, infiltration coefficient are≤4.19 * 10 with common underwater concrete
-9) compare, the compressive strength of plastic concrete is about 1/10th, and the requirement of elastic modulus and infiltration coefficient then differs nearly a hundred times.Because these performances that plastic concrete has, the characteristics that are more or less the same of elastic modulus and dam body particularly, it is poor with the depression difference and the displacement of soil layer on every side to reduce the cut-pff wall top under effects such as sedimentation, thereby reduce or avoid the immense pressure that the cut-pff wall top is subjected to and the possibility that occurs destroying helps the cut-pff wall security.Simultaneously, plastic concrete also has the simple and economical characteristics fast of construction technology, so not only increasing at earth and rockfill dam and seepage prevention of cofferdam application in engineering in recent years, dangerously weak reseroirs are reinforced or the first-selection of treatment technology scheme but also become.
But, along with the practice of design of a large amount of plastic concrete match ratio and construction inspection by sampling, all in various degree reflect the problem that plastic concrete exists design objective not to be complementary.That is: when the compressive strength of plastic concrete meets design requirement, but elastic modulus is much higher than design objective.This evaluation work to cut-pff wall plastic concrete construction quality has caused certain difficulty, and this mainly is because existing elasticity modulus test method existing problems.
At present, the test of plastic concrete elastic modulus is carried out according to the concrete for hydraulic structure test method.This method is primarily aimed at the normal concrete of approximate rigidity, yet for plastic concrete, obviously exists unreasonable place.For example in the test method of existing elastic modulus, requirement is carried out three times or above precompressed concrete sample, and then carry out formal test, its objective is and eliminate irreclaimable residual deformation in the concrete, this measure is necessary to normal concrete, but just may not be suitable to the bigger plastic concrete of distortion; Secondly, in the computing formula of elastic modulus, the stress value of regulation dividend adopts the stress of 0.4 failing load to deduct the poor of stress 0.5MPa, and the strain value of divisor also to be the strain of 0.4 failing load deduct the poor of stress 0.5MPa strain.The stress that might occur 0.4 failing load when the intensity of plastic concrete is hanged down does not also reach the situation of 0.5MPa.Therefore, a kind of elasticity modulus test method that more meets the plastic concrete characteristic of research is imperative.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art, a kind of test method of measuring the plastic concrete elastic modulus is provided,, fill up the blank of plastic concrete elasticity modulus test method so that estimate the deformation performance of plastic concrete more exactly.
Purpose of the present invention is achieved by the following technical programs.
A kind of test method of measuring the plastic concrete elastic modulus may further comprise the steps:
1, makes 3 test specimens by ' moulding of concrete sample and maintenance process ' industry standard;
2, arrive test during the length of time, test specimen is taken out from fog room, clean the surface and keep the test specimen humidity;
3, earlier the magnetic force dial framework is installed on the column of testing machine, then clock gauge or displacement transducer is fixed on the magnetic force dial framework; Test specimen to be measured is placed on the lower platen of testing machine, the center of test specimen should with testing machine lower platen centrally aligned; Start testing machine, adjust the testing machine ball seat, top board is contacted evenly with the test specimen surface; Keeping pressing plate to contact but load reads the initial reading of clock gauge or displacement transducer when being 0 state with test specimen;
4, start testing machine, test, write down the deformation values under the loads at different levels, when the loading load reaches 50% failing load, unload clock gauge or displacement transducer, be depressed into test specimen with identical speed and destroy with the loading speed of 0.2～0.3MPa/s;
5, be calculated as follows the static(al) pressure-proof elasticity modulus of test specimen, be accurate to 1MPa:
Ec＝(P
1/A)×(L/ΔL)
In the formula: Ec---static(al) pressure-proof elasticity modulus, MPa
P
1---40% failing load, N
L---measure the gauge length of distortion, i.e. the total length of test specimen, mm
The deformation values of Δ L---stress from 0 to 40% failing load, mm
A---test specimen bearing area, mm
2
6, with the mean value of the static(al) pressure-proof elasticity modulus measured value of three test specimens as test findings.
Wherein, deformation values 〉=6 under the described load at different levels.
The prism of preferred 150 * 150 * 300mm of specification of test specimen.
When adopting φ 150 * 300mm test specimen to test, it is the elastic modulus of standard specimen 150 * 150 * 300mm that test findings should multiply by 1.2 coefficient conversion.
With respect to prior art, the present invention has the following advantages:
1, the present invention has filled up the blank of plastic concrete test method, the method that adopts full gauge length to measure test piece deformation is carried out the elasticity modulus test of plastic concrete, can avoid can destroying the defective that the lower inner structure of plastic concrete intensity causes bigger test error because of fixation measuring distortion support in the existing method.The elastic mould value that test findings of the inventive method and triaxial test obtain is comparatively approaching, and meets " the scope that water power water conservancy rules concrete cut job specifications DL/T5199-2004 requires.
2, cancel the characteristics that the precompressed program of test specimen also met plastic concrete, the elastic modulus that obtains can reflect the deformation performance of plastic concrete comparatively really.
On behalf of the elastic mould value of plastic concrete, the calculating of while test findings, slope that 3, adopt full gauge length to measure the distortion of test specimen, cancellation precompressed program, to get 40% secant rejected the stress of 0.5MPa and the calculating of dependent variable thereof.These improvement all make the present invention compare with the test method of applying mechanically, and its process of the test is simple and fast more, help popularizing and promoting of new test method.
Description of drawings
Fig. 1 is nonstandard 300 stress-strain diagrams (K19) figure in the embodiment of the invention 1.
Fig. 2 is nonstandard in the embodiment of the invention 1 (circle) 300 stress-strain diagrams (K19).
Fig. 3 is nonstandard in the embodiment of the invention 1 (circle) 300 stress-strain diagrams (K31).
Fig. 4 answers triaxial test stress-strain diagram σ for triaxial test in the embodiment of the invention 1
3=0 (K31).
Fig. 5 answers triaxial test stress-strain diagram σ for triaxial test in the embodiment of the invention 1
3=0.1MPa (K31).
Fig. 6 answers triaxial test stress-strain diagram σ for triaxial test in the embodiment of the invention 1
3=0.4MPa (K31).
Fig. 7 answers triaxial test stress-strain diagram σ for triaxial test in the embodiment of the invention 1
3=0.7MPa (K31).
Embodiment
Below by embodiment the present invention is described in further detail, but they are not limitation of the invention.Any conversion based on training centre of the present invention is done all falls into protection scope of the present invention.
Measure the test method of plastic concrete elastic modulus.
1.1 standard/rules that experimental study is used
" general purpose portland cement " GB175-2007
" concrete admixture " GB8076-2008
" concrete for hydraulic structure testing regulations " DL/T5150-2001
" concrete for hydraulic structure sandstone aggregate testing regulations " DL/T5151-2001
" water power water conservancy rules concrete cut job specifications " DL/T5199-2004
" earthwork test rule " SL237-1999
1.2 test material
1.2.1 cement
Be normal silicate 42.5 cement that Huaxin Cement Factory produces, its technical feature is as follows:
The new normal silicate 42.5 cement technology performances of table 1 China
1.2.2 clay and bentonitic clay
Clay is the red clay of Ning Erxian locality, Yunnan Province, adopts and shines dry doubling by the 2mm sieve, and bentonitic clay is the calcium-base bentonite that Yuxi Da Ying street, Yunnan Province produces.Clay and bentonitic clay all adopt dried method of mixing to carry out concrete mixing and stirring, and its physical property test achievement sees Table 2:
Table 2 clay and bentonitic physical property test achievement
| Kind | Water percentage/% | Proportion | Liquid limit/% | Plastic limit/% | Plasticity index | ＜0.005mm/％ | ＜0.002mm/％ |
| Clay | 3.03 | 2.67 | 75 | 38 | 37 | 70 | 56 |
| Bentonitic clay | 0.67 | 2.68 | 45 | 22.5 | 22.5 | 71 | 50 |
1.2.3 sandstone material
Be pierite artificial sand and rubble (being divided into stone among 5～20mm gravelstone and the 20～40mm) that cattle pen sky over the river card power station, Zhaotong sandstone system produces, the physical property test achievement of artificial sand and rubble sees Table 3, table 4:
Table 3 artificial sand physical property test achievement
Table 4 rubble physical property test achievement
1.2.4 additive
The FDN-MTG efficient retarding and water reducing agent that additive adopts Yunnan Ni Kang building materials company limited to produce, recommending volume is 0.6～1.2% of gel material content, the volume of test is 1%; Use the NK air entraining agent of the said firm, recommending volume is 0.005～0.015% of gel material content, and test mixes 0.01%.The technical feature check achievement of water reducer and air entraining agent sees Table 5:
Table 5 water reducer and air entraining agent technical feature check achievement
1.2.5 mixing water
The concrete mixing water running water of making a living.
2, the technical route of elasticity modulus test method of research plastic concrete is: select for use six kinds of test methods that elastic modulus is compared test---filters out the test method that the elastic modulus compliant requires and carries out revision test---the final test method of definite plastic concrete elastic modulus that standard specimen and non-standard test specimen compare test by the optional test method---carrying out revision test once more according to the optional test method step---.Experimental study is divided into three phases to be carried out, and the research purpose in each stage is as follows:
Phase one mainly solves the design of plastic concrete match ratio, utilizes various test methods that elastic modulus is compared test simultaneously, and test findings is analyzed comparison, selects satisfied relatively test method and carries out primary study for subordinate phase;
Subordinate phase adopts selected elasticity modulus test method to carry out revision test, intends passing through the reliability of the repeatability of achievement with the qualification test method.The match ratio of test also increased a part of secondary and has joined concrete mix except that the employing repetition phase one.Simultaneously,, also increased off-gauge φ 150 * 300mm test specimen and standard specimen and compared,, tentatively determined the plastic concrete elastic modulus by achievement analysis to the different size test specimen for increasing the research dynamics of elasticity modulus test method.
Phase III is according to each step of the elasticity modulus test method of having determined, adopt standard specimen and non-standard test specimen to carry out the test of plastic concrete elastic modulus simultaneously, and compare test with triaxial test, by achievement analysis to replica test and triaxial test, final test method of determining to recommend the plastic concrete elastic modulus.
3, the experimental study of phase one
3.1 the test method of phase one elastic modulus
In the phase one to the Test Research of plastic concrete elastic modulus, adopt six kinds of test methods to carry out altogether, except that the mould of moving, test specimen all adopts the standard specimen of 150 * 150 * 300mm, loading facilities adopts the 1000kN universal testing machine, and the calculating value brief introduction of six kinds of test methods and elastic modulus is as follows:
1. ' mark bullet '---test the elastic modulus that obtains plastic concrete according to the standard method of testing regulations and be called for short ' mark bullet '.Adopt ' TM-2 type modulus of elasticity of concrete analyzer ' to measure the distortion of test specimen in the test, the gauge length of measurement is 150mm, gathers deformation data with ' JX-II type ultimate elongation instrument ', and concrete sample has carried out three precompressed according to standard method.For the stress of the avoiding 40% failing load situation less than 0.5MPa occurs, the calculating of elastic modulus directly adopts the stress of failing load 40% divided by corresponding strain;
2. ' nonstandard 150 bullets '---adopt and measure gauge length 150mm, test specimen does not carry out precompressed, by " stress-strain " curve calculation elastic modulus, and with 10%, 20%, the mean value of the ratio of nine grades of stress and strains of 30%......90% represents, be called for short by ' nonstandard 150 bullets '.Adopt ' TM-2 type modulus of elasticity of concrete analyzer ' to measure the distortion of test specimen, gauge length is 150mm, gathers deformation data with ' JX-II type ultimate elongation instrument '.Compare with ' mark bullet ' by ' nonstandard 150 bullets ', can analyze the influence degree of the precompressed of test specimen elastic modulus;
3. ' nonstandard 300 bullets ',---the gauge length that test is adopted is 300mm, and test specimen does not carry out precompressed, by " stress-strain " curve calculation elastic modulus, and with 10%, 20%, the mean value of the ratio of nine grades of stress and strains of 30%......90% represents, be called for short by ' nonstandard 300 bullets '.Because of gauge length is the test specimen total length, thus adopt the magnetic force dial framework on the column of testing machine, to fix the probe of ' JX-II type ultimate elongation instrument ', for gathering deformation data.Compare with ' nonstandard 150 bullets ', change that can the analysis to measure gauge length is to the influence degree of elastic modulus;
4. (φ 25 * 100mm) measures test piece deformation to ' s strain bullet '---pre-buried SDY strainometer when adopting specimen molding, test specimen does not carry out precompressed, by " stress-strain " curve calculation elastic modulus, and with 10%, 20%, the mean value of the ratio of nine grades of stress and strains of 30%......90% represents, be called for short by ' s strain bullet '.' SQ-2A ' digital electric bridge collection is used in the distortion of test specimen;
5. (φ 20 * 100mm) measures test piece deformation to ' d strain bullet '---pre-buried DI-10 type strainometer when adopting specimen molding, test specimen does not carry out precompressed, by " stress-strain " curve calculation elastic modulus, and with 10%, 20%, the mean value of the ratio of nine grades of stress and strains of 30%......90% represents, be called for short by ' d strain bullet '.The distortion of test specimen uses ' CTY-202P ' shaped steel string frequency recorder to gather;
6. adopt the move mould of moving of instrument test of DT-18W concrete, sample dimensions is 100 * 100 * 400mm.
3.2 the testing program of plastic concrete match ratio
Totally ten groups of the Mix Ratio Test of the plastic concrete of phase one all adopt one-level to join concrete (stone maximum particle diameter 20mm), and the compressive strength scope of design is 1～5MPa.In order to obtain more test result with an amount of experiment work amount, and be convenient to analyze, testing program adopts even distribution that every side's consumption of cement, clay and bentonitic clay (general designation Binder Materials) is carried out arrangement design.Three kinds of materials are respectively got 10 horizontal consumptions, and the arranging situation of level sees Table 6, and the plastic concrete proportioning design adopts determines gel material content earlier, determines the method for other parameters such as water consumption and sand coarse aggregate ratio again by concrete workability.
Horizontal table (the kg/m of table 6 Binder Materials
3)
According to uniform Design and uniform designs table
Annotate [2]Middle U
10 *(10
8) the regulation of use table, under the situation of three factors, ten levels, three factors should be arranged in respectively in first, five and six row.Therefore, the even first column selection cement of distribution table, the 6th column selection clay, the 5th column selection bentonitic clay sees Table 7 according to cement, clay and the bentonite consumption of each tested number of uniform Design table pack:
Table 7 is by the gel material content table (kg/m of uniform Design table pack
3)
3.3 test result and analysis
The plastic concrete Mix Ratio Test is according to the pairing cement of each tested number, clay and bentonite consumption, is to carry out under 1% and 0.01% condition at the fixing volume of water reducer and air entraining agent.Simultaneously, in order to guarantee dried concrete uniform mixing of mixing clay, test adopts the 60L forced mixer to mix and stir, and fixedly the dry mixing time be 1min, and then add water and mix and stir 4min.Phase one plastic concrete Mix Ratio Test achievement sees Table 8:
Table 8 phase one plastic concrete Mix Ratio Test achievement
Annotate: test and be 28d the length of time.
From the phase one test result of table 8 as can be seen:
1. the slump of She Ji plastic concrete match ratio and divergence can satisfy the requirement of cut-pff wall concrete workability, and the air content of mix is about 2%, and cube strength is also in the 1～5MPa scope that requires, and axial compressive strength is more lower slightly;
2. in the pilot project of six kinds of elastic modulus, the elastic mould value that obtains according to the standard method test improves along with the increase of compressive strength, and scope is at 2600～12400MPa, the scope of the 300～2000MPa that requires in the DL/T5199-2004 standard;
3. the elastic mould value that meets DL/T5199-2004 code requirement scope, it is the test result that ' nonstandard 300 bullets ' obtain that the full gauge length test of employing is only arranged, its elastic mould value is in 154～1329MPa scope;
4. in addition, adopt ' nonstandard 150 ' and the also scope of 300～2000MPa in the DL/T5199-2004 standard of the elastic modulus that obtains of pre-buried ' SDY strainometer ' and test methods such as ' DI-10 type strainometers ', its reason may be identical with standard method---and the too small measuring error to low-elasticity-modulus value test specimen of gauge length of measuring distortion is bigger.The gauge length of standard method is 150mm, and ' nonstandard 150 ' gauge length is 150mm also, and the measurement range of pre-buried strainometer also only is 100mm;
5. compare with ' mark bullet ' result who obtains according to standard method, ' nonstandard 150 ' elastic modulus is average on the low side about 10%, and analysis is owing to do not carry out due to the precompressed;
6. the test philosophy of ' mould of moving ' is different with the elastic modulus principle of above-mentioned five kinds of methods test, and therefore, it is understandable that measured value has than big-difference.Yet, concerning normal concrete, there is the mould of moving to be slightly larger than saying of quiet bullet mould, the achievement of this contrast test also has analogue, and also present the rule that the mould value of moving increases with the raising of compressive strength, this has identical rule with the test findings of standard method.
4. subordinate phase experimental study
4.1 test method
Compare by the test practice of phase one with to the analysis of test result, decision emphasis in the test method of subordinate phase is studied the test method of ' nonstandard 300 bullets '., carry out the replica test except utilizing standard specimen, the non-standard test specimen that has also increased φ 150 * 300mm especially compares with it for this reason.The computation processing method of the elastic modulus of the φ 150 * 300mm test specimen that increases is identical with 150 * 150 * 300mm standard specimen, and achievement is represented with ' nonstandard circle 300 bullets '.In addition, also proceed elastic modulus contrast test, with further demonstration test accuracy as a result by standard test method.' nonstandard 150 ', ' mould of moving ' and pre-buried ' SDY strainometer ' reaches the experimental study of four kinds of methods such as ' DI-10 type strainometers ' in cancellation simultaneously.
4.2 Mix Ratio Test scheme
Be the repeatability and the contingency of avoiding testing of investigating test findings, in carrying out the subordinate phase experimental study, specially the plastic concrete match ratio that the phase one is used is carried out revision test, and promptly K11 repeats K1, K12 repetition K2......K20 and repeats K10.In addition, also increased clay or bentonitic clay are only arranged, the use two gratings situation of (the stone maximum particle diameter is 40mm) and the content of the test of the concrete mix of compressive strength scope between 5～15MPa, in the hope of in the larger context elastic modulus being carried out more deep experimental study.
4.3 test result
4.3.1 repeat the achievement of phase one test
Repeating the achievement of phase one test lists in the table 9.
Table 9 repeats phase one plastic concrete Mix Ratio Test achievement
Annotate: circular shaft pressure degree is after φ 150 * 300mm test specimen is finished elasticity modulus test, adds to failing load again and calculates and get.
Achievement analysis to revision test:
1. compare with the test result of phase one, the cube strength and the axial compressive strength of subordinate phase revision test are more or less the same, and infiltration coefficient has certain difference, but better regularity is in the phase one;
2. adopt elastic modulus regularity that standard test method obtains significantly better than the phase one, but trial value is still between 2500MPa～10900MPa, thereby proved that once more the elastic modulus that obtains with the standard method test is higher than the scope that plastic concrete requires;
3. the elastic modulus scope of prism test specimen ' nonstandard 300 ' is more or less the same with the phase one at 118MPa～1227MPa, but regularity also has been many.And the elastic modulus of the non-standard test specimen of right cylinder of employing φ 150 * 300mm is (promptly nonstandard
300 circlesBullet) scope is between 104MPa～814MPa, the elastic modulus less than ' nonstandard 300 ', and its mean ratio is about 61%.' stress-strain ' curve of two kinds of size test specimens of test number K19 is seen Fig. 1, Fig. 2.From the stress-strain diagram deformation curve shape basically identical of two kinds of size test specimens as can be seen, be characterized in that the slope at two ends is less end to end, scope has reflected that 0～0.3 and the two ends of＞0.8 failing load plastic concrete this two stage distortion under the load-bearing state is bigger.
4.3.2 increase the achievement of part test content
The match ratio that increases the part test content has: as only having clay or bentonitic clay, use secondary to be equipped with and the concrete mix of compressive strength scope between 5～15MPa, its test result sees Table 10.Wherein K21～K24 is respectively I and II and joins and only mix clay or bentonitic plastic concrete match ratio; K25～K28 is respectively the I and II of compressive strength scope between 5～15MPa and joins and only mix clay or bentonitic match ratio.
Table 10 increases part plastic concrete Mix Ratio Test achievement
Test result from last table is as can be seen:
1. under identical water-cement ratio and clay rate or bentonitic clay rate condition, the cube strength and the axial compressive strength of a grating and two gratings are more or less the same; The infiltration coefficient of one grating is slightly less than secondary and joins concrete; No matter be to adopt standard method, the elastic modulus that still adopts non-standard full gauge length to obtain is two gratings and joins concrete greater than one-level, and rule is identical with normal concrete.
2. compare with the elastic modulus that obtains by standard method, ' nonstandard 300 ' elastic modulus is still less, as both ratio of K21 be that 475/5000=9.5%, K22 are 7.4%, K23 is 6.5%, K24 is 6.7%, K25 is 9.7%, K26 is 7.6%, K27 is 11.5%, K28 is 11.5%, average out to 8.8%; The mean ratio of K11～K20 is that the elastic modulus that 10.4%, two kind of test method obtains differs nearly 10 times.
3. ' nonstandard
300 circlesBullet ' be significantly less than once more ' nonstandard
300Bullet ', both mean ratios are about 62%.Analysis is under the height of the test specimen condition identical with gauge length, and the compression area of cylinder specimen only is 17671mm
2, and the compression area of prism test specimen is 22500mm
2, the ratio of area is 0.785, under identical stress condition, the little distortion of compression area in theory should be greatly, so elastic modulus can be smaller.
4.3.4 test method is to influencing the analysis-by-synthesis of elastic modulus index
Compare with the standard method of carrying out elasticity modulus test according to testing regulations, the elastic modulus (being nonstandard 300 bullets) that adopts full gauge length to obtain, its test method has also been omitted the precompressed program of concrete sample except changing the gauge length of measuring distortion.Because the change of these conditions makes the test findings of elastic modulus differ bigger---the elastic mould value of full gauge length only is about 1/10th of standard method.Learn from the contrast test achievement of phase one, do not carry out the precompressed elastic modulus and reduce and to be about 10%, and use just Accounting 80% nearly of reduction value that full gauge length makes elastic modulus instead.In the experimental study practice, also find, when carrying out elasticity modulus test according to standard method, because the intensity of plastic concrete is lower, the set screw of fixation measuring gauge length needs more being screwed into could keep measuring the stable of Deformable rack in the concrete substantially, this has destroyed the lower inner structure of the original intensity in this position to a certain extent, the gauge length of measuring test piece deformation then carries out on this basis, therefore, be understood that this factor is big to the influence of measuring deformation result---be almost 8 times of full gauge length measurement result.Moreover, because the outwardness of concrete inhomogeneity can think that the value of full gauge length measurement distortion should be more representative than the deformation values that adopts local size.So the deformation values that adopts the full gauge length of 300mm to measure plastic concrete carries out the test method of calculating elastic modulus also just should be more reasonable.
The physical significance of elasticity modulus of materials is the ratio of stress and strain, and the elastic modulus of rigid material generally is to adopt the slope of straight-line segment to represent that the normal concrete of pairing approximation rigidity then is that the secant slope when getting 40% failing load is represented.Because the distortion of plastic concrete is bigger, straight-line segment determine to tend to vary with each individual the generation error, so, when in this experimental study, considering the test result of calculating elastic modulus, passed through comparison and balance repeatedly, final definite average elasticity modulus of 10%～90% failing load that adopts is represented, to reduce artificial error.But so computing method seem comparatively loaded down with trivial details in actual application, do not meet accurately yet, simply, principle efficiently, more be unfavorable for application.For this reason, through calculating relatively, the average elasticity modulus value of finding 10%～90% failing load is comparatively approaching with the secant Young's modulus value of getting failing load 40%, if the slope of the secant of employing 40% is represented the elastic modulus of plastic concrete, except gauge length difference and cancellation precompressed that test is adopted, also has the stress of rejecting 0.5MPa in computing formula and the computation process of corresponding strain, other program is just just the same with the test method of standard, so not only can simplify the test method of plastic concrete elastic modulus, and compare with standard method, the change of test procedure is also little, abbreviates ' full gauge length bullet ' as.The difference of the elastic modulus that calculates for these two kinds of methods relatively, according to table 8,9,10 test findings, 150 * 150 * 300mm standard specimen (K1～K28) and the non-standard test specimen of φ 150 * 300mm (K11～' nonstandard 300 bullets ' K28) and the result of ' full gauge length bullet ' contrast and error analysis in table 11, have been listed in.
The error analysis table (MPa) of table 11 ' nonstandard 300 bullets ' and ' full gauge length bullet '
From the computational analysis of table 11 as can be seen both average error be about 4.0% and 5.3% only, illustrate that the slope of the secant that adopts failing load 40% represents that the elastic modulus of plastic concrete should be feasible, and test method has quick and characteristic of simple.
In addition, utilize table 9,10 test result, the ratio that can obtain the axial compressive strength of the non-standard test specimen of φ 150 * 300mm and 150 * 150 * 300mm standard specimen is about 0.9, statistical computation the results are shown in Table 12:
The ratio of table 12 φ 150 * 300mm and 150 * 150 * 300mm axial compressive strength (MPa)
Annotate: the elastic modulus of triaxial test is represented with the secant slope of 0.4 failing load.
5.3 test result analysis
From the test result of table 12 as can be seen:
1. the elastic modulus that obtains according to the test method of ' full gauge length bullet ' differs less with ' nonstandard 300 bullets ', and its error is cubical to be 3.2%, and cylindrical is 3.0%, and its statistical study sees the following form:
The error analysis (MPa) of table 14 ' nonstandard 300 bullets ' and ' full gauge length bullet '
2. ' nonstandard 300 bullets ' that adopt the non-standard test specimen of φ 150 * 300mm and 150 * 150 * 300mm standard specimen are respectively 82.0% and 78.5% with the ratio of ' full gauge length bullet ', the elastic modulus of non-standard test specimen that has proved employing φ 150 * 300mm once more is less than 150 * 150 * 300mm standard specimen, its ratio is between 78.5～82%, and result of calculation sees Table 15:
The ratio (MPa) of non-standard test specimen of table 15 and standard specimen elastic modulus
3. as can be seen, along with confined pressure σ from the achievement of triaxial test
3Raising, the axial compressive strength of plastic concrete shows a rising trend, σ
3When 0 increased to 0.7MPa, intensity was increased to 3.06MPa from 1.73MPa, has improved 77%.And the raising of elastic modulus is little: σ
3When 0 increased to 0.1MPa, 0.4MPa and 0.7MPa respectively, elastic modulus was respectively 257MPa, 271MPa, 311MPa and 296MPa, and amplification is 5%, 21% and 15%.Compare with axial compressive strength, the increasing degree of elastic modulus is less, and regularity meets document
Annotate (3)Introduction.Simultaneously also proved plastic concrete once more under three conditions, intensity is with σ
3Increase and improve, and the little characteristic of elastic modulus amplification, this characteristic is very favorable to the safety of plastic concrete cut-pff wall and the assurance of antiseepage function just.
4. ' stress-strain ' curve from triaxial test it can also be seen that, along with confined pressure σ
3Raising, ' stress-strain ' curve almost becomes straight line, ' nonstandard 300 of K31
CircleBullet ' with the σ of triaxial test
3Be 0, the stress-strain diagram of 0.1MPa, 0.4MPa and 0.7MPa sees Fig. 3,4,5,6,7:
6. the research of plastic concrete compressive strength and elastic modulus, infiltration coefficient relation
In the technical indicator of cut-pff wall plastic concrete, generally has the designing requirement of compressive strength, elastic modulus and infiltration coefficient simultaneously.To this,, the mutual relationship of compressive strength, elastic modulus and the infiltration coefficient of plastic concrete is analyzed by the achievement of this experimental study.
Make cement, clay T and bentonitic clay P be generically and collectively referred to as Binder Materials B, utilize the testing data of table 9 in the subordinate phase experimental study process, by multiple regression compressive strength R, elastic modulus E and the coefficient of permeability K of plastic concrete and cement ratio B/W or water-cement ratio W/B, clay volume T/B and bentonitic clay volume P/B are carried out quantitative test, and set up corresponding relational expression and represent mutual relation.Wherein, the relational expression of compressive strength sees that formula is 1.:
R=6.44B/W-7.40T/B-11.85P/B+0.47............ formula 1.
N=10 multiple correlation coefficient r=0.961＞r
0.01The relational expression of=0.758 residual standard deviation s=0.58MPa elastic modulus sees that formula is 2.:
E=535B/W-3213T/B-4486P/B+2144............ formula 2.
N=10 multiple correlation coefficient r=0.953＞r
0.01The relational expression of=0.758 residual standard deviation s=155MPa infiltration coefficient sees that formula is 3.:
K=10.2W/B-6.3T/B-9.2P/B-4.6............ formula 3.
N=10 multiple correlation coefficient r=0.764＞r
0.01=0.758 residual standard deviation s=0.97 * 10
-7
The conclusion of above multiple regression analysis shows:
1. from the multiple correlation coefficient r of three formula all greater than r
0.01, having illustrated that the linear relationship of compressive strength, elastic modulus and the infiltration coefficient of plastic concrete and cement ratio or water-cement ratio, clay volume and bentonitic clay volume is comparatively close, its relational expression can be reacted their mutual relations preferably; Bigger than normal from residual standard deviation, the fluctuation that also reflects test index is bigger.
2. as can be seen, the compressive strength of plastic concrete improves with the increase of cement ratio (reciprocal each other with water-cement ratio), reduces with the increase of clay volume and bentonitic clay volume, wherein, bentoniticly falls strong rate greater than clay from strength formula.The every increase by 1% of clay volume and bentonitic clay volume, compressive strength reduces 0.074MPa and 0.12MPa respectively.
3. as can be seen, the elastic modulus of plastic concrete improves with the increase of cement ratio, reduces with the increase of clay volume and bentonitic clay volume, and wherein, bentonitic reduced rate is greater than clay from the elastic modulus formula.The every increase by 1% of clay volume and bentonitic clay volume, elastic modulus reduces 32MPa and 45MPa respectively.
4. from the formula of infiltration coefficient as can be seen, the infiltration coefficient of plastic concrete improves with the increase of water-cement ratio, reduces with the increase of clay volume and bentonitic clay volume, and wherein, bentonitic reduced rate is greater than clay.The every increase by 1% of clay volume and bentonitic clay volume, infiltration coefficient reduces by 0.063 * 10 respectively
-7With 0.092 * 10
-7
Carrying out plastic concrete match ratio when design, can utilize three relational expressions that design objective is estimated, and by adjusting water-cement ratio, clay volume and bentonitic clay volume, make the match ratio of plastic concrete satisfy the designing requirement of cut-pff wall.
7. the conclusion of experimental study
By the experimental study of above-mentioned three phases, the match ratio design of plastic concrete and the test method of elastic modulus there have been further understanding:
1. plastic concrete is lower than normal concrete and the bigger characteristics of distortion owing to have intensity, so the test of adopting the test method of normal concrete to carry out elastic modulus exists certain irrationality, can cause the result of test can not reflect the deformation performance and the impervious ability of plastic concrete really, this also is to occur the reason place that design objective is not complementary in causing the cut-pff wall concrete construction at present.
2. the method that adopts full gauge length to measure test piece deformation is carried out the elasticity modulus test of plastic concrete, can avoid causing bigger test error because of fixation measuring distortion support can destroy the lower inner structure of plastic concrete intensity in the standard method, and the elastic mould value that test findings and triaxial test obtain is comparatively approaching, and meets the scope that " water power water conservancy rules concrete cut job specifications " DL/T5199-2004 requires.Therefore, can think that the method that the test of plastic concrete elastic modulus adopts full gauge length to measure test piece deformation is rational, simultaneously, in the cancellation test precompressed program of test specimen is also met the characteristics of plastic concrete, the elastic modulus that obtains can reflect the deformation performance of plastic concrete comparatively really.
3. the slope that adopts full gauge length to measure the distortion of test specimen and get 40% secant simultaneously represent the elastic mould value of plastic concrete---i.e. and the test method of ' gauge length bullet entirely ' helps simplifying the process of the test of plastic concrete elastic modulus.Compare with standard method, except the measurement gauge length and precompressed program that adopt, remaining process of the test is identical; And the calculating of test findings rejected the stress of 0.5MPa and the calculating of dependent variable thereof, makes the test of plastic concrete elastic modulus and calculation process more simple.
4. according to the relevant regulations in the elastic modulus standard test method, be standard specimen with the test specimen of 150 * 150 * 300mm, φ 150 * 300mm's is non-standard test specimen, with the ratio of the area of standard specimen be 0.785.In this experimental study, the test findings of the elastic modulus of non-standard test specimen is all less than standard specimen, and its ratio is between 0.56～0.82.Therefore, in the test method of recommending, regulation adopts the test findings of non-standard test specimen φ 150 * 300mm to multiply by 1.2 elastic modulus that are converted into standard specimen.
5. according to the experimental study achievement, when non-standard test specimen φ 150 * 300mm is converted into the axial compressive strength of standard specimen 150 * 150 * 300mm, should multiply by 1.1 reduction coefficient.
Claims (4)
1. test method of measuring the plastic concrete elastic modulus may further comprise the steps:
(1) makes 3 test specimens by ' moulding of concrete sample and maintenance process ' industry standard;
(2) arrive test during the length of time, test specimen is taken out from fog room, clean the surface and keep the test specimen humidity;
(3) earlier the magnetic force dial framework is installed on the column of testing machine, then clock gauge or displacement transducer is fixed on the magnetic force dial framework; Test specimen to be measured is placed on the lower platen of testing machine, the center of test specimen should with testing machine lower platen centrally aligned; Start testing machine, adjust the testing machine ball seat, top board is contacted evenly with the test specimen surface; Keeping pressing plate to contact but load reads the initial reading of clock gauge or displacement transducer when being 0 state with test specimen;
(4) start testing machine, test, write down the deformation values under the loads at different levels, when the loading load reaches 50% failing load, unload clock gauge or displacement transducer, be depressed into test specimen with identical speed and destroy with the loading speed of 0.2～0.3MPa/s;
(5) be calculated as follows the static(al) pressure-proof elasticity modulus of test specimen, be accurate to 1MPa:
Ec＝(P
1/A)×(L/ΔL)
In the formula: Ec---static(al) pressure-proof elasticity modulus, MPa
P
1---40% failing load, N
L---measure the gauge length of distortion, i.e. the total length of test specimen, mm
The deformation values of Δ L---stress from 0 to 40% failing load, mm
A---test specimen bearing area, mm
2
(6) with the mean value of the static(al) pressure-proof elasticity modulus measured value of three test specimens as test findings.
2. the test method of mensuration plastic concrete elastic modulus according to claim 1 is characterized in that: deformation values 〉=6 under the described loads at different levels.
3. the test method of mensuration plastic concrete elastic modulus according to claim 1 is characterized in that: the specification of test specimen is the prism of 150 * 150 * 300mm.
4. the test method of mensuration plastic concrete elastic modulus according to claim 1, it is characterized in that: when adopting φ 150 * 300mm test specimen to test, it is the elastic modulus of standard specimen 150 * 150 * 300mm that test findings should multiply by 1.2 coefficient conversion.
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4044608A (en) * | 1975-06-05 | 1977-08-30 | A/S Trondhjems Nagle & Spigerfabrik | Method for in situ determination of concrete strength |
-
2010
- 2010-08-10 CN CN2010102497237A patent/CN102116716A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4044608A (en) * | 1975-06-05 | 1977-08-30 | A/S Trondhjems Nagle & Spigerfabrik | Method for in situ determination of concrete strength |
Non-Patent Citations (5)
| Title |
|---|
| 《SL352-2006 水工混凝土试验规程》 20061023 陈改新等 《水工混凝土试验规程》 189-197页 1-4 , * |
| 《水力发电》 20050331 李清富等 《塑性混凝土弹性模量的试验研究》 第30-32页 1-4 第31卷, 第3期 * |
| 《水电工程施工试验与检验》 20030131 国家电力公司水电建设工程质量监督总站 《水电工程施工试验与检验》 第108-109页 1-4 , * |
| 李丽等: ""对防渗墙塑性混凝土弹性模量的讨论"", 《2009年地基基础工程与锚固注浆技术研讨会论文集》 * |
| 高丹盈等: ""塑性混凝土弹性模量的计算方法"", 《郑州大学学报（工学版）》 * |
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