CN105808836A - Method for determining temperature process curve of mass concrete with ultrahigh volume of fly ash - Google Patents

Abstract

The invention discloses a method for determining a temperature process curve of a mass concrete with ultrahigh volume of fly ash. Through adoption of a reference concrete and a concrete with ultrahigh volume of admixture, adiabatic temperature rise tests are carried out; a big cubic test block with side lengths of 1.2m is manufactured for carrying out a temperature measurement test; through combination of the actual measurement temperature records of the internal points of a certain hyperbolic high arch dam A constructed through adoption of the reference concrete, the adiabatic temperature rise models of the two concretes are provided; ANSYS finite element software is improved for carrying out temperature field simulating calculation; verification is carried through utilizing the actual measurement temperature curves of the big test block manufactured by the concrete with ultrahigh volume of admixture and the entity dam of the reference concrete; therefore, the temperature process curve of the dam manufactured by the concrete with ultrahigh volume of admixture is simulated and determined, and there is no construction precedent of the temperature process curve; and the temperature process curve can be used for a temperature-stress test and evaluation of the early-age crack resistance of the mass concrete with ultrahigh volume of fly ash.

Description

The method determining superelevation content fly ash mass concrete temperature course curve

Technical field

The invention belongs to necessary to the Green High Performance hydraulic large-volume concrete temperature-stress test that early age crack resistance is evaluated new Method.

Background technology

Large dosage mineral admixture concrete can be saved cement in a large number, turn waste into wealth, and alleviates environmental pollution, reduces heat of hydration temperature rise With improve its performance.Flyash is still the main admixture of hydraulic large-volume concrete at present.The most built normality dam For concrete dam (non-RCCD), flyash is within high additive is 70%.Volume outside U.S.'s dam is 25%, Inside is then 50%；Japan's high additive is 30%；China's Three Gorges Dam is 20%-50%；" concrete for hydraulic structure mixes powder in China Coal ash technical specification " (DL/T5055-2007) specify that its volume must not exceed 55%.Eight, the nineties, for improving durability And promote the development of high performance concrete, and then promote the application of flyash, especially with high volume fly ash concrete (HVFC) it is First.Canadian Malhotra started the performance of comprehensive system research HVFC equal to 1985.Choose respectively this country 11 kinds, 8 kinds of flyash of the U.S., its volume about 200kg/m³, cement about 150kg/m³(i.e. doping quantity of fly ash accounts for binder total amount 55～60%), through mixing high efficiency water reducing agent water-cement ratio is down to 0.30～0.32, the HVFC prepared, workability is about 200mm, meets pumping construction requirement.It has mechanics and resistance of chloride ion penetration, freeze thawing resistance circulation ability, the erosion resistant of excellence Property etc., the important engineering such as basis having been used for the caisson pile of Wharf Engineering, the beam of civil buildings, plate, post, satellite launch platform, Research and application HVFC are significant.But Malhotra et al. no research temperature impact on its performance.From the most existing In the research of some HVFC, still there is a following deficiency: I in (1) engineering, II grade of ash application are more, but substantial amounts of rudimentary grey Less than utilization.(2) occupy height because of water-cement ratio, make doping quantity of fly ash can not improve.(3) test that for want of " HVFC " is correct Technology and evaluation criterion, it is impossible to the accurately effect of estimated temperature, also limit doping quantity of fly ash.China's dam concrete is still used at present Limit stretch value and adiabatic temperature rise or " the permission temperature difference " evaluate its crack resistance, prevent thermal crack at early stage be by test its adiabatic temperature rise, Parameter determination raw material and the match ratios such as hydration heat of cement, and take pre-cooling to mix and stir, bury the controlling measurement internal-external temperature differences such as cold water pipe underground, Reducing maximum temperature rise, " the permission temperature difference " is from field experience as far as possible.And " the permission temperature difference " of the suggestion of ACI207 committee should It is relevant with the age of concrete, tensile strength, elastic modelling quantity, thermal coefficient of expansion, component degree of restraint etc..Academia both at home and abroad The new method of testing of Exploration and application modern times positive with engineering circles prediction thermal stress in early days, substitutes the old side at present with field experience as foundation Method, to solve the technical barrier of early-age cracking.Temperature-stress test is that the new of research concrete early age crack resistance has efficacious prescriptions Method.

Concrete temperature-stress test has thermal insulation, constant temperature and three kinds of temperature models of Temperature Matching maintenance (TMC).With adiabatic model Concrete riper on the basis of, control time and the rate of temperature fall of the cooling of constant temperature and Temperature Matching mode condition lower on-test. Result shows: adiabatic model has been over-evaluated initial cooling point, underestimated the anti-crack ability of concrete, and constant temperature mode can not embody temperature rise Produce the impact of compressive pre-stress, concrete cracking temperature is on the low side；Only the objective embodiment temperature history of Temperature Matching pattern energy is to reality Border works stress and the impact of Cracking Temperature.

But superelevation content fly ash normality dam concrete (hereinafter referred to as " superelevation adding Concrete ") not yet applies to actual dam In engineering, just it is difficult to study as the Temperature Matching condition of temperature-stress test with the dam concrete temperature history curve surveyed With evaluate its early age crack resistance.Therefore, based on test and finite element simulation simulation determine have no precedent construction precedent " superelevation Adding Concrete " the temperature history curve of dam is most important, evaluates its early age crack resistance for temperature-stress test.

Summary of the invention

It is contemplated that on the basis of prior art, propose to have no precedent the adiabatic temperature rise of " the superelevation adding Concrete " of construction precedent The new method that model and temperature history curve determine.The inventive method is Green High Performance hydraulic large-volume concrete early age cracking resistance Property evaluate necessary new method, can be used widely in Hydraulic structure Material and Structural Engineering.

The present invention is achieved in that

The present invention carries out the normality dam concrete (" normal concrete ") of 35% doping quantity of fly ash and the super of 80% doping quantity of fly ash The adiabatic temperature rise test of high-content fly ash normality dam concrete (" superelevation adding Concrete "), the length of side are that the superelevation of 1.2m is mixed The cube big test block thermometric test of concrete, combines the inside of employing " normal concrete " built certain hyperbolic induced joint A Point observed temperature record, proposes the adiabatic temperature rise model of two kinds of concrete, improves temperature based on ANSYS finite element software with this Field emulation, thus simulation determines the temperature history curve of " superelevation adding Concrete " dam having no precedent construction precedent, for warm Its early age crack resistance is evaluated in degree-stress test.

The technical solution used in the present invention is:

The method determining superelevation adding Concrete temperature history curve based on test and finite element simulation, comprises the steps:

(1) be selected to represent purpose project and meet the raw material of national standard as test raw material prepare two kinds flyash mixed Measure different concrete: the most common 42.5 portland cements of China, Jingmen III level flyash, fine aggregate is artificial sand, coarse aggregate Artificial rubble for maximum diameter of aggrogate 40mm.Its match ratio is shown in Table 1:

The match ratio of the dam concrete of 1 two kinds of different doping quantity of fly ash of table

Make " normal concrete " test specimen and " superelevation adding Concrete " test specimen, carry out the adiabatic temperature of two kinds of concrete samples respectively Rise test；Make the 1.2m length of side " superelevation adding Concrete " big test block of cube, lay point for measuring temperature therein, test its from Enter the age morning temperature history curve that mould starts；To the entity dam built with " normal concrete ", bury temperature sensor underground and survey Try the temperature history curve of its internal point；

(2) the adiabatic temperature rise model of concrete is particularly significant in the temperature field of simulation concrete component and structure.Based on " superelevation Adding Concrete " adiabatic temperature rise test, the adiabatic temperature rise model being applicable to " superelevation adding Concrete " and really of a kind of improvement is proposed Its parameter value fixed, for its big test specimen and the finite element modelling in dam temperature field；And adiabatic temperature based on " normal concrete " Rise test, propose the adiabatic temperature rise model being applicable to " normal concrete " of a kind of improvement and determine its parameter value, for dam Finite Element Simulation of Temperature；

21) according to method two kinds of concrete of test of 4.17 in " concrete for hydraulic structure testing regulations " (DL/T5150-2001) Adiabatic temperature rise curve；

22) step 21 is utilized) the adiabatic temperature rise curve that obtains, determine the exhausted of two kinds of dam concretes with MATLAB software matching The function expression (1) of hot temperature rise, the parameter of (2), as shown in table 2, table 3；

$\mathrm{\θ}\left(\mathrm{\τ}\right)=\frac{p\mathrm{\τ}}{m+\mathrm{\τ}}+\frac{q\mathrm{\τ}}{n+\mathrm{\τ}}---\left(1\right)$

$\mathrm{\θ}\left(\mathrm{\τ}\right)=p(1-e^{-{\mathrm{a\τ}}^b})+\frac{q\mathrm{\τ}}{n+\mathrm{\τ}}---\left(2\right)$

In formula: θ (τ) Adiabatic temperature rise of concrete, DEG C；

The age of τ concrete, sky；

M, n, p, q, a, b undetermined coefficient.

The table 2 adiabatic temperature rise model parameter of the normal concrete of adiabatic temperature rise test data fitting

Formula	p	a	b	q	m	n
							(1)	10.75			15.00	1.809	0.010
(2)	13.00	31.344	24.733	12.51		1.246

The table 3 adiabatic temperature rise model parameter of the superelevation adding Concrete of adiabatic temperature rise test data fitting

Formula	p	a	b	q	m	n
							(1)	7.77			7.91	0.857	0.857
(2)	7.622	0.020	7.108	7.305		0.580

Warp and the relative analysis of actual measurement adiabatic temperature rise curve, the adiabatic temperature rise curve representation formula obtaining two kinds of concrete is respectively as follows:

Normal concrete: $\mathrm{\θ}\left(\mathrm{\τ}\right)=\frac{10.75\mathrm{\τ}}{1.809+\mathrm{\τ}}+\frac{15.00\mathrm{\τ}}{0.01+\mathrm{\τ}}---\left(3\right)$

Superelevation adding Concrete: $\mathrm{\θ}\left(\mathrm{\τ}\right)=7.622(1-e^{-0.02{\mathrm{\τ}}^{7.108}})+\frac{7.305\mathrm{\τ}}{0.58+\mathrm{\τ}}---\left(4\right)$

(3) carry out the temperature field of analogue simulation concrete component and structure based on ANSYS finite element software, by improve " superelevation is mixed Concrete " adiabatic temperature rise model and the adiabatic temperature rise model of " normal concrete " of improvement improve Temperature Field Simulation and calculate； (4) by the adiabatic temperature rise model refinement ANSYS finite element software of " the superelevation adding Concrete " improved, calculating simulation superelevation blends The temperature history curve of solidifying soil cube big test block point for measuring temperature, contrasts with step (1) measured curve, and result is coincide, and explanation changes Enter the suitability of adiabatic temperature rise model；The entity dam built for " normal concrete ", by " normal concrete " that improve Adiabatic temperature rise model refinement ANSYS finite element software, the temperature history curve that calculating simulation goes out and actual dam engineering are surveyed Temperature history curves is good, it was demonstrated that the suitability of the Temperature Field Simulation program of improvement；Thus simulate and have no precedent construction precedent The temperature history curve of superelevation adding Concrete dam, evaluate its early age crack resistance for temperature-stress test.

The present invention has following benefit compared with prior art:

1. model is accurate.The adiabatic temperature rise computing formula of original normal concrete is no longer desirable for " superelevation adding Concrete ", this The improvement adiabatic temperature rise model of invention proposition and computing formula meet the practical situation of material, can improve the essence that Temperature Field Simulation calculates Degree.

2. application is wide.Adiabatic temperature rise model proposed by the invention and the determination method of temperature history curve are applicable not only to superelevation Fly ash normal concrete dam, is also applied for other superelevation fly ash mass concrete engineerings, only need to adjust model system Count and improve the parameter of corresponding ANSYS finite element modelling Temperature Field Simulation.

3. Green High Performance.This method is for solving the adiabatic temperature rise model of superelevation adding Concrete and the determination of temperature history curve, And then evaluate its early age crack resistance for temperature-stress test, the mineral admixture of high additive as far as possible can be applied in engineering (flyash etc.), utilize industrial waste, reduce Portland cement consumption as much as possible, accomplish environmental protection.It addition, powder Coal ash volume is the highest, and concrete temperature rise etc. is the least, and age morning crack resistance and durability to large volume concrete structural the most extremely have Profit.

Accompanying drawing explanation

Fig. 1 is superelevation adding Concrete of the present invention big test block point for measuring temperature schematic diagram；

Fig. 2 is the adiabatic temperature rise curve comparison figure with matching of two kinds of concrete actual measurements of the present invention；

Fig. 3 is superelevation adding Concrete thermometric of the present invention big test block FEM (finite element) model；

Fig. 4 is the FEM (finite element) model of dome dam A monolith of the present invention；

Fig. 5 is the temperature history curve comparison figure with actual measurement of simulation at the point for measuring temperature of superelevation adding Concrete of the present invention big test block center；

Temperature history curve comparison figure that is that Fig. 6 is dome dam internal point normal concrete of the present invention simulation and that survey；

Fig. 7 is the temperature history curve that the analogue simulation of two kinds of concrete of the present invention determines.

Detailed description of the invention

Presented below present invention determine that the new of superelevation fly ash hydraulic large-volume concrete adiabatic temperature rise model and temperature history curve The embodiment of method.

Example:

1. " superelevation adding Concrete " test

1.1 test raw material and match ratios

This test two kinds of concrete of preparation, " normal concrete " uses the dam concrete raw material of dome dam A and construction to join Composition and division in a proportion.Two kinds of different doping quantity of fly ash concrete " normal concrete " (35% doping quantity of fly ash) and " superelevation adding Concrete " (80% Doping quantity of fly ash).The raw material of test is the raw material that dome dam A uses: the most common 42.5 portland cements of China, Jingmen III level flyash, fine aggregate is artificial sand, and coarse aggregate is the artificial rubble of maximum diameter of aggrogate 40mm.Its match ratio is shown in Table 1:

The match ratio of the dam concrete of 1 two kinds of different doping quantity of fly ash of table

1.2 test

(1) the adiabatic temperature rise test specimen of two kinds of doped fly ash concretes is made, according to " concrete for hydraulic structure testing regulations " (DL/T5150-2001) the adiabatic temperature rise curve of method two kinds of concrete of test of 4.17 in.

(2) make " superelevation adding Concrete " big test block of cube that the length of side is 1.2m, lay point for measuring temperature, thermometric therein Point is shown in Fig. 1.Test it from entering the age morning temperature history that mould starts, i.e. temperature-age curve.

Adiabatic temperature rise of concrete model typically represents frequently with index, hyperbola and complex indexes formula.Because doping quantity of fly ash is relatively low Concrete, hydrated cementitious heat release is fast, and index and hyperbolic model can preferably simulate its adiabatic temperature rise curve.If by above-mentioned two formulas The adiabatic temperature rise curve of simulation superelevation adding Concrete, error is bigger.The present invention expresses according to hyperbolic function and Taylor coefficients Formula, the adiabatic temperature rise model expression proposing two kinds of dam concretes is as follows:

$\mathrm{\θ}\left(\mathrm{\τ}\right)=\frac{p\mathrm{\τ}}{m+\mathrm{\τ}}+\frac{q\mathrm{\τ}}{n+\mathrm{\τ}}---\left(1\right)$

$\mathrm{\θ}\left(\mathrm{\τ}\right)=p(1-e^{-{\mathrm{a\τ}}^b})+\frac{q\mathrm{\τ}}{n+\mathrm{\τ}}---\left(2\right)$

In formula: θ (τ) Adiabatic temperature rise of concrete, DEG C；

The age of τ concrete, sky；

The coefficient that m, n, p, q, a, b are undetermined.

Formula (1) and formula (2) can more flexible simulation concrete exactly actual hydration heat process, thus difference is preferably described The adiabatic temperature rise curve of concrete material.

The present invention uses formula (1) and (2), in conjunction with the adiabatic temperature rise test data of two kinds of doping quantity of fly ash concrete, and will test Data are input in MATLAB software, more respectively formula (1) and (2) are input in MATLAB, intend with MATLAB software Closing and determine the relevant parameter in each function expression, each parameter value obtained the results are shown in Table 2 and 3.Thus contrast acquisition two kinds mixes The adiabatic temperature rise function expression of solidifying soil.

The table 2 adiabatic temperature rise model parameter of the normal concrete of adiabatic temperature rise test data fitting

Formula	p	a	b	q	m	n
							(1)	10.75			15.00	1.809	0.010
(2)	13.00	31.344	24.733	12.51		1.246

The table 3 adiabatic temperature rise model parameter of the superelevation adding Concrete of adiabatic temperature rise test data fitting

Formula	p	a	b	q	m	n
							(1)	7.77			7.91	0.857	0.857
(2)	7.622	0.020	7.108	7.305		0.580

Analyzed by the matched curve of the measured curve of the adiabatic temperature rise of two kinds of concrete with formula (1) and (2), can obtain: The result of adiabatic temperature rise curve formula (1) matching of normal concrete is the most identical with measured curve；The thermal insulation of superelevation adding Concrete The result of temperature rise curve formula (2) matching is the most identical with measured curve.Therefore the adiabatic temperature rise model of normal concrete uses public affairs Formula (1), the adiabatic temperature rise model of superelevation adding Concrete uses formula (2).Two kinds of concrete matchings and the adiabatic temperature rise of actual measurement Curve comparison figure is shown in Fig. 2.

The adiabatic temperature rise curve representation formula of the two kinds of concrete obtained is respectively as follows:

Normal concrete: $\mathrm{\θ}\left(\mathrm{\τ}\right)=\frac{10.75\mathrm{\τ}}{1.809+\mathrm{\τ}}+\frac{15.00\mathrm{\τ}}{0.01+\mathrm{\τ}}---\left(3\right)$

Superelevation adding Concrete: $\mathrm{\θ}\left(\mathrm{\τ}\right)=7.622(1-e^{-0.02{\mathrm{\τ}}^{7.108}})+\frac{7.305\mathrm{\τ}}{0.58+\mathrm{\τ}}---\left(4\right)$

3. the Temperature Field Simulation of superelevation adding Concrete and determine temperature history curve

3.1 the method determining temperature history curve based on ANSYS finite element software

3.1.1 research method and analysis process

This calculating utilizes ANSYS software to carry out dome dam A monolith and the length of side for the 1.2m big test block of superelevation adding Concrete Temperature Field Simulation computational analysis.Idiographic flow is as follows:

(1) data collection: include engineering meteorological model data, dam boy shape, thermodynamic parameter, project progress, working measure Deng.

(2) finishing analysis data: parameter fitting, method for analyzing and modeling.

(3) modeling: use ANSYS software to be modeled, grid division.

(4) calculating batch program is write: write the ANSYS batch program calculating temperature field according to data combination model.

(5) check calculating batch program: first check for statement, be then introduced into computation model and check added load effect.

(6) temperature is calculated: use ANSYS software temperature to calculate module and calculate.

(7) analysis temperature result: the thermo parameters method in Main Analysis each moment and representative temperature eigenvalue.

3.1.2 pre-treatment

(1) model is set up

This modeling employing dome dam A monolith and the big test block of cube that the length of side is 1.2m.

(2) stratified construction simulation

The big test block of 1.2m cube in this test, because its floor height is relatively low, uses one-time-concreting complete.Dome dam A according to It is that 1.5m mono-layer pours that design requires at confining region, rather than confining region uses 3m floor height to pour.

(3) parameter is chosen

Parameter is typically chosen the materials testing report of application for developing, if project management department is not provided that these data, and can be by consulting phase Close document, take the data of Sinilar engineering as far as possible.It is actual that data in this test both are from engineering.

3.1.3 calculate

(1) ANSYS computing module

ANSYS calculates temperature field module and is carried by it, can be directly entered module and calculate.

(2) chemistry heat production simulation

Simulated by heat production order BFE in ANSYS.

(3) boundary condition imitation

Convection boundary condition is simulated by order SFA, and contact heat radiation boundary condition is simulated by order D.

(4) simulation is poured

By the Life-and-death element functional realiey in ANSYS, starting stage all unit are dead unit, and dead unit acquiescence plays mould Being a value the least, it does not the most affect for the mechanical property of structure.The first step first activates ground, recovers original material Material attribute；Elapse then as the time, activate the concrete that each layer pours, simulate casting process with this.

(5) computational methods

Calculating by internal heat production and the interaction of external boundary condition, calculating heat, in the transfer process of material internal, obtains Thermo parameters method the most in the same time.

3.1.4 post processing

Required point is taken as respectively feature node, and draws function by duration curve in ANSYS, draw its characteristic point Temperature variation curve and thermo parameters method, judge simulation analysis whether reasonable according to its Changing Pattern.This experiment is chosen Bottom dome dam A monolith, in the middle part of 22.5m, point and big test block center point carry out duration curve drawing as characteristic point.

3.2 temperature histories using the adiabatic temperature rise model emulation simulation big test block of superelevation adding Concrete improved

With the temperature history that the above-mentioned Temperature Field Simulation program simulation superelevation adding Concrete length of side is 1.2m cube big test block point for measuring temperature. The FEM (finite element) model such as Fig. 3 set up.

In Fig. 3, the length of side is the big test block of cube of 1.2m, and bottom is the ground calculating conduction of heat needed for simulated program.With 10cm The regular hexahedron of the length of side is that unit carries out element subdivision.The adiabatic temperature rise model of superelevation adding Concrete uses formula (4), ANSYS The adiabatic temperature rise of middle concrete passes through heat generation rate H_genRealizing, heat generation rate is the heat amount of unit volume concrete in the unit interval, I.e. give birth to the derivative of heat-versus-time, be represented by:

$H_{gen}=\frac{dQ}{d\mathrm{\τ}}---\left(5\right)$

In formula: Q is the heat that concrete produces；H_genHeat of hydration rate for concrete.

The heat Q that concrete produces can be obtained by following formula again:

Q=θ (τ) c ρ (6)

In formula: θ (τ) is thermal insulation temperature rise；C is specific heat；ρ is concrete density.

Relational expression by the available heat generation rate of formula (5) and formula (6) and thermal insulation temperature rise is as follows:

$H_{\mathrm{gen}}=\frac{\mathrm{dQ}}{\mathrm{d\τ}}=\frac{d\left[\mathrm{\θ}\left(\mathrm{\τ}\right)\mathrm{c\ρ}\right]}{\mathrm{d\τ}}=\mathrm{\θ}\′\left(\mathrm{\τ}\right)\mathrm{c\ρ}---\left(7\right)$

Just can be determined the heat generation rate of concrete by the adiabatic temperature rise pattern function that we improve according to formula (7).

The adiabatic temperature rise model expression improved is converted into heat generation rate according to formula (7) be input in ANSYS calculate superelevation and blend solidifying The temperature field of the big test block of soil.Draw function by duration curve in ANSYS, draw big test block central point temperature duration curve, I.e. simulate the temperature history curve of big test block temperature point, with temperature history curve comparison figure such as Fig. 5 of this measuring point of actual measurement. As seen from the figure, the temperature history curve of superelevation adding Concrete cube big test block simulation and actual measurement is more identical, and the thermal insulation proposed is described Temperature Rise Model is suitable for the Temperature Field Simulation of superelevation adding Concrete and calculates.

But observed temperature course curve is affected greatly by outside air temperature, rise gentle temperature-fall period inconspicuous.For avoiding test block thermometric by outward The interference of boundary's temperature, should take measures to make to obtain more preferable adiabatic environment inside big test block to obtain closer to material self character Temperature history curve.

The temperature history curve of 3.3 temperature simulation simulation arch dam A monolith internal point

Built hyperbolic induced joint A construction is normal concrete, buries temperature measurer in advance underground, record its temperature and go through inside this dam Journey curve.Its FEM (finite element) model is as shown in Figure 4.At 3m LIFT concrete center representative at 22.5m at the bottom of dam, There is the temperature history curve of actual measurement, this position is also served as the calculating point in temperature field simultaneously.

ANSYS is used to model this monolith to calculate temperature field.Fig. 6 is that dome dam A internal point normal concrete is surveyed and mould The temperature history curve comparison figure intended.As seen from Figure 6, the temperature history of dome dam normal concrete simulation calculation and actual measurement is bent Line is consistent, illustrates that dome dam temperature is imitated by the adiabatic temperature rise model improved that uses of the present invention to improve ANSYS finite element software The reasonability of true simulation and accuracy.The temperature field of the available ANSYS finite element software simulation calculation superelevation adding Concrete improved.

The temperature history curve of the superelevation adding Concrete dam of precedent of the most not constructing, than normal concrete, during analogue simulation The two uses identical dam body position, monolith model and arrangement and method for construction etc., but adiabatic temperature rise model is different, and this point shows as at ANSYS The heat generation rate H of middle input_genDifferent.The adiabatic temperature rise model of two kinds of concrete by improving, improves ANSYS finite element software Temperature Field Simulation, all take in built hyperbolic height A certain monolith and mix at 3m LIFT representative at 22.5m at the bottom of dam Ning Tu center, for calculating point, obtains the temperature history curve of two kinds of concrete with this, sees Fig. 7.

Temperature history curve under 3.4 superelevation adding Concrete Temperature Matching (TMC) patterns

The temperature history curve of the superelevation adding Concrete of temperature simulation program calculating simulation, can be as under Temperature Matching (TMC) pattern The guiding curve of temperature-stress test carries out temperature-stress test (TSTM test), it is thus achieved that the thing of superelevation adding Concrete early age Reason mechanical property, is used for studying and evaluate its early age crack resistance.

Claims (1)

1. the method determining superelevation content fly ash mass concrete temperature course curve, described method includes Following steps:

(1) it is selected to represent purpose project and meet the raw material of national standard as test raw material, making " base Quasi-concrete " test specimen and " superelevation adding Concrete " test specimen, carry out the adiabatic temperature rise of two kinds of concrete samples respectively Test；Make " superelevation adding Concrete " big test block of cube of the 1.2m length of side, lay point for measuring temperature therein, Test it from entering the age morning temperature history curve that mould starts；To the entity dam built with " normal concrete ", Bury temperature sensor underground and test the temperature history curve of its internal point；

Prepare two kinds of concrete, " normal concrete " use the dam concrete of dome dam A raw material and Coordination in works.Two kinds of different doping quantity of fly ash concrete " normal concrete " (35% doping quantity of fly ash) and The raw material that " superelevation adding Concrete " (80% doping quantity of fly ash) is tested is the raw material that dome dam A uses: The most common 42.5 portland cements of China, Jingmen III level flyash, fine aggregate is artificial sand, and coarse aggregate is The artificial rubble of big aggregate size 40mm.Its match ratio is shown in Table 1:

The match ratio of the dam concrete of 1 two kinds of different doping quantity of fly ash of table

(2) adiabatic temperature rise based on " superelevation adding Concrete " test, propose a kind of improvement is applicable to that " superelevation is mixed Concrete " adiabatic temperature rise model and determine its parameter value, have for the temperature field of the big test block of dam and cube The simulation of limit unit；And adiabatic temperature rise based on " normal concrete " is tested, and propose a kind of improvement is applicable to " base Quasi-concrete " adiabatic temperature rise model and determine its parameter value, for dam Finite Element Simulation of Temperature；

21) according to the method test two of 4.17 in " concrete for hydraulic structure testing regulations " (DL/T5150-2001) Plant the adiabatic temperature rise curve of concrete；

22) step 21 is utilized) the adiabatic temperature rise curve that obtains, determine two kinds of dams with MATLAB software matching The function expression (1) of the adiabatic temperature rise of concrete, the parameter of (2), as shown in table 2, table 3；

$\mathrm{\θ}\left(\mathrm{\τ}\right)=\frac{p\mathrm{\τ}}{m+\mathrm{\τ}}+\frac{q\mathrm{\τ}}{n+\mathrm{\τ}}---\left(1\right)$

$\mathrm{\θ}\left(\mathrm{\τ}\right)=p(1-e^{-{\mathrm{a\τ}}^b})+\frac{q\mathrm{\τ}}{n+\mathrm{\τ}}---\left(2\right)$

In formula: θ (τ) Adiabatic temperature rise of concrete, DEG C；

The age of τ concrete, sky；

M, n, p, q, a, b undetermined coefficient.

The table 2 adiabatic temperature rise model parameter of the normal concrete of adiabatic temperature rise test data fitting

The table 3 adiabatic temperature rise model parameter of the superelevation adding Concrete of adiabatic temperature rise test data fitting

By the relative analysis with respective actual measurement adiabatic temperature rise curve, the adiabatic temperature rise obtaining two kinds of concrete is bent Line expression formula:

Normal concrete:

Superelevation adding Concrete:

(3) by improve the adiabatic temperature rise model being applicable to " superelevation adding Concrete " and improvement be applicable to " base Quasi-concrete " adiabatic temperature rise model improve Temperature Field Simulation calculate.Emulate based on ANSYS finite element software Calculate dam concrete component and the temperature field of structure.

(4) by the adiabatic temperature rise model of " the superelevation adding Concrete " improved, simulate based on ANSYS finite element software The temperature history curve of the superelevation adding Concrete cube big test block point for measuring temperature gone out, with step (1) measured curve Contrast, result is coincide good, illustrates to improve the suitability of adiabatic temperature rise model；" normal concrete " is built The entity dam made is by the adiabatic temperature rise model of " normal concrete " improved, soft based on ANSYS finite element The temperature history curves that the temperature history curve that part simulates and actual dam engineering are surveyed is good, it was demonstrated that improve The suitability of dam Temperature Field Simulation program；By the adiabatic temperature rise model of " the superelevation adding Concrete " improved, The temperature of " superelevation adding Concrete " dam having no precedent construction precedent is simulated based on ANSYS finite element software Course curve, studies for temperature-stress test and evaluates superelevation content fly ash hydraulic large-volume concrete Early age crack resistance.