CN101685059B - Method for dynamically detecting rheological property of concrete on construction site - Google Patents

Abstract

The invention discloses a method for dynamically detecting rheological property of concrete on a construction site. The method comprises the following steps: firstly, mounting a debugging test instrument; then, starting sampling to automatically acquire a mixture test sample from a concrete discharging port, testing the temperature Tj of the acquired concrete mixture test sample, averaging the temperature to obtain Tj, continuously acquiring a plurality of groups of {Mji, ni and Tj}, and storing the acquired data in a singlechip; finally, carrying out data analysis, and working out [tau]ji according to the Mji; working out [gamma]i according to the ni; respectively averaging [tau]ji data calculated at the corresponding i-gear rotating speed ni in j test samples, drawing a concrete rheological curve diagram and a concrete thixotropic hysteresis curve diagram according to the relation of [gamma]i-[tau]ji, and obtaining a straight line [tau]ji= [tau]0+[eta]p[gamma]i through curve fittingso as to obtain {[tau]0, [eta]p and Tj}, wherein the [tau]0 is the shearing strength yielding value of the fluid concrete before pouring under the condition of Tj, and the [eta]p is the plastic viscosity of slurry under the condition of Tj; and obtaining upper and lower curve functions f1([gamma]i) and f2([gamma]i) through the curve fitting, and obtaining the area S of a concrete hysteresis loop by integrating to analyze the thixotropic property of the fluid concrete.

Description

Method for dynamically detecting rheological property of concrete on construction site

Technical field

The present invention relates to chutable concrete rheology testing field, specifically relate to the detection method and the device thereof of rheological property of concrete on construction site energy.

Background technology

To concrete rheological test of fluidised form and evaluation is one of important step of concrete Quality Control always.Chutable concrete belongs to non-Newtonian fluid, wherein two rheological parameters the most basic: the shear stress yield value τ of slurry ₀Plastic viscosity η with slurry _pIt is the leading indicator of reflection concrete mortar rheological.Working-yard use at present also is at most that the method for the test rheological property of concrete of most convenient is the slump test.Estimate concrete rheological with slump and exist many defectives: its only suitable consistency range is medium plastic to high plastic consistency range 3.8～17.8cm's, and this method is quite responsive to irregular operation, needs certain operation skill; For poor mix, the slump method can not be measured the difference of two kinds of different mixs of denseness; Even if the concrete that slump is identical, stability as segregation, bleeding may be widely different; Also inapplicable to big rheological concrete.Also have in addition test at the construction field (site) that big rheological concrete flow velocity changes as: with L type flow instrument, Orimet current meter etc., but cooperate slump tester or V-B consistometer etc. could judge concrete flowability and serviceability, these method measuring points are few, random error strong, hand-manipulated is big and can't complete objective evaluation to the deposit concrete rheological.

The method that some other novel test rheological property of concrete is also arranged in the engineering practice at present, these methods all are based on the shear stress yield value τ of two-point method principle test chutable concrete ₀Plastic viscosity η with slurry _pBut these testing tools and method can only be obtained a small amount of discrete data at the scene by a small amount of measuring point of manual control random test, and nationality can't accurately be passed judgment on the variation of monolithic concrete rheological to estimate concrete rheological property.

It is the important evidence that the monolithic concrete rheological is passed judgment on that the working-yard can obtain the preceding rheological property of concrete parameter of all cast in real time, and also quality control provides the reliable technique index to Concrete Construction.Obviously rely on above-mentioned all multiple method of testings to satisfy and obtain the complete parameter that the monolithic concrete rheological is passed judgment on, therefore can not objective and accurate evaluation be arranged the rheological property of concrete of cast.

Summary of the invention

In order to overcome the shortcoming that currently used rheological property of concrete means of testing can't accurately be passed judgment on the variation of monolithic concrete rheological, the invention discloses a kind of method for dynamically detecting rheological property of concrete on construction site, can make correct evaluation the sex change of concrete bulk flow.

Technical scheme of the present invention is: a kind of method for dynamically detecting rheological property of concrete on construction site, and step is:

At first, the Installation and Debugging tester when making the magazine of tester move to the sampling location, is sitting at the discharge port below of concrete placement vehicle or pump;

Then, begin sampling, gather the concrete mix sample automatically from the pouring out concrete mouth, the temperature T of concrete mix sample is gathered in test _j, the T to gathering then _jGet arithmetic mean, obtain the temperature of this group J=1 wherein, 2 ... k, j represent the specimen coding of the same batch of required test of concrete, and k is the sample sum of the same batch of required test of concrete, and k is according to concrete needs value; Each sample different rotating speeds n under the follow-on test j sample _iUnder rotation torque M _JiJ=1 wherein, 2 ... k, j, k meaning are the same, i=1,2 ... 11, i is that same sample is by transformation of speed number of times between 60 commentaries on classics/min～200 commentaries on classics/min, such as carrying out transformation of speed 11 times, 11 gears, for example n are arranged just from 60 commentaries on classics/min～90 commentaries on classics/min～120 commentaries on classics/min～150 commentaries on classics/min～180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min～150 commentaries on classics/min～120 commentaries on classics/min～90 commentaries on classics/min～60 commentaries on classics/min ₄4 transformation of speed rotating speed of the 4th grade has just been carried out in expression.In this way continuous acquisition obtains the { M of same batch of concrete mix sample _Ji, n _i,

Some groups, with the data storing of gathering in single-chip microcomputer MSP430.For guaranteeing the working-yard convenient test, in single-chip computer control system, be provided with automatic acquisition and memory system, can store 12 at most, 500 data, can obtain image data continuously, both can online on-line testing, also can be interrupted the read test data, thereby be convenient to the continuous working of Auto-Test System.Wherein, described different rotating speeds ni is meant between the rotating speed of 60 commentaries on classics/min～200 commentaries on classics/min, from low to high, the rotating speed that changes from high to low again is such as by 60 commentariess on classics/min～90 commentaries on classics/min-120 commentaries on classics/min～150 commentaries on classics/min-180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min-150 commentaries on classics/min～120 commentaries on classics/min-90 commentaries on classics/min～60 commentaries on classics/min rotation.

At last, the data transmission that stores in the single-chip microcomputer is carried out data analysis in host computer, according to gained rotary torque M _Ji, by formula

Calculate shear stress τ _Ji, in the formula: the diameter of the cross shaft of D-: h-rotating vane length: M _JiRotary torque during-Di j sample i shelves, π-circular constant; According to rotation speed n _i, by formula:

Calculate shear rate γ _i, R wherein ₁-slip box height, R ₂-rotating vane radius, h-rotating vane length, n _i-Di i shelves rotating speed, derivation of equation process is as follows: rotate j test specimens concrete mix by the driven by motor rotating vane, measure rotating vane in i shelves rotation speed n by torque sensor again _iUnder rotary torque M _Ji, by rotary torque M _JiCan obtain shear stress τ _Ji, derivation is as follows:

The shear surface of cross shaft is regarded as a barrel surface calculate, as Fig. 8, therefore, the face of being sheared calculates according to side and two bottom surfaces, then suffered rotary torque M _JiFor:

Can obtain thus ${\mathrm{\τ}}_{\mathrm{ji}}=\frac{16M_{\mathrm{ji}}}{{\mathrm{\πD}}^2(D+8h)}---\left(1\right)$

In the formula: the diameter of the cross shaft of D-: h-rotating vane length: M _Ji-Di i shelves rotation speed n _iUnder rotary torque, π-3.14;

The shear rate γ of shaft _iDerivation as follows:

The shear surface of supposing cross shaft is a cylinder, and the inner concrete of slip box forms a cylinder such as Fig. 9 in whipping process:

Then the shear rate of the viscosity resistance of A place generation is

$\frac{\mathrm{dv}}{\mathrm{dr}}=r\frac{\mathrm{d\ω}}{\mathrm{dr}}---\left(2\right)$

ω in the formula: the angular velocity of rotation variable at A place, v:A place linear velocity, r:A place radius is got

${\mathrm{\τ}}_{\mathrm{ji}}={\mathrm{\τ}}_0+{\mathrm{\η}}_p\frac{\mathrm{dv}}{\mathrm{dr}}---\left(3\right)$

Bring (1) formula, (2) formula into (3) formula, obtain after the arrangement:

$\mathrm{d\ω}=\frac{{2M}_{\mathrm{ji}}}{\mathrm{\π}{\mathrm{\η}}_p{r}^3(r+4h)}-\frac{{\mathrm{\τ}}_0}{{\mathrm{\η}}_p}\mathrm{dr}---\left(4\right)$

Work as r=R ₁The time, ω=0; Work as r=R ₂The time, ω=Ω.Substitution (4) formula is carried out integration:

$\underset{0}{\overset{\mathrm{\&Omega;}}{\&Integral;}}\mathrm{d\&omega;}=\underset{R_1}{\overset{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}{\&Integral;}}\frac{2M_{\mathrm{ji}}}{{\mathrm{\&pi;\&eta;}}_p({\mathrm{<figure-callout\; id="4"\; label="r"\; filenames="HA20186095200910027849701E00031.png"\; state="\{\{state\}\}">r</figure-callout>}}^4+4r^{3}h)}-\frac{{\mathrm{\&tau;}}_0}{{\mathrm{\&eta;}}_p}\mathrm{dr}---\left(5\right)$

$\mathrm{\&Omega;}=\frac{{2M}_{\mathrm{ji}}}{{\mathrm{\&pi;\&eta;}}_p}\left\{\frac{1}{{64\mathrm{<figure-callout\; id="3"\; label="h"\; filenames="HA20186095200910027849701E00022.png,HA20186095200910027849701E00031.png"\; state="\{\{state\}\}">h</figure-callout>}}^3}\ln \right[\frac{R_2(R_1+4h)}{R_1(R_2+4h)}]+\frac{(R_1-R_2)(R_1{R}_2-2h{R}_1-2h{R}_2)}{16h^2{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HA20186095200910027849701E00013.png"\; state="\{\{state\}\}">R</figure-callout>}}_1^2{R}_2^2}\}-\frac{{\mathrm{\&tau;}}_0}{{\mathrm{\&eta;}}_p}\ln \frac{R_2}{R_1}---\left(6\right)$

With (1) formula substitution (6) formula, transposition is put in order:

${\mathrm{\&tau;}}_{\mathrm{ji}}=\frac{{\mathrm{\&Omega;\&eta;}}_p+{\mathrm{\&tau;}}_0\ln \frac{R_2}{R_1}}{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2^2(R_2+4h)\left\{\frac{1}{{64\mathrm{<figure-callout\; id="3"\; label="h"\; filenames="HA20186095200910027849701E00022.png,HA20186095200910027849701E00031.png"\; state="\{\{state\}\}">h</figure-callout>}}^3}\ln \right[\frac{R_2(R_1+4h)}{R_1(R_2+4h)}]+\frac{(R_1-R_2)(R_1{R}_2-2h{R}_1-2h{R}_2)}{16h^2{R}_1^2{R}_2^2}\}}---\left(7\right)$

Because in (7) formula $\frac{\ln \frac{R_2}{R_1}}{R_2^2(R_2+4h)\left\{\frac{1}{64{\mathrm{<figure-callout\; id="3"\; label="h"\; filenames="HA20186095200910027849701E00022.png,HA20186095200910027849701E00031.png"\; state="\{\{state\}\}">h</figure-callout>}}^3}\ln \right[\frac{R_2(R_1+4h)}{R_1(R_2+4h)}]+\frac{(R_1-R_2)(R_1{R}_2-2h{R}_1-2h{R}_2)}{16h^2{R}_1^2{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2^2}\}}\&ap;1$

By shear rate

Can calculate:

${\mathrm{\&gamma;}}_i=\frac{\mathrm{\&Omega;}}{{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2^2(R_2+4h)\left\{\frac{1}{64{\mathrm{<figure-callout\; id="3"\; label="h"\; filenames="HA20186095200910027849701E00022.png,HA20186095200910027849701E00031.png"\; state="\{\{state\}\}">h</figure-callout>}}^3}\ln \right[\frac{R_2(R_1+4h)}{R_1(R_2+4h)}]+\frac{(R_1-R_2)(R_1{R}_2-2h{R}_1-2h{R}_2)}{16h^2{R}_1^2{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2^2}\}}---\left(8\right)$

Because $\mathrm{\&Omega;}=\frac{n_i\mathrm{\&pi;}}{30}---\left(9\right)$

Obtaining after (9) formula substitution (8)

${\mathrm{\&gamma;}}_i=\frac{n_i\mathrm{\&pi;}}{{30\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2^2(R_2+4h)\left\{\frac{1}{64{\mathrm{<figure-callout\; id="3"\; label="h"\; filenames="HA20186095200910027849701E00022.png,HA20186095200910027849701E00031.png"\; state="\{\{state\}\}">h</figure-callout>}}^3}\ln \right[\frac{R_2(R_1+4h)}{R_1(R_2+4h)}]+\frac{(R_1-R_2)(R_1{R}_2-2h{R}_1-2h{R}_2)}{16h^2{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="HA20186095200910027849701E00013.png"\; state="\{\{state\}\}">R</figure-callout>}}_1^2{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HA20186095200910027849701E00013.png,HA20186095200910027849701E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_2^2}\}}---\left(10\right)$

(10) formula is represented: shear rate can be by known quantity n _i, R ₁, h, R ₂Obtain.

In the formula: the diameter of the cross shaft of D-, n _i-Di i shelves rotating speed; R ₁-slip box height; H-rotating vane length; R ₂-rotating vane radius; ω-angular velocity, 0≤ω≤Ω.

J is organized sample i shelves rotation speed n _iThe τ that records down _JiThe data correspondence is averaged respectively, obtains i shelves shear rate γ _iWith average shear stress Relation is according to the shear rate γ that calculates _iWith average shear stress

Relation is drawn out concrete rheological curve figure, obtains a straight line by curve fitting

Obtain

τ wherein ₀For pouring into a mould preceding chutable concrete

Shear stress yield value under the condition, η _pFor

The plastic viscosity of slurry under the condition, thus can the concrete rheological of analyzing liquid; According to the different rotating speeds n that records _iUnder shear rate γ _iWith average shear stress Relation obtains the thixotroping hysteresis loop figure of chutable concrete, obtains two curvilinear function f up and down by curve fitting ₁(γ _i), f ₂(γ _i), integration gets concrete hysteresis loop area S again, thereby analyzes the concrete thixotropy of fluidised form, rheological and the thixotropy and the temperature parameter of the concrete sample that records some groups of using the same method.

Automatically gather the concrete mix sample from the stirring machine discharging opening, the temperature of the concrete mix sample that test record is gathered, and the rotation torque M under the different i shelves of each sample rotating speed _JiConcrete steps be: after the test beginning, magazine moves to stirring machine discharging opening below and accesses concrete mix sample to be measured, accesses to finish, and magazine retreats and leaves stirring machine discharging opening below, temperature sensor probe temperature T _jCross shaft in the magazine begins with different rotating speeds from low to high simultaneously, speed change from high to low stirs again, be divided into the i=11 shelves, velocity range is 60 commentaries on classics/min～200 commentaries on classics/min, rotated by 60 commentaries on classics/min～90 commentaries on classics/min-120 commentaries on classics/min～150 commentaries on classics/min-180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min-150 commentaries on classics/min～120 commentaries on classics/min-90 commentaries on classics/min～60 commentaries on classics/min, torque sensor is measured the rotary torque M under the different velocities of rotation simultaneously _Ji, to test the magazine gate that finishes and open, slurry flows out, once more sampling.

Having adopted a single-chip computer control system in the present invention, to realize automatic cycle testing, is to be MPU with single-chip microcomputer MSP430, mainly is divided into three parts.

The first, measure portion.The main amount of measuring has two, and the one, temperature T _j, purpose is the real time temperature of monitored concrete, the temperature T of during practical operation j being organized _jGetting arithmetic mean obtains Characterize the concrete temperature in a period of time, another is rotary torque M _Ji, purpose is to measure concrete rheological characteristics.These data that record all are stored on the single-chip microcomputer.

The second, control motor part.This part mainly is by the sampling of the advance and retreat of the magazine of Single-chip Controlling tester, has adopted that the speed change of cross shaft stirs and discharging behind the sample.Wherein the speed that stirs of speed change can stepping, such as being divided into 11 grades between 60～200～60 commentaries on classics/min.

The 3rd, communication part.This part is divided into man-machine interaction and computing machine communication two parts again.Wherein man-machine interaction comprises input media keyboard and output unit LCD LCD, can control the switch of whole tester, and with the temperature T that records _jWith rotary torque M _JiReal-time demonstration.The computing machine communication is that the data of will store are transferred to host computer by MAX232, by host computer data is carried out Treatment Analysis.

Beneficial effect:

1. this invention is for satisfying the engineering application request, utilization concrete rheological, Single-chip Controlling, Machine Design and control and database management language etc., the site operation rheological property of concrete online test method of developing, can obtain the rheological property of concrete on construction site parameter in time, conveniently, accurately, continuously, and concrete rheological is formed objective complete evaluation.

2. owing to adopt the flat cross shaft speed change that crouches to rotate, more meet the heterogeneous fluid that test contains thickness particles such as rubble, sand, the follow-on test concrete, can obtain a large amount of discrete sample datas, this method is applied to engineering practice, the defective of other method of testings of sum of errors sign property difference be can avoid artificially detecting, precision, robotization, informationization really realized.

3. based on Principle of Statistics, the test parameter result data is set up database, estimate rheological property of concrete according to analytical model.

Description of drawings

Fig. 1-W/B=0.40 chutable concrete

-γ _iCurve map.

Fig. 2-W/B=0.45 chutable concrete

-γ _iCurve map.

Fig. 3-W/B=0.40 concrete thixotroping hysteresis loop.

Fig. 4-W/B=0.45 concrete thixotroping hysteresis loop.

Fig. 5-tester schematic top plan view.

Fig. 6-tester groundwork part front view.

Fig. 7-tester groundwork part right view.

Fig. 8-cross shaft shear surface synoptic diagram.

Fig. 9-slurry motion state synoptic diagram when stirring test automatically.

Embodiment

Technical scheme of the present invention is: a kind of method for dynamically detecting rheological property of concrete on construction site, and step is:

At first, the Installation and Debugging tester when making the magazine of tester move to the sampling location, is sitting at stirring machine discharging opening below;

Then, begin sampling, gather the concrete mix sample automatically, the temperature T of the concrete mix sample that test is gathered from the stirring machine discharging opening _j, and i shelves different rotating speeds n _iUnder rotation torque M _Ji, the concrete mix sample number of j for needing altogether to test, i=1,2 ... 11, i be same sample by transformation of speed number of times between 60 commentaries on classics/min～200 commentaries on classics/min～60 commentaries on classics/min, continuous acquisition j sample in this way, temperature T _jGetting arithmetic mean is expressed as

Obtain one group of concrete mix j test sample

With the data storing of gathering in single-chip microcomputer MSP430.For guaranteeing the working-yard convenient test, in single-chip computer control system, be provided with automatic acquisition and memory system, can store 12 at most, 500 data, can obtain image data continuously, both can online on-line testing, also can be interrupted the read test data, thereby be convenient to the continuous working of Auto-Test System.Wherein, described different rotating speeds n _iBe meant between the rotating speed of 60 commentaries on classics/min～200 commentaries on classics/min, from low to high, the rotating speed that changes from high to low again is such as by 60 commentariess on classics/min～90 commentaries on classics/min-120 commentaries on classics/min～150 commentaries on classics/min-180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min-150 commentaries on classics/min～120 commentaries on classics/min-90 commentaries on classics/min～60 commentaries on classics/min rotation.

At last, the data transmission that stores in the single-chip microcomputer is carried out data analysis in host computer, according to gained rotary torque M _Ji, by formula

Calculate shear stress τ _Ji, in the formula: the diameter of the cross shaft of D-: h-rotating vane length: M _JiRotary torque during-Di j sample i shelves, π-3.14; According to rotation speed n _i, calculate shear rate γ by formula (10) _i, with same rotation speed n _iThe τ of the corresponding shelves of the j that records sample down _JiData are averaged, and obtain shear rate γ _iWith average shear stress

Relation is according to the shear rate γ that calculates _iWith average shear stress

Relation is drawn out concrete rheological curve figure, obtains a straight line by curve fitting

Obtain

τ wherein ₀For pouring into a mould preceding chutable concrete

Shear stress yield value under the condition, η _pFor

The plastic viscosity of slurry under the condition, thus can the concrete rheological of analyzing liquid; According to different rotating speeds n _iUnder shear rate γ _iWith average shear stress

Relation, the thixotroping hysteresis loop figure of acquisition chutable concrete obtains two curvilinear function f up and down by curve fitting ₁(γ _i), f ₂(γ _i), integration gets concrete hysteresis loop area S again, thereby analyzes the concrete thixotropy of fluidised form, rheological and the thixotropy and the temperature parameter of the concrete sample that records some groups of using the same method.

Automatically gather the concrete mix sample from the stirring machine discharging opening, the temperature T of the concrete mix sample that test is gathered _j, and same temperature T _jUnder, different rotating speeds n _iUnder rotation torque M _JiConcrete steps be: after the test beginning, magazine moves to stirring machine discharging opening below and accesses concrete mix sample to be measured, accesses to finish, and magazine retreats and leaves stirring machine discharging opening below, temperature sensor probe temperature T _jCross shaft in the magazine begins with different rotating speeds from low to high simultaneously, speed change from high to low stirs again, velocity range is 60 commentaries on classics/min～200 commentaries on classics/min, such as being rotated by 60 commentaries on classics/min～90 commentaries on classics/min-120 commentaries on classics/min～150 commentaries on classics/min-180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min-150 commentaries on classics/min～120 commentaries on classics/min-90 commentaries on classics/min～60 commentaries on classics/min, torque sensor is measured rotary torque M simultaneously _Ji, to test the magazine gate that finishes and open, slurry flows out, once more sampling.

Employed tester mainly opens and closes motor 7, pulley 8, travel switch (containing contact lever) 9, shaft coupling 10, relay 11, magazine scraper plate 12, MSP430 singlechip controller 13, cut-offing protecting switch 14,24V power supply 15, voltage stabilizer 16, regulator 17, temperature sensor 18, guide rail 19, guide wheel 20, rotating vane, turning axle, fixed screw, magazine 24 and filter screen 25 by torque sensor 1, stepper motor 2, orbit motor 3, transmission gear 4, tooth bar 5, cross shaft 6, magazine and forms shown in Fig. 5～7 among the present invention.A top of the trellis of tester is provided with a pair of guide rail that is parallel to each other 19, and guide rail 19 is provided with guide wheel 20, magazine 24 and magazine scraper plate 12, and travel switch 9 before and after also being provided with on guide rail 19 is with the extreme position of control magazine motion.Be parallel to guide rail and be provided with tooth bar 5 above guide rail, tooth bar 5 is connected with orbit motor 3 by transmission gear 4.Magazine 24 is provided with filter screen 25, be provided with the flat cross shaft 6 that crouches in the magazine 24, the flat cross shaft 6 that crouches is connected with stepper motor 2 by shaft coupling 10, on shaft coupling, be provided with torque sensor 1, also be provided with temperature sensor 18 on magazine 24, magazine 24 opens and closes motor 7 by pulley 8 and magazine and is connected the knife switch discharging that is used for controlling magazine 24 bottoms.The flat cross shaft 6 that crouches is made up of turning axle 22, rotating vane, and rotating vane is fixed on the turning axle by fixed screw.Magazine 24 can slide along guide rail 19 under the drive of orbit motor 3 by transmission gear 4, tooth bar 5.In order to guarantee the normal operation of whole device, on tester bracket, also be provided with relay 11, MSP430 singlechip controller 13, cut-offing protecting switch 14, power supply 15, voltage stabilizer 16, regulator 17.

Test job begins, start start button, pilot lamp is bright, magazine 24 is by transmission gear 4, tooth bar 5 advances under the drive of orbit motor 3, discharging opening place during to guide rail 19 tops, touch travel switch 9, halt and begin to connect material, chutable concrete enters magazine 24 by filter screen 25 elimination super-size aggregates, magazine 24 stops to retreat behind the 20s, unnecessary concrete scrapes off by magazine scraper plate 12 on the filter screen 25, after touching travel switch 9, stop to retreat, measure the concrete temperature index by the temperature sensor of settling in the magazine 24 18, simultaneously, cross shaft 6 is rotated by 60 commentaries on classics/min～90 commentaries on classics/min-120 commentaries on classics/min～150 commentaries on classics/min-180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min-150 commentaries on classics/min～120 commentaries on classics/min-90 commentaries on classics/min～60 commentaries on classics/min under stepper motor 2 drives, rotating required driving torque is measured by torque sensor 1, represent with voltage, demonstration also is stored on the MSP430 singlechip controller 13, test finishes, magazine opens and closes motor 7 and opens, the gate of magazine bottom is opened, slurry flows out, discharge process continues about 10s, magazine opens and closes motor 7 and closes, the magazine bottom gate closes behind the time-delay 7s, a loop ends and then enter circulation next time behind the time-delay 5s.

Embodiment 1

Application example: test j=1,2 ... 5 each one group of the rheological parameter under two kinds of different mixture ratio of totally 5 samples and the area between the thixotroping hysteresis loop, match ratio such as following table:

Table 1 concrete mix

1. test torque value and corresponding rotating speed such as the following table obtained:

The moment of torsion of the corresponding rotating speed of table 2W/C=0.40 chutable concrete

The moment of torsion of the corresponding rotating speed of table 3W/C=0.45 chutable concrete

According to rotation speed n _i, can calculate shear rate γ by formula (9) _i, can calculate corresponding shear stress τ automatically by formula (1) according to the gained rotary torque _Ji

Five groups of τ that calculate by data based formula (1) and (9) of table 2 and table 3 _JiData are asked on average, get shear rate γ _iWith average shear stress

Relation is as table 4, table 5.

Table 4 calculates and obtains W/C=0.40 shear rate γ _iAnd shear stress

Relation

Table 5 calculates and obtains W/C=0.45 shear rate γ _iAnd shear stress

Relation

According to table 4 and table 5 each 11 groups preceding 5 groups average The result obtains concrete rheological curve, as shown in Figure 1 and Figure 2,

By Fig. 1,2 and table 4,5 can get: the fitting function of rheological curve is respectively:

τ _0.4＝25.65γ _0.4+201.6，τ _0.45＝20.386γ _0.45+194.02

R wherein ²Be respectively 0.9661 and 0.9536;

According to rheological formula rheological parameter such as following table as can be known

As seen from the above table, water cement ratio W/C increases, concrete mix viscosity coefficient η _pObviously reduce, and initial yield stress τ ₀Change less.

2. according to each 11 groups average of table 4 and table 5

The result obtains concrete thixotroping hysteresis loop such as Fig. 3, Fig. 4;

As seen, the thixotroping hysteresis loop is by lower curve f ₁(γ _i) and upper curve f ₂(γ _i) form, and two curves do not overlap, and this explanation sample exists thixotropy, and concrete mix is sheared desaturation, and thixotropic big I is characterized by the area between two curves, and as above figure is by formula

$S={\&Integral;}_{{\mathrm{\&gamma;}}_1}^{{\mathrm{\&gamma;}}_6}[f_2\left({\mathrm{\&gamma;}}_i\right)-f_1\left({\mathrm{\&gamma;}}_i\right)]\mathrm{d\&gamma;}$

The area that can calculate between the thixotroping hysteresis loop is as follows:

S _0.40＝35340，S _0.45＝22942

Along with water cement ratio W/C increases, the thixotroping hysteresis area of concrete mix reduces, and thixotropy has the trend that reduces gradually.

In this example just for the example of a simplification come method of the present invention is described, just changed water cement ratio in this example, under a water cement ratio, only got one Can get some groups in the practical operation according to actual needs

Obtain some groups accordingly

Make up database to analyze the concrete rheological implementations of working-yard.

Claims (3)

1. a method for dynamically detecting rheological property of concrete on construction site is characterized in that, step is:

At first, the Installation and Debugging tester when making the magazine of tester move to the sampling location, is positioned at the discharge port below of concrete placement vehicle or pump;

Then, begin sampling, gather the mixture sample automatically from the pouring out concrete mouth, the temperature T of concrete mix sample is gathered in test _j, the T to gathering then _jGet arithmetic mean, obtain the temperature of this group

J=1 wherein, 2 ... k, j represent the specimen coding of the same batch of required test of concrete, and k is the sample sum of the same batch of required test of concrete, and k is according to concrete needs value; Each sample different rotating speeds n under the follow-on test j sample _iUnder rotation torque M _Ji, j=1 wherein, 2 ... k, j, k meaning are the same, i=1,2 ... 11, i is that same sample is by transformation of speed number of times between 60 commentaries on classics/min～200 commentaries on classics/min～60 commentaries on classics/min; In this way continuous acquisition obtains the { M of same batch of concrete mix sample _Ji, n _i,

Some groups, with the data storing of gathering in single-chip microcomputer;

At last, the data transmission that stores in the single-chip microcomputer is carried out data analysis in host computer, according to gained rotary torque M _Ji, by formula

Calculate shear stress τ _Ji, in the formula: the diameter of the cross shaft of D-: h-rotating vane length: M _JiRotary torque during-Di j sample i shelves, π-3.14; According to rotation speed n _i, by formula:

Calculate shear rate γ _i, R wherein ₁-slip box height, R ₂-rotating vane radius, h-rotating vane length, n _i-Di i shelves rotating speed; With i shelves rotation speed n corresponding in j the sample _iCalculate the τ of gained down _JiData are averaged respectively, obtain shear rate γ _iWith average shear stress

Relation is according to i shelves shear rate γ _iWith average shear stress

Relation is drawn out concrete rheological curve figure, obtains a straight line by curve fitting Obtain

τ wherein ₀For pouring into a mould preceding chutable concrete

Shear stress yield value under the condition, η _pFor The plastic viscosity of slurry under the condition is in order to the concrete rheological of analyzing liquid; According to the shear rate γ under j the sample i shelves rotating speed that obtains _iWith average shear stress

Relation is drawn the thixotroping hysteresis loop figure of chutable concrete, obtains two curvilinear function f up and down by curve fitting ₁(γ _i), f ₂(γ _i), integration gets concrete hysteresis loop area S again, in order to analyze the concrete thixotropy of fluidised form, to use the same method rheological and the thixotropy and the temperature parameter of the concrete sample that records some groups.

2. method for dynamically detecting rheological property of concrete on construction site as claimed in claim 1 is characterized in that, described different rotating speeds n _iBe meant from 60 commentaries on classics/min～90 commentaries on classics/min-120 commentaries on classics/min～150 commentaries on classics/min-180 commentaries on classics/min～200 commentaries on classics/min～180 commentaries on classics/min-150 commentaries on classics/min～120 commentaries on classics/min-90 commentaries on classics/min～60 commentaries on classics/min and rotate.

3. method for dynamically detecting rheological property of concrete on construction site as claimed in claim 1 is characterized in that, gathers the concrete mix sample automatically from the stirring machine discharging opening, the temperature of the concrete mix sample that test is gathered, and different rotating speeds n _iUnder rotation torque M _JiConcrete steps be: after the test beginning, magazine moves to stirring machine discharging opening below and accesses concrete mix sample to be measured, access and finish, magazine retreats and leaves stirring machine discharging opening below, the temperature sensor probe temperature, the cross shaft in the magazine begins with different rotating speeds from low to high simultaneously, and speed change from high to low stirs again, velocity range is 60 commentaries on classics/min～200 commentaries on classics/min, and torque sensor is measured rotary torque M simultaneously _Ji, to test the magazine gate that finishes and open, slurry flows out, once more sampling.

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