CN102495108A - Method for monitoring water content change in concrete in situ - Google Patents

Abstract

The invention discloses a method for monitoring the water content change in concrete in situ, comprising the following steps: first, directly burying a water content change monitoring sensor in a position to be monitored in the concrete, then transmitting the cork impedance values obtained by the water content change monitoring sensor to a monitoring center to process, calculating the water content in the sensor, and then further inferring the water content change in the monitored concrete. According to the invention, the in situ real-time measurement of the water content change in the concrete can be realized without stable time, wherein the sampling period can be less than 1 ms, and the water content monitoring scope is 0-100 %.

Description

The method of change of moisture content in a kind of in-situ monitoring concrete

Technical field

The present invention relates to concrete non-destructive monitoring technical field, be specifically related to the method for change of moisture content in a kind of in-situ monitoring concrete.

Background technology

Water cut in the in-situ monitoring concrete is extremely difficult.Though the technology of humidity in existing at present many measurement porosints; But can be used for concrete does not see from the original position water cut monitoring technology that is poured into long-age as yet; Because: (1) does not still have the sensor that can directly imbed fresh concrete at present; Because of many jellies, polyion, humidity in the fresh concrete are 100%, most electrical measurement class sensors are being imbedded the i.e. inefficacy rapidly in back; Usually need one when (2) relative humidity sensor is measured and measure cavity to satisfy the needs of VLE measuring principle, so can't directly contact detected concrete; (3) measuring techniques such as neutron, microwave, optical fiber, TDR, FDR, apparatus expensive, the monitoring on a large scale of uncomfortable large scale structure.

The Viggo Jensen of Norway utilizes a kind of back dress to draw quick (Ramin) wooden stick to come the relative humidity in the discontinuous measurement maturing as sensor; This sensor constitutes with the plastic tube in two holes and the quick wooden stick that draws of two sections by one, and every section wooden stick is a sensor.Its measuring principle is: form VLE at the plastic tube tapping, through the wooden stick electricity that calibrates in advance lead and relative air humidity between the relation curve institute that converts survey regional relative humidity.Obviously, this sensor only is applicable to maturing.Through the back dress, be interrupted to extract out to measure and draw the electricity of quick wooden stick to lead.The characteristic of this sensor Yin Lamin wood is particularly suitable for the measurement of RH80～95%, and this also is the indeterminable zones of many commercial humidity sensors.Show that this humidity sensor has good long term stability although the entity structure that reaches 7 years is used, it still has following shortcoming: (1) ex situ is directly measured; (2) measurement is long required stabilization time, is generally 1～12hrs; (3) measurement range is limited; (4) only can be used for maturing.

Summary of the invention

In order to overcome the shortcoming of above-mentioned prior art, the present invention provides the method for change of moisture content in a kind of in-situ monitoring concrete, can be in real time, the in-situ monitoring concrete makes a fresh start and mix the change of moisture content in the concrete to the long-age.

For achieving the above object, the technical scheme that the present invention takes is:

The method of change of moisture content in a kind of in-situ monitoring concrete may further comprise the steps:

The first step, position to be monitored in concrete is directly buried change of moisture content monitoring sensor in the concrete underground;

In second step, the cork resistance value that the change of moisture content monitoring sensor is measured is transferred to monitoring center and handles;

The 3rd step, by demarcating good cork impedance and the water cut in its water cut funtcional relationship calculating sensor, or by the cork bone dry of measuring with the resistance value when satisfying water fully, through following linear difference formula, the water cut in the calculating sensor:

$W=\frac{R}{(R_0-R_{100})}\×100\%$

In the formula: W is a relative water content, and R is the cork resistance value that monitors, R ₀Resistance value during for the cork bone dry, R ₁₀₀Resistance value when satisfying water fully, and then the variation of knowing the water cut in the concrete of monitoring by inference for cork.

The present invention can realize that the original position of change of moisture content is measured in real time in the concrete, need not stabilization time, the sampling period can＜1ms, the water cut monitoring range is 0～100%.

Description of drawings

Fig. 1 is that the present invention monitors change of moisture content principle schematic in the concrete.

Fig. 2 is the Monitoring Data figure in the embodiment of the invention tidal range district concrete sample.

Fig. 3 is that embodiment of the invention wave spatters the Monitoring Data figure in district's concrete sample.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is done detailed description.

With reference to Fig. 1, the method for change of moisture content in a kind of in-situ monitoring concrete may further comprise the steps:

The first step, position to be monitored in concrete T is directly buried change of moisture content monitoring sensor P in the concrete underground;

In second step, change of moisture content monitoring sensor P is transferred to monitoring center through electrode K and the measured cork m resistance value of lead L handles;

The 3rd step, by demarcating good cork impedance and the water cut in its water cut funtcional relationship calculating sensor, or by the cork bone dry of measuring with the resistance value when satisfying water fully, through following linear difference formula, the water cut in the calculating sensor:

$W=\frac{R}{(R_0-R_{100})}\×100\%$

In the formula: W is a relative water content, and R is the cork resistance value that monitors, R ₀Resistance value during for the cork bone dry, R ₁₀₀Resistance value when satisfying water fully, and then the variation of knowing the water cut in the concrete of monitoring by inference for cork.

Embodiment one

The method of change of moisture content in a kind of in-situ monitoring concrete may further comprise the steps:

The first step, one be arranged in marine tidal range district the C35 concrete sample, by shown in Figure 1; In burying a change of moisture content monitoring sensor respectively underground from concrete surface 5mm depths, wherein the diameter of cork is 6mm, and length is 3mm; A pair of gold-plated electrode, diameter are 0.15mm, and length is 2.5mm; Electrode separation is 2.5mm, and sheath is that thickness is that 2.5mm, diameter are that 25mm, length are the PP plastic tube of 40mm;

In second step, the cork resistance value that the change of moisture content monitoring sensor is measured is transferred to monitoring center and handles;

The 3rd step, the resistance value during by cork bone dry of measuring and full fully water, through following linear difference formula, the water cut in the direct calculating sensor:

$W=\frac{R}{(R_0-R_{100})}\×100\%$

In the formula: W is a relative water content, and R is the cork resistance value that monitors, R ₀Resistance value during for the cork bone dry, R ₁₀₀Resistance value when satisfying water fully for cork,

Monitoring sampling period＜1ms, monitoring is spaced apart 5min.

Fig. 2 is the part Monitoring Data in the tidal range district concrete sample, can find out, receives the tidal range effect; The water cut at concrete surface layer place is 98.5～99.5% variations; The water sorption of this and concrete surface layer mortar is closely related, fits like a glove with actual conditions, it can also be seen that simultaneously; The used sensor response of the present invention is fast, is suitable for the on-site real-time monitoring.

Embodiment two

Press embodiment one described same steps as; Be arranged in the identical monitoring of concrete sample enforcement that wave spatters district C40 one, Fig. 3 is the part Monitoring Data, can find out; The water cut at concrete surface layer place is in drying regime basically; Receive wave to spatter effect, can in 0～0.9%, change once in a while, this conforms to actual conditions fully.

Claims (1)

1. the method for change of moisture content in the in-situ monitoring concrete is characterized in that, may further comprise the steps:

The first step, position to be monitored in concrete is directly buried change of moisture content monitoring sensor in the concrete underground;

In second step, the cork resistance value that the change of moisture content monitoring sensor is measured is transferred to monitoring center and handles;

The 3rd step, by demarcating good cork impedance and the water cut in its water cut funtcional relationship calculating sensor, or by the cork bone dry of measuring with the resistance value when satisfying water fully, through following linear difference formula, the water cut in the calculating sensor:

$W=\frac{R}{(R_0-R_{100})}\×100\%$

In the formula: W is a relative water content, and R is the cork resistance value that monitors, R ₀Resistance value during for the cork bone dry, R ₁₀₀Resistance value when satisfying water fully, and then the variation of knowing the water cut in the concrete of monitoring by inference for cork.

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