Early-warning system and method for temperature cracks on surface of concrete

A technology for concrete surface and temperature cracks, applied in directions such as thermometers that give differential values, can solve problems such as temperature gradients and easy surface cracks

Active Publication Date: 2012-03-28
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide a concrete surface temperature crack early warning system and method for the problem that the surface concrete temperature gradient is too large and easy to crack, which can remind construction to take insulation measures under severe conditions and reduce the probability of surface cracks

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  • Early-warning system and method for temperature cracks on surface of concrete
  • Early-warning system and method for temperature cracks on surface of concrete
  • Early-warning system and method for temperature cracks on surface of concrete

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Embodiment approach

[0033] figure 2 A hardware block diagram of an early warning system for concrete surface cracks. The early warning system of the present invention includes a temperature sensor 2, a data processing unit and an alarm, and the data processing unit includes an amplifier, an analog signal conversion circuit, a display, a power supply circuit and a single-chip microcomputer including a calculation program; the temperature data collected by the temperature sensor 2 is processed by the amplifier. 1. After the analog signal conversion circuit, it is input into the single-chip microcomputer; after the single-chip computer performs the calculation, the calculation result is displayed on the display, and when the calculation result is greater than the alarm threshold, it outputs a signal to the alarm to alarm.

[0034] Three or more temperature sensors 2 (such as figure 1 shown), the connection of the temperature sensor 2 is connected to the computing equipment, and the computing equip...

Embodiment

[0078] In this implementation, a total of three common temperature sensors 2 (but not limited to three temperature sensors) are used, the measurement accuracy of the temperature sensors 2 are all ±0.3°C, and the time interval for the temperature sensors 2 to collect temperature data is 1 second. The three temperature sensors are first fixed in the mortar prefabricated parts, and the prefabricated parts are embedded in the concrete silo, and the size of the concrete silo is 20m×60m×3m. The actual buried depths of the three temperature sensors 2 in the concrete silo are 0.05m, 0.10m, and 0.15m, respectively.

[0079] Actual concrete ultimate tensile stress standard σ t =1.0MPa, take the concrete surface as the alarm judgment position P. The concrete parameters are λ=141.1524kJ / (md°C), E=3.54e10Pa, μ=0.18, φ(ε)=1.0, β=800kJ / (dm 2 °C), a=0.0022m 2 / h (where E is the elastic modulus of the concrete, μ is the Poisson’s ratio, α is the coefficient of linear expansion, T 0 is th...

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Abstract

The invention provides an early-warning system and method for temperature cracks on a surface of concrete and relates to a method for measuring and calculating the temperature gradient of concrete and alarming for a dangerous working condition. For the invention, an alarm judging position and the temperature gradient threshold of the position are preset according to the actual engineering need and the concrete properties; a temperature sensor, a data processing unit and an alarm which are ordinary are used; the temperature gradients of all points are calculated according to the formula by measuring the temperature of the concrete in the range 0.5m from the surface of the concrete; and the alarm gives an alarm when the temperature gradient at the judging position is more than the preset threshold. The early-warning system has the characteristics of timely and accurate alarming and simplicity and convenience in operation, and has obvious effect in the aspects of preventing the temperature cracks on the surface of the large-volume concrete.

Description

technical field [0001] The invention relates to an early warning system and method for concrete surface cracks, in particular to a method and equipment for automatic monitoring of concrete surface cracks during large-volume concrete construction. Background technique [0002] Surface cracks in concrete are a very common phenomenon in concrete structures, especially during construction and operation, the generation of surface cracks is mainly affected by changes in ambient temperature. During cold waves and wintering, sudden temperature drops often cause excessive temperature gradients on the concrete surface, resulting in surface temperature cracks. At present, most of the early warning systems and methods for surface temperature cracks of mass concrete are based on engineering experience, and the timing of taking thermal insulation measures is judged according to the temperature measurement data. There is no method for automatically measuring temperature and alarming for su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01K3/14
Inventor 胡昱李庆斌林鹏张丽媛韦宇硕
Owner TSINGHUA UNIV
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