JP2003177087A - Method for estimating deterioration in strength of alc panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an estimation method of strength deterioration in an ALC panel that can easily and rapidly estimate the degree of strength deterioration due to carbonation at a building field and can reduce a load to a building as much as possible. <P>SOLUTION: A power driver that can measure torque and a tool for measuring torque having a mechanism for racing a screw nut are used. The screw nut is set while the tool for measuring torque is installed on the surface of the ALC panel. The screw nut is screwed by the driver. The maximum torque value immediately before the screw nut races is measured. The degree of strength deterioration due to the carbonation of the ALC panel is estimated according to the maximum torque value and the degree of carbonation. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a degree of deterioration of strength due to carbonation of ALC panels (lightweight cellular concrete panels) used for walls, roofs, floors and the like of buildings. (durability)
And a method for estimating. 2. Description of the Related Art An ALC panel is mainly composed of a siliceous raw material such as silica stone and a calcareous raw material such as cement and quick lime, and water, aluminum powder and other additives are added to these fine powders to form a slurry. After that, it is poured into the formwork in which the reinforcing steel bars are arranged, and fired by the reaction of the aluminum powder,
It is semi-cured by the reaction of calcareous raw materials, formed into a predetermined size, and then subjected to high-temperature and high-pressure steam curing using an autoclave. This ALC panel is widely used as a building material because it is lightweight with an absolute dryness specific gravity of about 0.5, and has excellent durability, heat insulation properties, and workability. [0003] The durability of the ALC panel is judged to have deteriorated due to the occurrence of cracks and a decrease in panel strength.
Factors that deteriorate the durability of the ALC panel are roughly classified into external factors and internal factors. Among these factors, internal factors include frost damage, salt damage, carbonation, drying shrinkage, and the like. Among these internal factors, carbonation is a reaction in which tobermorite, a main mineral of ALC, is decomposed into silica gel and calcium carbonate in an environment where carbon dioxide gas and moisture are present. It is known that even when applied to a subject, it gradually progresses. In addition, the carbonation causes the ALC panel to contract (carbonation contraction), and the carbonized ALC panel increases in dry shrinkage, leading to cracks and reduced panel strength due to repeated drying shrinkage and wet expansion. It is concerned. Conventionally, as a method of estimating the degree of deterioration of an ALC panel due to carbonation, a method of measuring the calcium oxide content and the carbon dioxide gas content of an ALC panel and estimating the degree of deterioration based on the measured values is known. (Japanese Patent Laid-Open 2000
-180437). This method performs a chemical analysis to measure the total calcium oxide content in order to determine the total calcium content of the ALC panel, and the carbon dioxide gas content in order to determine the calcium carbonate content in the ALC panel. A thermal analysis for measurement was performed,
/ 44) / (total calcium oxide content) × 100 is a method of calculating the degree of carbonation and estimating the degree of deterioration from the value. Here, the chemical analysis is performed, for example, by ICP-AES.
(Inductively coupled plasma atomic spectroscopy) and thermal analysis
For example, DTA-TG (thermal analysis using a differential thermal balance) is performed. Further, as a method of estimating the degree of deterioration of the ALC panel from the panel strength, a method of measuring physical properties such as compressive strength by cutting out a block block from the panel itself, or a method of removing the panel itself and performing a direct bending test or the like. There is a method of estimating the degree of deterioration based on a value obtained by a method of measuring bending strength by a test. [0006] However, the above-mentioned conventional method for estimating the degree of deterioration of the ALC panel has the following problems. The method of measuring the degree of carbonation of the panel by ICP-AES (inductively coupled plasma atomic spectroscopy), DTA-TG (thermal analysis using a differential thermal balance), or the like, and estimating the degree of deterioration based on the measured value is described in Panel Has the disadvantage that it takes a relatively long time to measure the degree of carbonation. Also, methods such as cutting out a block block from a panel and measuring physical properties such as strength, and removing the panel itself from a building and measuring bending strength are all large-scale methods. There is a problem that not only is time and labor required, but also a great burden is imposed on the building owner. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to easily and quickly estimate the degree of strength deterioration due to carbonation at a building site, and to reduce the burden on the building owner. It is an object of the present invention to propose a method of estimating the strength deterioration of an ALC panel which can reduce the intensity as much as possible. The present inventors have made various studies to solve the above-mentioned conventional problems, and as a result, have found that the degree of carbonation and compressive strength of the ALC panel of an existing building and the screw strength have been improved. We found that there was a strong correlation between the maximum tightening torque of the screws, and for existing building ALC panels,
Only by measuring the tightening torque when attaching a screw screw having a diameter of about 4 to 7 mm, the degree of deterioration in strength due to carbonation can be easily estimated, and after the measurement, the screw screw is removed and a hole having a diameter of about 4 to 7 mm is removed. A: The existing building is hardly surveyed by repairing.
A method for estimating the degree of strength deterioration due to carbonation of an LC panel was found. That is, the method for estimating the degree of deterioration of an ALC panel according to the present invention includes an electric or air-driven driver capable of measuring torque, a lower housing and an upper housing having through holes that can pass through screw screws on the same axis. Using a torque measuring jig having a trumpet-shaped recess for receiving the head of a screw screw at the opening of the through hole of the upper housing, and using a torque measuring jig, In the state where the torque measuring jig is installed, a screw screw is set in the through hole of the jig, the screw screw is screwed with the screwdriver, and the maximum torque value immediately before the screw screw idles is measured, ALC from its maximum torque value and degree of carbonation
It is characterized by estimating the degree of strength deterioration due to carbonation of the panel. The screw in the present invention is not particularly limited, but a screw having a diameter of about 4 to 7 mm is suitable. An existing electric or pneumatic driver capable of measuring torque can be used. For example, a driver in which an output device (recording device) is connected to an electric or air-driven driver is used. The jig for torque measurement has a mechanism to idle the screw screw,
In addition, the torque can be measured while holding the screw at right angles to the surface of the ALC panel, and the screw can be removed vertically and easily after the measurement without increasing the screw hole. More specifically, the lower and upper housings are rotatably integrated with each other via a bearing. Even if the screw is loosely screwed into the upper and lower housings by the screwdriver, the screw further rotates. (I.e., idle) so that the maximum torque value immediately before the screw screw idles can be measured. In the present invention, the degree of strength deterioration due to carbonation of the ALC panel is estimated from the maximum torque value and the degree of carbonation of the ALC panel previously calculated by the above-described known method. The degree of carbonation of the ALC panel is determined by the above-mentioned ICP-AES (inductively coupled plasma atomic spectroscopy),
It can be measured by DTA-TG (thermal analysis using a differential thermal balance). That is, in order to determine the total calcium content of the ALC panel, the total calcium oxide content was measured by ICP-AES, and in order to quantify the calcium carbonate content of the ALC panel, the carbon dioxide content was measured by DTA-TG. The amount was measured and (carbon dioxide content x 56
/ 44) / (total calcium oxide content) × 100 to calculate the degree of carbonation. FIG. 1 is a schematic view showing the structure of an apparatus for carrying out a method for estimating the strength deterioration of an ALC panel according to the present invention. FIG. 2 is an enlarged view of a torque measuring jig of the same apparatus. 1 is a schematic longitudinal sectional view showing an ALC panel, 11 a torque measuring jig, 13 a power driver, 14 an output device, and 15 a screw screw. That is, the apparatus for carrying out the method of the present invention comprises a torque measuring jig 12 for holding a screw screw 15 on an ALC panel 11 and causing the screw screw 15 to spin, and a screw screw 15 held by the torque measuring jig. And an output device 14 for measuring the maximum torque value immediately before the screw screw 15 fastened to the ALC panel 11 idles. You. As shown in FIG. 2 in an enlarged manner, the torque measuring jig 12 has a through hole 12-1a at the center thereof through which the screw screw 15 can be slowly penetrated, and a trumpet-shaped recess 12- which receives the head 15-1 of the screw screw 15. 1b, and a lower housing 1 having a through hole 12-2a through which the screw screw 15 can be slowly penetrated on the same center line as the through hole 12-1a.
2-2 are rotatably overlapped with each other via a bearing 12-3, and are integrated, and loosely penetrate through the through holes 12-1a and 12-2a of the upper housing 12-1 and the lower housing 12-2. Even if the screw screw 15 is tightened by the driver 13, the screw screw can be further rotated (idle). When estimating the deterioration of the strength of the ALC panel by the apparatus having the above structure, the torque measuring jig 12 is installed on the surface of the ALC panel 11 and the through holes 12-1a, 12-2a with screw screw 15
And screw the screw 15 to the screwdriver 1
Screw in 3. The torque value at this time is
Is recorded by the output device 14 connected to the. The output device 14 measures the maximum torque value immediately before the screw screw 15 idles, and estimates the degree of strength deterioration due to carbonation of the ALC panel 11 from the maximum torque value and a previously determined degree of carbonation. FIG. 3 shows the relationship between the maximum torque value of the ALC panel of the actual building and the degree of carbonation obtained by using the above apparatus. The screw used is about 4m in diameter
m, an electric driver 13 was used. The degree of carbonation is determined by the above-mentioned ICP-AES (inductively coupled plasma atomic spectroscopy) and DTA-TG (thermal analysis using a differential thermobalance).
Was measured by After the measurement, the screw was removed, and a hole having a diameter of about 4 mm was repaired. As is clear from the data shown in FIG. 3, the degree of strength deterioration due to carbonation of the ALC panel can be estimated from the maximum tightening torque of the screw. As described above, according to the method of the present invention, the measurement of the maximum tightening torque when screwing a screw having a diameter of about 4 to 7 mm into the ALC panel is performed only by measuring the maximum tightening torque. Since the degree of strength deterioration due to carbonation can be estimated, the degree of strength deterioration due to carbonation can be easily and quickly estimated at the building site, and after measurement, screw screws are removed and the screw holes are simply repaired Therefore, it is possible to estimate the degree of strength deterioration of the existing building due to carbonation of the ALC panel with almost no load on the existing building.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an apparatus configuration for implementing a method for estimating the strength deterioration of an ALC panel according to the present invention. FIG. 2 is a schematic longitudinal sectional view showing a torque measuring jig of the above device in an enlarged manner. FIG. 3 is a diagram showing a relationship between a maximum torque value of an ALC panel of an actual building and a degree of carbonation obtained by the method of the present invention. [Description of Signs] 11 ALC panel 12 Jig for torque measurement 12-1 Upper housing 12-2 Lower housing 12-1a, 12-2a Through-hole 12-1b Trunk-shaped recess 13 Driver 14 Output device 15 Screw screw

Claims (1)

Claims 1. An electric or pneumatic driver capable of measuring torque and a lower housing and an upper housing having through holes through which a screw screw can be slowly penetrated on the same axis via a bearing. The torque measurement jig is provided on the ALC panel surface by using a torque measurement jig having a trumpet-shaped recess for receiving the head of a screw screw at the opening of the through hole of the upper housing and integrally provided so as to be mutually rotatable. In the state where the jig is installed, a screw screw is set in the through hole of the jig, the screw screw is screwed in with the screwdriver, the maximum torque value immediately before the screw screw idles is measured, and the maximum torque value is measured. A method for estimating the degree of strength deterioration of the ALC panel due to carbonation from the carbonation degree and the degree of carbonation.