Method for testing expansion/contraction stress of cement-based material
What is Al technical title?
Al technical title is built by PatSnap Al team. It summarizes the technical point description of the patent document.
A cement-based material, shrinkage stress technology, applied in material inspection products, electrical/magnetic solid deformation measurement, electromagnetic measurement devices, etc.
Active Publication Date: 2010-07-07
JIANGSU SOBUTE NEW MATERIALS
View PDF2 Cites 27 Cited by
Summary
Abstract
Description
Claims
Application Information
AI Technical Summary
This helps you quickly interpret patents by identifying the three key elements:
Problems solved by technology
Method used
Benefits of technology
Problems solved by technology
[0015] Using this method can easily calculate the shrinkage and expansion stress of cement concrete under restricted conditions, but since the restraint is mainly provided by the steel bars in the middle, the degree of restraint is mainly determined by the size of the middle steel bars, the degree of restraint is not large enough, and the middle and There are stress concentrations at both ends
In addition, this
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more
Image
Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
Click on the blue label to locate the original text in one second.
Reading with bidirectional positioning of images and text.
Smart Image
Examples
Experimental program
Comparison scheme
Effect test
Embodiment 1
[0072] 1: Basic parameters of the test
[0073] The ring material is low carbon steel, the modulus of elasticity is 206GPa, and Poisson's ratio is 0.3.
[0074] Ring size is R 1 =52mm,R 2 =60mm,R 3 =85mm,R 4 =95mm, h=t=25mm.
[0075] The test proportion (clean pulp) is as follows:
[0076] Table 2 test mix ratio (kg / m 3 )
[0077]
[0078] In Table 2, KB is the benchmark specimen (elastic modulus 20GPa, Poisson’s ratio 0.2), PZJ is the specimen mixed with expansion agent (elastic modulus 18GPa, Poisson’s ratio 0.2), the test environment conditions are 20°C, 60% relative humidity.
[0079] 2: Test results and analysis
[0080] Figure 4 It is the steel ring strain of C50-KB group. For the net slurry KB, the outer ring is not subject to external force, which is basically 0, and the inner ring is under pressure, so it is a negative strain. At 4.2 days, the strain of the inner ring changes abruptly, which characterizes the first cracking time of the specimen.
[00...
Embodiment 2
[0087] 1: Basic parameters of the test
[0088] The ring material is Invar steel, with an elastic modulus of 160GPa and a Poisson's ratio of 0.3.
[0089] Ring size is R 1 = 100mm, R 2 =115mm, R 3 =145mm, R 4 =160mm, h=t=75mm.
[0090] The concrete test ratio is as follows (aggregate particle size 5mm-10mm):
[0091] Table 4 Example 2 concrete mix ratio (kg / m 3 )
[0092]
[0093]In Table 4, KB is the benchmark concrete specimen (elastic modulus 30GPa, Poisson’s ratio 0.2), PZJ is the concrete specimen mixed with expansion agent (elastic modulus 28GPa, Poisson’s ratio 0.2), and the test environment conditions are 20°C, 35 % relative humidity, the surface is covered with ethylene plastic film for 2.5 days of moisture-proof curing, and then dried at 35% relative humidity.
[0094] Figure 7 is the steel ring strain of concrete KB group. Within 2.5 days, the strain of the inner ring and the outer ring is basically 0, that is, the concrete has not deformed significant...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more
PUM
Property
Measurement
Unit
Height
aaaaa
aaaaa
Elastic modulus
aaaaa
aaaaa
Elastic modulus
aaaaa
aaaaa
Login to view more
Abstract
The invention relates to a method for testing expansion/contraction stress of a cement-based material, which adopts a device for testing the expansion/contraction stress of the cement-based material is adopted. The device comprises inner and outer circular rings which are coaxially arranged and have the same height, and a strain testing device and a data acquisition device which are mutually electrically connected, wherein the materials of the inner and the outer circular rings are the same; the strain testing device comprises a plurality of testing strain gauges; the strain gauges are distributed on the external surface of the outer circular ring and the internal surface of the inner circular ring uniformly along a circumferential direction, and each testing strain gauge is electrically connected with the data acquisition device; the cement-based material is poured between the inner and the outer circular rings, and the strain of the inner and the outer circular rings is tested; and the expansion/contraction stress at a position where the internal radius of the cement-based material is r is calculated according to a formula (I). The method has the advantages that a, the test device is simple, and the operation is simple and convenient; b, restraint stress is uniform; and c, the method can test at the initial stage of watering moulding without moving test specimens, and continuous and automatic test.
Description
technical field [0001] The invention relates to a cement-based material expansion / shrinkage stress test method, which can evaluate the expansion effect of an expansion agent used to prepare shrinkage-compensating concrete, and belongs to the technical field of cement-based material testing. Background technique [0002] Shrinkage-compensated concrete refers to the concrete that is mixed with expansive agent or expansive cement to produce moderate expansion and certain self-stress under certain constraints. It is mainly used for structural self-waterproofing, filling expansion second-phase project, continuous pouring reinforced concrete project and mass concrete project for extending the distance between building expansion joints or post-casting strips. The expansion component relies on its own chemical reaction or reacts with other components of the cement to produce a certain limited expansion compensation or partially compensate for the shrinkage of the concrete during the...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more
Application Information
Patent Timeline
Application Date:The date an application was filed.
Publication Date:The date a patent or application was officially published.
First Publication Date:The earliest publication date of a patent with the same application number.
Issue Date:Publication date of the patent grant document.
PCT Entry Date:The Entry date of PCT National Phase.
Estimated Expiry Date:The statutory expiry date of a patent right according to the Patent Law, and it is the longest term of protection that the patent right can achieve without the termination of the patent right due to other reasons(Term extension factor has been taken into account ).
Invalid Date:Actual expiry date is based on effective date or publication date of legal transaction data of invalid patent.
Login to view more