CN1299115C - Induced cracking process for crack resistant performance test of cement base material and apparatus thereof - Google Patents
Induced cracking process for crack resistant performance test of cement base material and apparatus thereof Download PDFInfo
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- CN1299115C CN1299115C CNB2004100614921A CN200410061492A CN1299115C CN 1299115 C CN1299115 C CN 1299115C CN B2004100614921 A CNB2004100614921 A CN B2004100614921A CN 200410061492 A CN200410061492 A CN 200410061492A CN 1299115 C CN1299115 C CN 1299115C
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Abstract
The present invention relates to an induced cracking method and a device thereof for testing the crack resistance performance of cement-based materials, which has the advantages of short testing time and high correctness. A frame body with screw bolts is used for inducing the fast cracking of cement-based materials, and a partition board is arranged in the frame body; cement-based materials are cast between the partition board and the frame body, the screw bolts are covered in the cement-based materials, the upper end of the partition board is exposed outside the cement-based materials, and the lower end of the partition board and the lower part of the frame body are on the same plane surface. The present invention has the advantages of high accuracy, high adaptability, simple structure and easy use, the early cracking development trend of the cement-based materials can be conveniently, fast and accurately measured, and testing objectives are various cement-based materials utilized in civil engineering. For fast testing the crack resistance performance of the cement-based materials, the device can effectively shorten the time of testing the crack resistance performance of the cement-based materials and greatly reduce the randomness of cracks under the condition that the sufficient precision of test results is ensured without changing the uniformity of the cement-based materials.
Description
Technical field:
The present invention relates to a kind of anti-cracking performance of cement base material test induced cracking method and device thereof.To the various cement-based materials that adopted in the civil engineering work, all available the present invention tests its cracking resistance apace.
Background technology:
The cracking resistance of cement-based material structure has become the problem that people extremely are concerned about, wide application and measure big concrete particularly, but the domestic and international method of comparatively unified testing anti-cracking performance of cement base material not also so far also lacks this important link of cracking resistance to the quality inspection of commerical ready-mixed concrete.At present the method that adopts as flat band method, ring method etc., respectively has its advantage and defective, the outstanding problem of existing general character be the test duration long, randomness is big, be not easy to use.External also relevant for the report of the method for testing of accelerating the cement-based material cracking time, promptly on the basis of flat band method, be parallel to edges of boards and place the triangle steel bar of some height less than plate thickness, because the top of triangle steel bar is lower than the height of the dull and stereotyped end face of cement-based material, has shortened the cement-based material crack time of occurrence and the crack is taken place along triangle steel bar apical position.But, this method makes in the flat board cement-based material inhomogeneous, above the top of triangle steel bar, the thickness of cement-based material is less than other positions, thereby cause the inconsistent of plastic set amount, promptly above steel bar settling amount less than the sedimentation of its both sides, thereby crack along the steel bar direction appears above steel bar, rather than occur in the cement-based material structure owing to shrink the crack that causes.Thereby influenced the accuracy of testing anti-cracking performance of cement base material.Simultaneously for concrete, this method also exists in the flat board concrete material inhomogeneous, and above the top of triangle steel bar, concrete coarse aggregate content influences precision of test result less than the problems such as coarse aggregate content of other position.At present, related research units, commerical ready-mixed concrete producer and engineering construction unit all are sought after a kind of device of quick, accurate testing anti-cracking performance of cement base material.
Summary of the invention:
The invention solves the prior art test duration long, randomness is big, the inaccurate defective of test result, and a kind of test duration is short, accuracy is high anti-cracking performance of cement base material test induced cracking method and device thereof are provided.
Technical scheme of the present invention is as follows:
1, anti-cracking performance of cement base material test induced cracking method is characterized in that: it is the quick cracking that the framework that is provided with the strap bolt of dividing plate in adopting is induced cement-based material; Casting cement sill between dividing plate and framework, bolt is coated in the cement-based material, thereby cement-based material is formed constraint; Expose outside the cement-based material upper end of dividing plate, and the bottom of its lower end and framework 1 at grade.The cross-sectional area that makes this place's cement-based material by dividing plate is less than other section, and the height of dividing plate should make the cement-based material of this part be disconnected by dividing plate fully more than or equal to the height of framework, thereby induces cement-based material to ftracture at the cross-sectional area smaller part.
2, anti-cracking performance of cement base material test induced cracking device, it comprises the framework of strap bolt, it is characterized in that: be provided with dividing plate in framework.
The invention has the beneficial effects as follows that can easily and fast, accurately measure the early crack development trend of cement-based material, tested object is various cement-based materials used in the civil engineering work.Degree of accuracy height of the present invention, applicability is strong, using method is easy.The inventive method can be in the homogeneity that does not change cement-based material, guarantee that test result has under the situation of enough accuracy, shortens the test duration of anti-cracking performance of cement base material effectively, has reduced the randomness that the crack occurs greatly.
Make the area of this section less than other sections owing to add dividing plate, make the suffered stress of the cement-based material of this section greater than other sections, thereby the development in guiding, acceleration crack, the homogeneity that does not influence its cement-based material cast simultaneously again is that each position cement-based material thickness and aggregate thereof are evenly distributed.Guiding by dividing plate, morning time that the crack of cement-based material occurs, crack location relative fixed, Number of Fractures are determined relatively, fracture width greatly and crack fast-growth, shortened observation time, be convenient to the cracking time of observation water cement-based material, fracture width, length, and error is little, and is quick and convenient.Shortcomings such as the identical crack that makes of sectional area of having eliminated owing to each section of cement-based material in framework occurs at random, and the time that the crack occurs is slow, and the crack speed of development is slow, and Number of Fractures is many, and fracture width is little, and the observation difficulty is big and the time is long, and accuracy is little.
Description of drawings:
Fig. 1 is the structural representation of embodiment 1 unilateral constrain rectangular slab opposite side baffle plate device.Wherein: (a) being the one-piece construction synoptic diagram of not casting cement sill device, (b) is the one-piece construction synoptic diagram of casting cement sill device, (c) is the sectional view of casting cement sill device.
Fig. 2 is the structural representation of embodiment 2 two-way constraint rectangular slab opposite side baffle plate devices.
Fig. 3 is the structural representation of embodiment 3 two-way constraint rectangular slab four side partition devices.
Fig. 4 is the structural representation of embodiment 4 two-way constraint rectangular slab central dividing plate devices.
Fig. 5 is the structural representation of embodiment 5 unilateral constrain rectangular slab central dividing plate devices.
Fig. 6 is a kind of structural representation of dividing plate.
Fig. 7 is the another kind of structural representation of dividing plate.
Label declaration: 1 is framework; 2 is bolt; 3 is dividing plate; 4 is cement-based material; 5 is base plate.
Embodiment:
Shown in Fig. 1-5, the present invention is provided with the quick cracking that the framework 1 of the strap bolt 2 of dividing plate 3 is induced cement-based material in adopting; Casting cement sill 4 between dividing plate 3 and framework 1, bolt 2 is coated in the cement-based material 4, expose outside the cement-based material 4 upper end of dividing plate 3, and the cross-sectional area that makes the dividing plate place by dividing plate 3 is less than other section, thereby induce cement-based material 4 to ftracture at the cross-sectional area smaller part.
Anti-cracking performance of cement base material test induced cracking device of the present invention, it comprises the framework 1 of strap bolt 2, it is characterized in that: be provided with dividing plate 3 in framework 1.
Framework 1 can directly be placed or be fixed on the table top, also can thereunder dispose fixed base plate, so that cement-based material is cast in the framework 1 of base plate or table top top.Framework 1 is a rectangle frame.
Dividing plate 3 must have enough rigidity, in order to avoid owing to the distortion of dividing plate 3 influences reliability of testing result; The smooth surface of dividing plate 3 is smooth, in order to avoid cement-based material is formed constraint and influences reliability of testing result; Dividing plate 3 should be the circular arc type tip with the cement-based material contact jaw, in order to avoid because the concentrated reliability of testing result that influences of stress.Make the area of this section less than other sections owing to add dividing plate 3, make the suffered stress of the cement-based material of this section greater than other sections, thereby the development in guiding, acceleration crack, the homogeneity that does not influence its cement-based material cast simultaneously again is that each position cement-based material thickness and aggregate thereof are evenly distributed.Guiding by dividing plate 3, morning time that cement-based material crack occurs, crack location relative fixed, Number of Fractures are determined relatively, fracture width greatly and crack fast-growth, shortened observation time, be convenient to the cracking time of observation water cement-based material, fracture width, length, and error is little, and is quick and convenient.Shortcomings such as slow owing to the identical time that makes the crack be appearance at random, crack appearance of sectional area of each section in cement-based material, that the crack speed of development is slow, Number of Fractures is many, fracture width is little, the observation difficulty is big and the time is long, accuracy is little have been eliminated.
In Fig. 1～Fig. 5, base plate 5 or table top should have enough rigidity and smooth surface smooth, in order to avoid because the distortion of base plate 5 or table top, the perhaps frictional constraint of base plate 5 or table top and influence reliability of testing result; Framework 1 should have enough rigidity, causes framework 1 distortion to avoid because cement-based material shrinks the stress that is produced, and influences precision of test result; Bolt 2 is to be fixed on the framework 1 so that cement-based material is formed constraint.In Fig. 1～Fig. 3, dividing plate 3 is to be fixed on the framework 1, simultaneously the bottom of dividing plate 3 should with the bottom of framework at grade, and the height of dividing plate 3 should be not less than the height of framework 1, to cut off cement-based material fully; Dividing plate among Fig. 4 and Fig. 5 is to be fixed on base plate 5 or the table top, in order to avoid owing to rocking of dividing plate 3 influences reliability of testing result.
Embodiment 1:
As shown in Figure 1: according to the size of rectangle framework 1 and the size of cement-based material contraction, in the rectangle framework 1 of unilateral constrain, along be provided with perpendicular to the free margins of rectangle framework 1 1～10 pair long be the dividing plate 3 of 1/10～2/5 framework, the 1 binding side length of side, with the even five equilibrium of the edge of framework 1, thereby reduce the sectional area of corresponding section, the stress that produces in this section place when cement-based material shrinks is greater than other section, thereby quicken the generation in crack, and guiding crack results from this cross section.Determined position and Number of Fractures that the crack may occur relatively, and morning time, development that the crack occurs are fast, fracture width is big, is easy to observation, the time of observation is short, the accuracy height.
Embodiment 2:
As shown in Figure 2, according to the size of framework 1 and the size of cement-based material contraction, in the rectangle framework 1 of two-way constraint, along 1～10 pair of dividing plate 3 being set perpendicular to the long frame edge of rectangle framework 1, dividing plate 3 length are 1/10～2/5 of rectangle framework 1 length of short sides, framework 1 is grown the even five equilibrium in limit, thereby reduce the sectional area of corresponding section, the stress that produces in this section place when cement-based material shrinks is greater than other section, thereby quicken the generation in crack, and guiding crack results from this cross section.
Embodiment 3:
As shown in Figure 3: in the rectangle framework 1 of two-way constraint, respectively in the middle of its four edges 1 along a dividing plate 3 being set perpendicular to the edge of framework 1, dividing plate 3 length be its parallel framework 1 edge length 1/10～2/5, thereby reduce the sectional area of corresponding section.
Embodiment 4:
As shown in Figure 4: according to the size of framework 1 and the size of cement-based material contraction, in the rectangle framework 1 of two-way constraint, along being parallel to the minor face frame, adding 1～10 pair of dividing plate 3 in the centre of rectangle framework 1, the length of dividing plate 3 is 1/10～4/5 of rectangle framework 1 length of short sides, with the even five equilibrium of the center section of cement-based material 4, thereby reduce the sectional area of corresponding section.
Embodiment 5:
As shown in Figure 5: according to the size of framework 1 and the size of cement-based material contraction, be provided with 1～10 in the centre of the rectangle framework 1 of unilateral constrain and be parallel to the restrained end frame and length is the dividing plate 3 of 1/10～4/5 framework length of side, with the even five equilibrium of the center section of cement-based material 4, thereby reduce the sectional area of corresponding section, and guiding crack results from this cross section.
Claims (10)
1, a kind of anti-cracking performance of cement base material test induced cracking method is characterized in that: it is the framework (1) that is provided with the strap bolt (2) of dividing plate (3) in the adopting quick cracking of inducing cement-based material (4); Casting cement sill (4) between dividing plate (3) and framework (1), bolt (2) are coated in the cement-based material (4), and expose outside the cement-based material (4) upper end of dividing plate (3), and the bottom of its lower end and framework (1) at grade.
2, a kind of anti-cracking performance of cement base material test induced cracking device, it comprises the framework of strap bolt, it is characterized in that: be provided with dividing plate (3) in framework (1).
3, anti-cracking performance of cement base material test induced cracking device according to claim 2, it is characterized in that: the framework that is adopted (1) is rectangle frame, framework (1) is directly placed or is fixed on the table top, or thereunder disposing fixing base plate (5), table top or base plate (5) should be smooth smooth; Dividing plate (3) must have enough rigidity, and dividing plate (3) is the circular arc type tip with cement-based material (4) contact jaw, and the smooth surface of dividing plate (3) is smooth.
4, according to claim 2 or 3 described anti-cracking performance of cement base material test induced cracking devices, it is characterized in that: an end of dividing plate (3) is fixed on the internal face of framework (1).
5, anti-cracking performance of cement base material test induced cracking device according to claim 4, it is characterized in that: in the rectangle framework (1) of unilateral constrain, along 1～10 pair, length are set perpendicular to the free margins of rectangle framework (1) is the dividing plate (3) of 1/10～2/5 framework (1) the binding side length of side, with the even five equilibrium of free margins of framework (1).
6, anti-cracking performance of cement base material test induced cracking device according to claim 4, it is characterized in that: in the rectangle framework (1) of two-way constraint, along 1～10 pair of dividing plate (3) being set perpendicular to the long frame edge of rectangle framework (1), dividing plate (3) length is 1/10～2/5 of rectangle framework (1) length of short sides, with the even five equilibrium of edge.
7, anti-cracking performance of cement base material test induced cracking device according to claim 4, it is characterized in that: in the rectangle framework (1) of two-way constraint, respectively in the middle of its four edges along a dividing plate (3) being set perpendicular to the edge of framework (1), dividing plate (3) length be framework (1) parallel edges length 1/10～2/5, thereby reduce the sectional area of corresponding section.
8, anti-cracking performance of cement base material test induced cracking device according to claim 3, it is characterized in that: dividing plate (3) is positioned over the centre in the framework (1), and is fixed on base plate (5) or the table top.
9, anti-cracking performance of cement base material test induced cracking device according to claim 8, it is characterized in that: in the rectangle framework (1) of two-way constraint, along being parallel to the minor face frame, adding 1～10 pair of dividing plate (3) in the centre of rectangle framework (1), the length of dividing plate (3) is 1/10～4/5 of rectangle framework (1) length of short sides, with the even five equilibrium of center section of cement-based material (4).
10, anti-cracking performance of cement base material test induced cracking device according to claim 8, it is characterized in that: be provided with 1～10 in the centre of the rectangle framework (1) of unilateral constrain and be parallel to the restrained end frame and length is the dividing plate (3) of 1/10～4/5 restrained end length of side, the even five equilibrium of center section of cement-based material (4).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100614921A CN1299115C (en) | 2004-12-31 | 2004-12-31 | Induced cracking process for crack resistant performance test of cement base material and apparatus thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2004100614921A CN1299115C (en) | 2004-12-31 | 2004-12-31 | Induced cracking process for crack resistant performance test of cement base material and apparatus thereof |
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| CN1632575A CN1632575A (en) | 2005-06-29 |
| CN1299115C true CN1299115C (en) | 2007-02-07 |
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| CNB2004100614921A Expired - Fee Related CN1299115C (en) | 2004-12-31 | 2004-12-31 | Induced cracking process for crack resistant performance test of cement base material and apparatus thereof |
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Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1866004B (en) * | 2006-06-09 | 2010-05-12 | 宁波工程学院 | Test method for crack-resistant performance of concrete and outside-square inside-round test apparatus therefor |
| CN101603897B (en) * | 2009-05-27 | 2011-03-23 | 水利部交通部电力工业部南京水利科学研究院 | Adjustable multiple stress induced cracking device for concrete |
| CN102759612B (en) * | 2012-07-27 | 2015-04-29 | 广西壮族自治区水利科学研究院 | Multi-angle cement concrete surface crack resistance performance inspection device |
| CN102798707B (en) * | 2012-09-09 | 2014-08-13 | 中国水利水电第三工程局有限公司 | Concrete restrained contraction ring crack resistance test device and test method |
| CN103954644A (en) * | 2014-05-12 | 2014-07-30 | 中国民航机场建设集团公司 | Device for simulating crack expanding form of carbon fiber concrete airfield pavement |
| CN104535431B (en) * | 2014-12-30 | 2017-11-17 | 中建商品混凝土有限公司 | Crack resistance evaluation method and device of the concrete under temperature, contraction coupling |
| CN106053329A (en) * | 2016-05-19 | 2016-10-26 | 扬州大学 | Method for testing air shrinkage resistant performance of plastering material |
| CN108414732A (en) * | 2018-05-28 | 2018-08-17 | 华南理工大学 | A kind of round outside but spuare inside crack resistance |
| CN108828198B (en) * | 2018-06-12 | 2021-08-20 | 北京工业大学 | Early concrete crack induction testing device |
| CN109061118A (en) * | 2018-07-24 | 2018-12-21 | 华南理工大学 | A kind of test device of quick measurement concrete early-stage crack resistance |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2606894Y (en) * | 2003-04-03 | 2004-03-17 | 中国建筑材料科学研究院 | Limiting expansion and contraction device for concrete |
| CN1547000A (en) * | 2003-12-09 | 2004-11-17 | 中国建筑材料科学研究院 | Cement mortar and concrete shrinkage stress testing method |
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2004
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2606894Y (en) * | 2003-04-03 | 2004-03-17 | 中国建筑材料科学研究院 | Limiting expansion and contraction device for concrete |
| CN1547000A (en) * | 2003-12-09 | 2004-11-17 | 中国建筑材料科学研究院 | Cement mortar and concrete shrinkage stress testing method |
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