CN207703862U - A kind of Mortar shrinkage test stand - Google Patents

Abstract

The utility model provides a kind of Mortar shrinkage test stand, which includes：Bottom plate, first support bar, second support bar and amesdial；The first support bar is vertical with the bottom plate to fix, the second support bar is slidably connected and parallel with the bottom plate with the first support bar, the amesdial is arranged in the second support bar, the bottom plate is equipped with the groove that can place mortar specimen, the mortar specimen is equipped with feeder head, and the gauge head of the amesdial faces the feeder head.Mortar shrinkage test stand provided by the utility model is not necessarily to mobile mortar specimen during the test, and easy for installation, space hold is few, and accuracy is high, can measure with long-term shrink in early days, reusable.

Description

A mortar shrinkage test stand

technical field

The utility model relates to the field of measuring equipment for building materials, in particular to a mortar shrinkage test frame.

Background technique

The problem of shrinkage and cracking of cement-based materials has always been a difficult problem in the construction industry. In view of the volume shrinkage caused by the chemical reaction of cement itself, the shrinkage of cement products is unavoidable. In recent years, the increase in cement fineness and the use of ultra-fine mineral admixtures have increased the autogenous shrinkage and drying shrinkage of building materials such as concrete and mortar, and shrinkage is often accompanied by cracking. Cracks have a great impact on the durability of the structure. The existence of cracks allows the aggressive medium in the environment to enter the structure, causing various types of erosion such as carbonization, and seriously reducing the durability of the structure.

Aiming at the degree of shrinkage and cracking of cheap cement-based materials, domestic and foreign scholars have done a lot of research and developed a series of testing instruments and methods, such as the flat-plate constrained shrinkage test method proposed by Kraai of San Jose State University, and the ring method proposed by Carlson. And the uniaxial restraint testing machine developed by the Technical University of Munich in Germany provides a test method suitable for different restraint conditions, different types of shrinkage, and different degrees of cracking for the evaluation of shrinkage cracking. During the research process, many scholars have pointed out the shortcomings of these test methods Propose their own improvement methods. Most of the above test methods are used to evaluate the shrinkage and cracking of concrete. At present, the methods used to evaluate the shrinkage of mortar are relatively simple, and there are generally vertical mortar shrinkage meters and specific length meters.

When using the vertical mortar shrinkage tester to test the shrinkage of mortar, the length of each specimen of each age should be measured according to the marked test direction. The placement of each specimen is the key factor affecting the measurement accuracy, and the human error is relatively large. . The shrinkage value measured by the ratio meter test method is the shrinkage value of the mortar after being restrained, and cannot accurately reflect the shrinkage state of the mortar. Chinese patent CN 206378429U discloses a device for testing the shrinkage of cement mortar. The device uses a laser triangular reflective displacement sensor, which is a non-destructive, non-contact test method with high test accuracy, but the device has strict requirements on the test environment. And the equipment is expensive, not suitable for mass applications.

Utility model content

In order to overcome the above problems or at least partly solve the above problems, the utility model provides a mortar shrinkage test frame, including: a bottom plate, a first support rod, a second support rod and a dial indicator; the first support rod and the The base plate is vertically fixed, the second support rod is slidingly connected with the first support rod and parallel to the base plate, the dial indicator is arranged on the second support rod, and the base plate is provided with a The groove of the mortar test piece, the mortar test piece is provided with a contraction head, and the measuring head of the dial gauge is directly facing the contraction head.

Preferably, the end of the first support rod is provided with threads, and the first support rod is vertically fixed to the bottom plate through the threads.

Preferably, the second support rod is slidably connected to the first support rod through a first adjustment block.

Preferably, the first adjusting block is provided with a first U-shaped groove and a second U-shaped groove, the first support rod passes through the first U-shaped groove and is connected with the first adjusting block, and the second The support rod passes through the second U-shaped groove and is connected with the first adjusting block.

Preferably, the ends of the first U-shaped groove and the second U-shaped groove are respectively provided with locking bolts.

Preferably, the dial indicator is set on the second support rod through the second adjustment block, and the second adjustment block is provided with a third U-shaped groove and a fourth U-shaped groove, and the dial indicator wears The third U-shaped groove is connected to the second support column, and the second support column is connected to the second adjustment block through the fourth U-shaped groove.

Preferably, the ends of the third U-shaped groove and the fourth U-shaped groove are respectively provided with locking bolts.

Preferably, there are multiple dial gauges and the grooves, and the dial gauges correspond to the grooves one by one.

Preferably, there are three dial gauges and three grooves.

Preferably, a rubber pad is provided on the side of the bottom plate away from the groove.

The mortar shrinkage test frame involved in the utility model is a triple frame, and there is no need to move the mortar test block during the test process. The test frame of the utility model is easy to install, easy to operate, low in price, takes up less space, and has high accuracy. Early and long-term shrinkage All are measurable and reusable.

Description of drawings

Fig. 1 is a schematic diagram of a mortar shrinkage test stand in a preferred embodiment of the utility model;

Fig. 2 is the pre-embedded shrinkage head of the mortar test piece in the utility model.

Wherein, 1 is the bottom plate, 2 is the first support rod, 3 is the second support rod, 4 is a dial gauge, 41 is a probe, 5 is a groove, 6 is a first adjustment block, and 7 is a second adjustment block.

Detailed ways

Below in conjunction with embodiment, the specific implementation manner of the present utility model is described in further detail. The following examples are used to illustrate the utility model, but not to limit the scope of the utility model.

In the description of the present utility model, unless otherwise specified, "plurality" refers to two or more than two. The terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, or a mechanical connection, or an electrical connection, which can be directly connected or through an intermediate connection. An indirect connection through a medium may also be an internal connection between two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention depending on the specific circumstances.

The utility model provides a mortar shrinkage test frame, comprising: a bottom plate 1, a first support rod 2, a second support rod 3 and a dial indicator 4, the first support rod 2 is vertically fixed to the bottom plate 1, and the second support rod 3 Slidingly connected with the first support rod 2 and parallel to the bottom plate 1, the dial indicator 4 is arranged on the second support rod 3, the bottom plate 1 is provided with a groove 5 capable of accommodating the mortar test piece, and the mortar test piece is provided with a shrinking head , the measuring head of the dial gauge 4 is facing the shrinking head.

Wherein, after the mortar mixture is stirred, it is loaded into a mortar test piece with a shrinking head, and the mortar test piece is placed in the groove 5 of the bottom plate 1 . The second support rod 3 slides up and down on the first support rod 2 to adjust the shrinkage of the measuring head of the dial gauge 4 and the mortar specimen in the groove 5 on the bottom plate 1 parallel to the second support rod 3 The test is completed by touching the head and reading the shrinkage value at the desired age. There is no need to move the mortar specimen during the test, the operation is simple, the accuracy is high, and both early and long-term shrinkage can be measured.

Wherein, the structure of the shrinkage head of the mortar specimen may be as shown in FIG. 2 .

In the present utility model, usually after the mortar mixture is stirred, it is packed into a test mold with a shrinkage head, and after the curing is completed, the demoulded mortar test piece is placed in the groove of the bottom plate.

Wherein, the groove is preferably a semicircular groove. In the present invention, a semicircular groove with a diameter of 6 mm can be used.

In this implementation model, the test mold can be made according to the "Basic Performance Test Method for Building Mortar" (JGJ 70-2009), after the mortar mixture is stirred, it is put into the test mold with a shrinkage head, and it is placed in the pre-curing room for 4 hours. Finally, smooth the surface of the mortar, and remove the mold after the mortar belt mold is cured for 7 days in the standard curing room. After demoulding, the mortar specimen with the shrinkage head is placed in the groove of the test frame, and the probe of the dial indicator is adjusted to be in contact with the shrinkage head of the mortar specimen, and the shrinkage value can be read when the desired age is reached. .

Among them, the temperature of the pre-raising room can be (20±5)°C; the temperature of the standard raising room is (20±2)°C, and the humidity is above 95%; the temperature of the shrinking room is (20±2)°C, and the humidity is (60°C). ±5)%.

In a preferred embodiment, the end of the first support rod 2 is provided with threads, and is vertically fixed to the bottom plate 1 through the threads. Specifically, the base plate 1 may be provided with a threaded hole, and the threaded end of the first support rod 2 is screwed to the threaded hole of the base plate 1 to complete the vertical fixing of the first support rod 2 and the base plate 1 .

Wherein, the position of the threaded hole can be adjusted according to actual needs. In order to ensure that the measuring head of the dial indicator arranged on the second support rod 3 is facing the shrinkage head of the mortar specimen in the groove of the bottom plate, the threaded hole is usually set at 10 mm from the long side of the bottom plate and 10 mm from the short side of the bottom plate. 10-35mm.

In a preferred embodiment, the second support rod 3 can be slidably connected to the first support rod 2 through the first adjustment block 6 .

Wherein, a first U-shaped groove and a second U-shaped groove may be provided on the first regulating block 6, the first support rod 2 passes through the first U-shaped groove and is connected with the first regulating block 6, and the second supporting rod 3 passes through the first U-shaped groove. It is connected with the first regulating block 6 through the second U-shaped groove.

Wherein, locking bolts may be provided at the ends of the first U-shaped groove and the second U-shaped groove respectively. The locking bolts arranged on the first U-shaped groove are used to connect the first support rod 2 with the first adjustment block 6 . The locking bolts arranged on the second U-shaped groove are used to connect the second support rod 3 with the first adjustment block 6, and ensure that the second support rod is parallel to the bottom plate, and the second support rod and the first adjustment block are connected by the locking bolts. A support rod is slidably connected.

Specifically, corresponding through holes may be provided on the two long sides of the first U-shaped groove, and the locking bolts pass through the through holes on the two long sides to fix and lock the first support rod 2 and the first adjustment block 6. Similarly, corresponding through holes may be provided on the two long sides of the second U-shaped groove, and the locking bolts pass through the through holes on the two long sides to fix the second support rod 2 and the first adjusting block 6 .

In a preferred embodiment, the dial indicator 4 is arranged on the second support rod 3 through the second adjustment block 7 . Wherein, the second adjusting block 7 can be provided with a third U-shaped groove and a fourth U-shaped groove, the dial indicator 4 is connected with the second support rod 3 through the third U-shaped groove, and the second support rod 3 passes through the fourth U-shaped groove. The U-shaped groove is connected with the second regulating block 7 .

Wherein, locking bolts may be provided at the ends of the third U-shaped groove and the fourth U-shaped groove respectively. The locking bolt arranged on the third U-shaped groove is used to connect the dial indicator 4 with the second adjusting block 7 . The locking bolts arranged on the fourth U-shaped groove are used to connect the second support rod 3 with the second adjustment block 7 . By adjusting the locking bolts on the third U-shaped groove and the fourth U-shaped groove, the measuring head of the dial indicator is facing the shrinking head of the test piece.

Specifically, corresponding through holes may be provided on the two long sides of the third U-shaped groove, and the locking bolts pass through the through holes on the two long sides to fix and lock the dial gauge 4 and the second adjustment block 7 . Similarly, corresponding through holes can also be provided on the two long sides of the fourth U-shaped groove, and the locking bolts pass through the through holes on the two long sides to fix the dial indicator 4 and the second adjusting block 7 .

In a preferred embodiment, a plurality of grooves are provided on the bottom plate, corresponding to a plurality of dial gauges, so as to realize simultaneous measurement of a plurality of test pieces. When multiple dial gauges and multiple grooves are provided, in order to measure the shrinkage values of multiple test pieces more accurately and simultaneously, multiple second adjustment blocks can be set on the second support rod to fix multiple dial gauges , so that the probe of each dial gauge is facing the contraction head of the specimen in the groove corresponding to the dial gauge.

In a preferred embodiment, three semicircular grooves are preferably provided on the bottom plate, and three mortar test blocks with a size of 40×40×160 mm can be measured at the same time. Correspondingly, three second adjustment blocks are arranged on the second support rod 3, and three dial gauges are respectively arranged on the second support rod 3, and the measuring heads of the three dial gauges respectively correspond to the The shrinkage head of the test piece in the groove corresponding to the dial indicator, so as to realize simultaneous measurement.

In a preferred embodiment, in order to reduce the impact of external vibration on the test frame, a rubber pad can be provided on the side of the bottom plate away from the groove. It is also possible to place the test frame on the rubber pad during the test.

In a preferred embodiment, as shown in Figure 1, a kind of mortar shrinkage test frame is provided: the threaded end of the first support rod 2 is screwed with the threaded hole of the bottom plate 1, the threaded hole position is 10mm away from the long side of the bottom plate 1, and the screw thread The hole position is 10-35mm according to the short side of the bottom plate. The diameter of the first support rod 2 may be 120mm, and the length of the non-threaded part is 260mm. After the first support rod 2 is vertically fixed, the second support rod 3 is connected to the first support rod 2 through the first adjustment block 6 , and the three dial gauges 4 are connected to the second support rod through the second adjustment block 7 . Simultaneously by adjusting the bolts on the first adjusting block 6 and the second adjusting block 7 to ensure that the measuring head of each dial gauge installed on the second support rod is facing the shrinking head of the test piece in its corresponding bottom plate groove.

After the mortar mixture is stirred, put it into the test mold with the shrinkage head. After the curing is completed, place the mortar sample with the shrinkage head on the bottom plate, and move the three dial gauges to the same level as the three gauges through the bolts. contact with the contraction head of the first test piece, tighten the locking bolts of the three second adjustment blocks to fix the position of the dial indicator. Push the second support rod to the required height, which ensures that the shrinkage head of the dial indicator is in contact with the mortar specimen and can slide freely, and tighten the locking bolt of the first adjustment block to fix the height of the support rod II. After the installation is completed, place the test device on the rubber pad of the shrinkage chamber test bench, and read the shrinkage value when the desired age is reached.

Finally, the method of the present utility model is only a preferred embodiment, and is not intended to limit the protection scope of the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (10)

1. A kind of mortar shrinkage test stand, is characterized in that, comprises: base plate, first support rod, second support rod and dial gauge; Described first support rod is vertically fixed with described base plate, and described second support rod Slidingly connected with the first support rod and parallel to the bottom plate, the dial indicator is arranged on the second support rod, the bottom plate is provided with a groove for placing a mortar test piece, and the mortar test piece The part is provided with a shrinking head, and the measuring head of the dial gauge is facing the shrinking head. 2. The mortar shrinkage test stand according to claim 1, characterized in that, the end of the first support rod is provided with threads, and the first support rod is vertically fixed to the bottom plate through the threads. 3. The mortar shrinkage test stand according to claim 1, wherein the second support rod is slidably connected to the first support rod through a first adjusting block. 4. The mortar shrinkage test frame according to claim 3, wherein a first U-shaped groove and a second U-shaped groove are arranged on the first adjusting block, and the first support rod passes through the first U-shaped groove. A U-shaped groove is connected with the first adjusting block, and the second support rod passes through the second U-shaped groove and is connected with the first adjusting block. 5. The mortar shrinkage test stand according to claim 4, characterized in that, the ends of the first U-shaped groove and the second U-shaped groove are respectively provided with locking bolts. 6. The mortar shrinkage test stand according to any one of claims 1 to 5, characterized in that, the dial indicator is arranged on the second support bar through a second adjustment block, and the second adjustment block A third U-shaped groove and a fourth U-shaped groove are provided on the top, the dial gauge passes through the third U-shaped groove and is connected to the second support rod, and the second support rod passes through the fourth U-shaped groove. The groove is connected with the second regulating block. 7. The mortar shrinkage test stand according to claim 6, characterized in that, the ends of the third U-shaped groove and the fourth U-shaped groove are respectively provided with locking bolts. 8 . The mortar shrinkage test stand according to claim 1 , wherein there are multiple dial gauges and multiple grooves, and the dial gauges correspond to the grooves one by one. 9. The mortar shrinkage test stand according to claim 8, wherein there are three dial gauges and three grooves. 10. The mortar shrinkage test stand according to claim 1, characterized in that a rubber pad is provided on the side of the bottom plate away from the groove.