Test method for evaluating freezing and thawing resistance of cement-based waterproof bonding layer

A technology of waterproof adhesive layer and test method, which is applied in the direction of testing material strength by applying stable shear force, testing material strength and strength characteristics by applying stable tension/pressure, and achieving obvious economic and social benefits

Inactive Publication Date: 2017-10-17

BEIJING UNIVERSITY OF CIVIL ENGINEERING AND ARCHITECTURE +1

5 Cites 5 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0010] In the selection of waterproof adhesive layer materials, researchers generally choose asphalt and specia...

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

Abstract

The invention relates to a test method for evaluating the freezing and thawing resistance of a cement-based waterproof bonding layer. The method includes the steps of firstly, wetting a cement concrete block with an acrylic emulsion; secondly, smearing a cement-based material; thirdly, placing the cement concrete block smeared with the cement-based material under normal temperature; fourthly, laying an asphalt mixed material when the cement-based material is in an initial set state; fifthly, maintaining the cement concrete composite test piece with the asphalt mixed material under normal temperature; sixthly, cutting the maintained cement concrete composite test piece into a shear test piece and a drawing test piece; seventhly, performing freezing and thawing on each of the shear test piece and the drawing test piece in a rubber test box; eighthly, maintaining the test pieces in water; ninthly, sequentially measuring the shear strength and drawing strength of the test pieces after difference times of freezing and thawing cycles; tenthly, determining a method most suitable for evaluating the freezing and thawing resistance of a cement-based waterproof bonding layer material. The method can guide the specific application of the cement-based waterproof bonding layer material in cement concrete decks, and an applicable test method capable of sufficiently evaluating the freezing and thawing resistance of the cement-based waterproof bonding layer material is provided.

Application Domain

Material strength using tensile/compressive forcesMaterial strength using steady shearing forces

Technology Topic

EmulsionAsphalt +7

Image

Examples

Experimental program(2)

Example Embodiment

[0045] Example 1:

[0046] A test method for evaluating the freeze-thaw resistance of cement-based waterproof bonding layer, including the following steps:

[0047] 1) Use acrylic emulsion to wet the prefabricated C40 cement concrete block of 300mm×300mm×50mm, the dosage is 200g/m 2 , Let stand for 5min at room temperature;

[0048] 2) Spread cement-based material on the wet cement concrete block, and use a cement spatula to smooth the thickness to 4mm; the cement base is made of Portland cement, machine-made sand, acrylic emulsion, water, and additives. Proportional composition.

[0049] 3) Put the cement concrete block coated with cement-based materials at room temperature for 0.5h;

[0050] 4) Add AC-13 asphalt mixture when the cement-based material is in the initial setting state;

[0051] 5) Cure the cement concrete composite specimens with asphalt mixture at room temperature for 14 days;

[0052] 6) Cut the cured cement concrete composite specimen into 100mm×100mm×100mm shear specimens, and pavement layer 50mm×50mm×50mm + cement concrete slab layer 70mm×70mm×50mm, and use The drawing head is glued with epoxy resin;

[0053] 7) Put 20 shear test pieces and 20 drawing test pieces into the rubber test box, add drinking water to make it cover the top surface of the test piece by 2mm, and then freeze in the refrigerator at -18℃ for 4h; Put the specimen frozen for 4 hours into 60℃ water and melt for 1 hour;

[0054] 8) Before the shear test and pull test, keep the test piece in 25℃ water for 2h;

[0055] 9) Sequentially determine the shear strength and pull-out strength of the specimens after different freeze-thaw cycles (0, 5, 10, 15, 20, 25).

[0056] (1) Shear test results

[0057] Measure the shear strength of 100mm×100mm×100mm composite small specimens with different cycles (0, 5, 10, 15, 20, 25). Each cycle uses 4 parallel specimens and the shear rate is 10mm /min, the shear angle is 45°. The results of the shear test are shown in Table 1.

[0058] Table 1 Shear strength of specimens with different freeze-thaw cycles

[0059]

[0060]

[0061] by figure 1 It can be seen that as the number of freeze-thaw cycles increases, the shear strength of the cement-based waterproof adhesive layer gradually decreases. From 0 freeze-thaw cycles to 10 freeze-thaw cycles, the shear strength decreases by 32.6%, and the rate of decrease is 0.093MPa /Time, the shear strength dropped by 18.8% from 10 freeze-thaw cycles to 25 freeze-thaw cycles, and the rate of decrease was 0.024MPa/time. This shows that the first 10 freeze-thaw cycles of the cement-based waterproof adhesive layer have a greater impact on its shear strength. After 10 freeze-thaw cycles, the effect of freeze-thaw on the shear strength becomes less and less. Therefore, the number of 10 freeze-thaw cycles can be used To evaluate the freeze-thaw resistance of the cement-based waterproof adhesive layer.

[0062] (2) Pull-out test results

[0063] Measure the tensile strength of composite drawing specimens of 50mm×50mm×50mm+cement concrete slab layer with different freeze-thaw cycles (0, 5, 10, 15, 20, 25 times) respectively. Four parallel test pieces are used for each number of freeze-thaw cycles. The results of the pull-out test are shown in Table 2.

[0064] Table 2 Drawing strength of specimens with different cycles

[0065]

[0066]

[0067] by figure 2 It can be seen that as the number of freeze-thaw cycles increases, the pull-out strength of the cement-based waterproof adhesive layer gradually decreases. From 0 freeze-thaw cycles to 10 freeze-thaw cycles, the pull-out strength decreases by 35.7%, and the rate of decrease is 0.04MPa /Time, from 10 freeze-thaw cycles to 25 freeze-thaw cycles, the tensile strength decreased by 20.8%, and the rate of decrease was 0.01MPa/time. This shows that the first 10 freeze-thaw cycles of the cement-based waterproof adhesive layer have a greater impact on its pull-out strength. After 10 freeze-thaw cycles, the effect of freeze-thaw on the pull-out strength becomes less and less. Therefore, the number of freeze-thaw cycles can be used To evaluate the freeze-thaw resistance of the cement-based waterproof adhesive layer.

[0068] In summary, it can be seen from the results of shear and pull-out tests that the cement-based waterproof adhesive layer adopts a freeze-thaw cycle method of freezing in the refrigerator at -18℃±2℃ for 4 hours and melting in water at 60℃±0.5℃ for 1 hour. The number of thawing cycles has a greater impact on its shear and drawing strength, and the strength decline rate is faster. After 10 freeze-thaw cycles, the strength declines more and more slowly. Therefore, it can be frozen in the refrigerator at -18℃±2℃ for 4 hours. Thaw in water at 60°C±0.5°C for 1 hour, freeze-thaw cycles 10 times, as a test method to evaluate the freeze-thaw resistance of the cement-based waterproof adhesive layer.

Example Embodiment

[0069] Example 2:

[0070] The difference between this embodiment and Embodiment 1 is only:

[0071] Step (7), put 20 shear test pieces and 20 drawing test pieces into the rubber test box respectively, add drinking water to make it cover the top surface of the test piece by 2mm, and then freeze it in the refrigerator at -18℃ for 16h , Within 10 minutes, put the specimens frozen for 16 hours into 25℃ water and thaw for 24 hours for one cycle.

[0072] The shear strength and pull-out strength of the specimens were measured, and the test results are shown in Table 3 and Table 4.

[0073] Table 3 Shear strength of the specimen after one freeze-thaw cycle

[0074]

[0075] Table 4 The pull-out strength of the specimen after one freeze-thaw cycle

[0076]

[0077] It can be seen from Table 3 and Table 4 that after one cycle of freezing and thawing in a refrigerator at -18°C for 16 hours and thawing in water at 25°C for 24 hours, the shear strength and pullout strength of the specimens decreased by 1.8 respectively. % And 2.7%, the drop rate is very small, indicating that this freeze-thaw cycle method and times have little effect on the tensile strength and shear strength of the cement-based waterproof bonding layer, and the tensile strength and shear strength are small Decline, sometimes due to instrument errors and operating errors, the test results are completely different.

[0078] Therefore, consider shortening the freezing and thawing time, increasing the number of freezing and thawing, changing the thawing temperature for the freezing and thawing cycle test. The selected freezing and thawing temperature is based on the two extreme temperatures that can occur in the actual road, and it is also the "Highway Engineering Cement and Cement Concrete The temperature used to evaluate the freeze-thaw resistance effect of cement concrete and asphalt mixture in the "Test Regulations" and "Test Regulations for Highway Engineering Asphalt and Asphalt Mixtures".

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

Description & Claims & Application Information

We can also present the details of the Description, Claims and Application information to help users get a comprehensive understanding of the technical details of the patent, such as background art, summary of invention, brief description of drawings, description of embodiments, and other original content. On the other hand, users can also determine the specific scope of protection of the technology through the list of claims; as well as understand the changes in the life cycle of the technology with the presentation of the patent timeline. Login to view more.

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

Classification and recommendation of technical efficacy words

Good economic and social benefits

Automatic sleep stage method based on electroencephalogram, heart rate variability and coherence between electroencephalogram and heart rate variability

ActiveCN103584840AImprove accuracy and simplicityGood economic and social benefitsSensorsMeasuring/recording heart/pulse ratePediatricsSleep Stages

Owner:TIANJIN UNIV

Test method for evaluating freezing and thawing resistance of cement-based waterproof bonding layer

A technology of waterproof adhesive layer and test method, which is applied in the direction of testing material strength by applying stable shear force, testing material strength and strength characteristics by applying stable tension/pressure, and achieving obvious economic and social benefits

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

Similar technology patents

Simple industrial production method for dendrobium candidum

Remote fault diagnosis system and method for concrete batching plants

Method for purifying powdered iron from steel-smelting sewage sludge coarse grain

Coal dressing collecting agent and preparing method thereof

Method for controlling stability of air-fuel ratio of gas cooker

Classification and recommendation of technical efficacy words

Automatic sleep stage method based on electroencephalogram, heart rate variability and coherence between electroencephalogram and heart rate variability

Wireless sensor network-based river basin pollution monitor system and method

Low grade tailing steel slag re-use method and slurry magnetic separation equipment

BIM technology-based project amount calculation method

Parking guidance system based on LBS (location based service)