Design method for interlayer shear strength of waterproof bonding layer of composite pavement

Abstract

The invention provides an interlayer shear strength design method for a waterproof bonding layer of a composite pavement. The interlayer shear strength design method comprises the following steps: S1, drawing up design parameters of the waterproof bonding layer of the composite pavement; s2, calculating the embedding and extruding strength of the waterproof bonding layer; s3, calculating the friction resistance strength of the waterproof bonding layer; s4, calculating an interlocking-friction coupling contact number; s5, calculating a standard value of the shear strength of the waterproof bonding layer; s6, calculating an aggregate spreading amount correction coefficient; s7, calculating a temperature correction coefficient; and S8, calculating a design value of the shear strength of the waterproof bonding layer. According to the method, a quantitative evaluation method is provided for determining the shear strength which can be achieved by different combinations of waterproof bonding layer treatment measures, and the design and construction of the waterproof bonding layer can be effectively guided; the method is of great significance in guaranteeing the shear strength of the waterproof bonding layer, reducing pavement diseases and improving the safety, reliability and durability of the composite pavement.

Description

Technical Field

[0001] The present application relates to the field of roads, and in particular to a method for designing the interlayer shear strength of a composite pavement waterproof bonding layer. Background Art

[0002] In composite pavement engineering, the interlayer interface between the asphalt upper layer and the cement concrete lower layer is the weak surface of the composite pavement structure. The shear resistance of this interface depends on the shear strength of the waterproof bonding layer. When the shear strength is not enough to resist the horizontal shear force generated by the vehicle, the upper and lower layers will have relative displacement and shear failure, and then form diseases such as push and embrace on the asphalt pavement. In order to ensure the integrity of the pavement structure, a waterproof bonding layer is often used to strengthen the interlayer bonding ability between the asphalt upper layer and the cement concrete lower layer. The shear strength of the waterproof bonding layer can improve the overall stress state of the pavement. Therefore, the reasonable design of the waterproof bonding layer based on the shear strength is the key to ensure the overall performance of the composite pavement.

[0003] The specific measures for the waterproof bonding layer mainly include: treatment of the top surface of the cement concrete layer, selection of aggregate particle size and spreading amount, and selection of bonding material type. The above measures are also the main influencing factors of the shear strength of the waterproof bonding layer. At present, the design of the waterproof bonding layer mainly relies on the empirical method. The shear strength that can be achieved by the waterproof bonding layer formed by the combination of different measures cannot be determined in advance during the design stage, and the corresponding combination of measures cannot be selected in advance. Therefore, there is a certain degree of blindness in the actual implementation of the waterproof bonding layer. In pavement engineering, unreasonable design often causes insufficient actual shear strength of the waterproof bonding layer, which causes pavement diseases. The waterproof bonding layer urgently needs a shear strength design method to quantitatively evaluate the shear strength of the waterproof bonding layer formed by the combination of different measures in advance, so as to ensure the bearing capacity of the composite pavement. Summary of the invention

[0004] The shear strength of the waterproof bonding layer mainly comes from the interlocking effect, friction and bonding effect of aggregates and bonding materials. The shear strength of the waterproof bonding layer has an obvious corresponding rule with the structural depth after the top surface of the cement concrete layer is treated, the aggregate particle size, the amount of aggregate spread and the type of bonding material. Based on the above rules, the present application provides a method for designing the interlayer shear strength of the waterproof bonding layer of a composite pavement, which can effectively solve the problem of the lack of design methods to guide the shear strength of the waterproof bonding layer. It can effectively guide the design and construction of different measures for the waterproof bonding layer, match the corresponding combination of measures for the different shear strengths required for the pavement, ensure the bearing performance of the composite pavement, improve the durability of the pavement, and ensure driving safety. It is of great significance to ensure the safety, reliability and durability of the composite pavement.

[0005] The technical solution of this application is:

[0006] A method for designing the interlayer shear strength of a composite pavement waterproof bonding layer comprises the following steps:

[0007] S1, formulate design parameters of composite pavement waterproof bonding layer;

[0008] S2, calculate the embedding strength of the waterproof bonding layer;

[0009] S3, calculate the friction strength of the waterproof bonding layer;

[0010] S4, calculate the squeeze-friction coupling coefficient;

[0011] S5, calculate the standard value of shear strength of waterproof bonding layer;

[0012] S6, calculate the correction factor of aggregate spreading amount;

[0013] S7, calculate the temperature correction coefficient;

[0014] S8. Calculate the design value of shear strength of the waterproof bonding layer.

[0015] As a technical solution of the present application, in step S1, the design parameters of the composite pavement waterproof bonding layer include: surface structural depth of the lower layer of cement concrete, aggregate particle size, aggregate spreading amount, bonding material type, and temperature.

[0016] As a technical solution of the present application, in step S2, the calculation formula of the embedding strength of the waterproof adhesive layer is as follows:

[0017] τ i =0.2537ln TD+0.8166;

[0018] Where: τ i is the embedding strength of the waterproof bonding layer, MPa; TD is the surface structural depth of the lower layer of cement concrete, mm.

[0019] As a technical solution of the present application, in step S3, the friction strength calculation formula of the waterproof adhesive layer is as follows:

[0020]

[0021] Where: τ f is the friction strength of the waterproof bonding layer, MPa; p s is the aggregate particle size, mm.

[0022] As a technical solution of the present application, in step S4, the calculation formula of the squeeze-friction coupling coefficient is as follows:

[0023]

[0024] Where: ρ is the squeeze-friction coupling coefficient; TD is the surface structural depth of the cement concrete layer below, mm; p s is the aggregate particle size.

[0025] As a technical solution of the present application, in step S5, the calculation formula of the standard value of the shear strength of the waterproof adhesive layer is as follows:

[0026] τ s =ρτ i +(1-ρ)τ f ;

[0027] Where: τ s is the standard value of shear strength of waterproof bonding layer, MPa; ρ is the squeeze-friction coupling coefficient; τ f Friction strength of waterproof bonding layer, MPa.

[0028] As a technical solution of the present application, in step S6, the aggregate spreading amount correction coefficient calculation formula is as follows:

[0029]

[0030] Where: is the aggregate spreading amount correction coefficient; A is the aggregate spreading amount, the unit is %.

[0031] As a technical solution of the present application, in step S7, the temperature correction coefficient calculation formula is as follows:

[0032]

[0033] Where: is the temperature correction coefficient; T is the ambient temperature, in °C.

[0034] As a technical solution of the present application, in step S8, the calculation formula of the design value of the shear strength of the waterproof bonding layer is as follows:

[0035]

[0036] Where: τ D is the design value of the shear strength of the waterproof bonding layer, MPa; η is the bonding material type coefficient, where η is 1.0 if the bonding material type is ordinary hot asphalt, η is 1.1 if the bonding material type is SBS modified asphalt, and η is 1.15 if the bonding material type is rubber modified asphalt; is the correction factor for aggregate spreading amount; is the temperature correction coefficient; τ s It is the standard value of shear strength of waterproof bonding layer.

[0037] Beneficial effects of this application:

[0038] The present application provides a method for designing the shear strength between layers of a composite pavement waterproof bonding layer, which provides a quantitative evaluation method for determining the shear strength that can be achieved by different combinations of waterproof bonding layer treatment measures, and designs specific measures such as structural depth, aggregate particle size, aggregate spreading amount, and bonding material type in advance based on the shear strength required between layers of the composite pavement, effectively guiding the design and construction of the waterproof bonding layer. This method is of great significance for ensuring the shear strength of the waterproof bonding layer, reducing pavement diseases, and improving the safety, reliability, and durability of the composite pavement. It can effectively solve the problem of lack of design methods to guide the shear strength of the waterproof bonding layer. It can effectively guide the design and construction of different measures for the waterproof bonding layer, match the corresponding combination of measures for the different shear strengths required for the pavement, ensure the bearing performance of the composite pavement, improve the durability of the pavement, and ensure driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the implementation methods of the present application, the drawings required for use in the implementation methods will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A schematic flow chart of a method for designing the interlayer shear strength of a composite pavement waterproof bonding layer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0043] Example:

[0044] The shear strength of the waterproof bonding layer mainly comes from the interlocking effect, friction and bonding effect of aggregates and binders. The shear strength of the waterproof bonding layer has a clear corresponding rule with the structural depth after the top surface of the cement concrete layer is treated, the aggregate particle size, the amount of aggregate spread and the type of binder.

[0045] Based on the above rules, please refer to Figure 1 In the embodiment of the present application, a method for designing the interlayer shear strength of a composite pavement waterproof bonding layer is provided. First, the design parameters of the composite pavement waterproof bonding layer are formulated, and then the embedding strength of the waterproof bonding layer and the friction strength of the waterproof bonding layer are calculated, and then the embedding-friction coupling coefficient is calculated, and then the standard value of the shear strength of the waterproof bonding layer is calculated, and then the correction coefficient of the aggregate spreading amount and the temperature correction coefficient are calculated, and finally the design value of the shear strength of the waterproof bonding layer is calculated; specifically, it is applied to a newly built composite pavement project in a certain area, and mainly includes the following steps:

[0046] S1, propose the design parameters of waterproof bonding layer:

[0047] A new composite pavement project in a certain area uses a waterproof bonding layer at the interface between layers; the surface structure depth of the cement concrete lower layer is 0.9mm, the aggregate particle size is 9.5mm, the aggregate spreading amount is 55%, the bonding material type is SBS modified asphalt, and the ambient temperature is 35℃;

[0048] S2, calculate the embedding strength of the waterproof bonding layer:

[0049] τ i =0.2537ln TD+0.8166=0.2537×ln0.9+0.8166=0.790MPa;

[0050] S3, calculate the friction strength of the waterproof bonding layer:

[0051]

[0052] Step S4: Calculate the squeeze-friction coupling coefficient

[0053]

[0054] S5, calculate the standard value of shear strength of waterproof bonding layer:

[0055] τ s =ρτ i +(1-ρ)τ f =0.830×0.790+(1-0.830)×0.820=0.795MPa;

[0056] S6, calculate the aggregate spreading correction factor:

[0057]

[0058] S7, calculate the temperature correction coefficient:

[0059]

[0060] S8, calculate the design value of shear strength of waterproof bonding layer:

[0061]

[0062] The design is now complete.

[0063] In summary, the shear strength design method for the composite pavement waterproof bonding layer provided in this application provides a quantitative evaluation method for determining the shear strength that can be achieved by different combinations of waterproof bonding layer treatment measures. Based on the required shear strength between the composite pavement layers, the structural depth, aggregate particle size, aggregate spreading amount, and bonding material type are designed in advance to effectively guide the design and construction of the waterproof bonding layer. This method is of great significance for ensuring the shear strength of the waterproof bonding layer, reducing pavement diseases, and improving the safety, reliability, and durability of the composite pavement. It can effectively solve the problem of the lack of design methods to guide the shear strength of the waterproof bonding layer. It can effectively guide the design and construction of different measures for the waterproof bonding layer, match the corresponding combination of measures for the different shear strengths required for the pavement, ensure the bearing performance of the composite pavement, improve the durability of the pavement, and ensure driving safety.

[0064] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for designing the interlayer shear strength of a composite pavement waterproof bonding layer, characterized in that: The following steps are involved: S1, formulate design parameters of composite pavement waterproof bonding layer; S2, calculate the embedding strength of the waterproof bonding layer; S3, calculate the friction strength of the waterproof bonding layer; S4, calculate the squeeze-friction coupling coefficient; S5, calculate the standard value of shear strength of waterproof bonding layer; S6, calculate the correction factor of aggregate spreading amount; S7, calculate the temperature correction coefficient; S8, calculate the design value of shear strength of the waterproof bonding layer.

2. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S1, the design parameters of the composite pavement waterproof bonding layer include: surface structural depth of the cement concrete lower layer, aggregate particle size, aggregate spreading amount, bonding material type, and temperature.

3. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S2, the waterproof adhesive layer embedding strength calculation formula is as follows: t i =0.2537ln TD+0.8166; Where: τ i is the embedding strength of the waterproof bonding layer, MPa; TD is the surface structural depth of the lower layer of cement concrete, mm.

4. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S3, the friction strength calculation formula of the waterproof bonding layer is as follows: Where: τ f is the friction strength of the waterproof bonding layer, MPa; p s is the aggregate particle size, mm.

5. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S4, the squeeze-friction coupling coefficient is calculated as follows: Where: ρ is the squeeze-friction coupling coefficient; TD is the surface structural depth of the cement concrete layer below, mm; p s is the aggregate particle size.

6. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S5, the calculation formula of the standard value of the shear strength of the waterproof bonding layer is as follows: t s =rt i +(1-p)t f ; Where: τ s is the standard value of shear strength of waterproof bonding layer, MPa; ρ is the squeeze-friction coupling coefficient; τ f Friction strength of waterproof bonding layer, MPa.

7. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S6, the calculation formula of the aggregate spreading amount correction coefficient is as follows: Where: is the aggregate spreading amount correction coefficient; A is the aggregate spreading amount, the unit is %.

8. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S7, the temperature correction coefficient is calculated as follows: Where: is the temperature correction coefficient; T is the ambient temperature, in °C.

9. The method for designing interlayer shear strength of a composite pavement waterproof bonding layer according to claim 1, characterized in that: In step S8, the calculation formula of the design value of the shear strength of the waterproof bonding layer is as follows: Where: τ D is the design value of shear strength of waterproof bonding layer, MPa; η is the binder type coefficient, where η is 1.0 if the binder type is ordinary hot asphalt, η is 1.1 if the binder type is SBS modified asphalt, and η is 1.15 if the binder type is rubber modified asphalt; is the correction factor for aggregate spreading amount; is the temperature correction coefficient; η is the standard value of the shear strength of the waterproof bonding layer.

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