Method of calculating the dosage of phase change coarse aggregate, method of manufacturing the same and thermoregulating pavement

Abstract

The present invention provides a method of calculating the dosage of phase change coarse aggregate, which comprises the steps of setting a regulatory temperature difference of a thermoregulating cement-stabilized layer, the regulatory temperature difference being the difference between the peak temperature of the thermoregulating cement-stabilized layer and the peak temperature of a conventional cement-stabilized layer, wherein the thermoregulating cement-stabilized layer is mixed with a phase change coarse aggregate, while the conventional cement-stabilized layer is not mixed with a phase change coarse aggregate; calculating a regulatory heat based on the regulatory temperature difference, wherein when a temperature change of the conventional cement-stabilized layer is the regulatory temperature difference, a heat change of the conventional cement-stabilized layer is the regulatory heat; and calculating a volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer based on the regulatory heat.

Claims

1. A method of calculating a dosage of phase change coarse aggregate, which comprises the steps of setting a regulatory temperature difference of a thermoregulating cement-stabilized layer, the regulatory temperature difference being the difference between the peak temperature of the thermoregulating cement-stabilized layer and the peak temperature of a conventional cement-stabilized layer, wherein the thermoregulating cement-stabilized layer is mixed with a phase change coarse aggregate, while the conventional cement-stabilized layer is not mixed with a phase change coarse aggregate; calculating a regulatory heat based on the regulatory temperature difference, wherein when a temperature change of the conventional cement-stabilized layer is the regulatory temperature difference, a heat change of the conventional cement-stabilized layer is the regulatory heat; and calculating a volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer based on the regulatory heat; after calculating a volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer, the method further comprises the step of calculating a mixing ratio of the phase change coarse aggregate in the thermoregulating cement-stabilized layer based on the volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer; calculating the mixing ratio n of the phase change coarse aggregate in the thermoregulating cement-stabilized layer by using Equation $n=\frac{V_3}{V_0^{}+V_2+V_3},$ where V.sub.2 is the volume occupied by the conventional coarse aggregate in the thermoregulating cement-stabilized layer and V.sub.20, V.sub.0 is the volume occupied by substances other than the conventional coarse aggregate and the phase change coarse aggregate in the thermoregulating cement-stabilized layer, and V.sub.3 is the volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer; calculating the regulatory heat by using Equation Q=c.sub.0.sub.0V.sub.0T+c.sub.1.sub.1V.sub.1T where T=T.sub.2T.sub.1, T is the regulatory temperature difference, T.sub.2 is the peak temperature of the thermoregulating cement-stabilized layer, T.sub.1 is the peak temperature of the conventional cement-stabilized layer, Q is the regulatory heat, c.sub.0 is the specific heat capacity of substances other than the conventional coarse aggregate in the conventional cement-stabilized layer, .sub.0 is the density of substances other than the conventional coarse aggregate in the conventional cement-stabilized layer, V.sub.0 is the volume of substances other than the conventional coarse aggregate in the conventional cement-stabilized layer, c is the specific heat capacity of the conventional coarse aggregate in the conventional cement-stabilized layer, .sub.1 is the density of the conventional coarse aggregate in the conventional cement-stabilized layer, and V.sub.1 is the volume of the conventional coarse aggregate in the conventional cement-stabilized layer; calculating the volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer by using Equation $V_3=\frac{Q}{H.Math.{}_3},$ where V.sub.3 is the volume occupied by the phase change coarse aggregate in the thermoregulating cement-stabilized layer, H is the latent heat of phase change of the phase change coarse aggregate, and .sub.3 is the density of the phase change coarse aggregate.

2. The method of calculating the dosage of phase change coarse aggregate according to claim 1, wherein before setting the regulatory temperature difference of the thermoregulating cement-stabilized layer, the method further comprises the step of calculating the peak temperature of the thermoregulating cement-stabilized layer based on the peak temperature of the conventional cement-stabilized layer.

3. The method of calculating the dosage of phase change coarse aggregate according to claim 2, wherein the peak temperature of the thermoregulating cement-stabilized layer is calculated by using Equation $T_2=\sqrt{\frac{t_2-t_1}{t_2^{}-t_1^{}}}.Math.T_1,$ where T.sub.2 is the peak temperature of the thermoregulating cement-stabilized layer, T.sub.1 is the peak temperature of the conventional cement-stabilized layer, t.sub.1 is an exothermic onset time of the conventional cement-stabilized layer, t.sub.2 is an exothermic termination time of the conventional cement-stabilized layer, t.sub.1 is an exothermic onset time of the thermoregulating cement-stabilized layer, and t.sub.2 is an exothermic termination time of the thermoregulating cement-stabilized layer.

4. A method of manufacturing a phase change coarse aggregate, wherein the dosage of phase change coarse aggregate is calculated using the method of calculating the dosage of phase change coarse aggregate according to claim 1, and the manufacturing method comprises the steps of fabricating a metal shell; drilling a hole in the metal shell; injecting a phase change material into the metal shell through the hole in the metal shell; and sealing the hole of the metal shell.

5. A thermoregulating pavement, wherein the dosage of phase change coarse aggregate in the thermoregulating pavement is calculated using the method of calculating the dosage of phase change coarse aggregate according to claim 1, and the thermoregulating pavement comprises a surface layer, a thermoregulating cement-stabilized layer, and a subbase layer provided in sequence.

6. The thermoregulating pavement according to claim 5, wherein the phase change coarse aggregate comprises a metal shell and a phase change material provided in the metal shell.

7. The thermoregulating pavement according to claim 6, wherein the phase change material satisfies a supercooling degree of less than or equal to 5.0 C., a phase transition temperature of greater than or equal to 10.0 C., and a latent heat of greater than or equal to 120.0 J/g.

8. The thermoregulating pavement according to claim 5, wherein the phase change coarse aggregate has an irregular shape to allow the phase change coarse aggregate to interlock with other materials in the thermoregulating cement-stabilized layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The following drawings are provided for illustrative purposes only and merely depict exemplary embodiments of the disclosure. These drawings are provided to facilitate the reader's understanding of the disclosure and should not be considered as limiting to the breadth, scope, or applicability of the disclosure. It should be noted that these drawings are not necessarily drawn to scale for clarity and ease of illustration.

(2) The figure is a structural diagram of a thermoregulating pavement according to the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

(3) The invention will be described in more detail below with reference to specific embodiments. However, the embodiments described below are merely illustrative and should not be construed as limiting the scope of the foregoing subject matter of the invention, and all technologies implemented according to the contents of the invention fall within the scope of the invention.

(4) Unless otherwise indicated, in the descriptions of specific embodiments of the invention, terms such as upper, lower, left, right, center, inner, outer, etc., which indicate orientation or positional relationship, are all expressions based on the orientation or positional relationship shown in the accompanying drawings or the orientation or positional relationship with which the product/equipment/device of the invention is commonly used. These terms of orientation or positional relationship are used only for the purpose of facilitating the description of the technical solutions of the invention or simplifying the description of the specific embodiments to facilitate a quick understanding of the technical solutions of the invention by those skilled in the art. Accordingly, they do not indicate or imply that a particular device/component/element must have a particular orientation or be constructed and operated in a particular positional relationship and should therefore not be construed as a limitation of the invention.

(5) Furthermore, whenever the terms horizontal, vertical, overhanging, parallel, etc. are used, they do not imply that the corresponding device/component/element must be absolutely horizontal, vertical, overhanging or parallel, but may be slightly inclined or deviated. For example, horizontal merely implies that its orientation is more horizontal than vertical and does not mean that the structure must be completely horizontal, but may be slightly inclined. Alternatively, it can simply be understood that when the corresponding device/component/element is set in a direction such as horizontal, vertical, overhanging, parallel, etc., it can be set with an error/deviation of +10%, preferably within +8%, more preferably within +6%, even more preferably within +5%, and most preferably within +4% with respect to the corresponding directional setting. As long as the corresponding device/component/element is still able to perform its function in the solutions of the invention within these error/deviation ranges.

(6) Furthermore, whenever expressions such as first, second, third, etc. are used in the terms, they are merely descriptions used to distinguish the same or similar components and should not be construed as emphasizing or implying the relative importance of any particular element.

(7) Furthermore, in the descriptions of embodiments of the invention, several, a plurality of or many means at least 2. This can be any of 2, 3, 4, 5, 6, 7, 8, 9, or even more than 9.

(8) Furthermore, in the description of technical solutions of the invention, unless otherwise expressly indicated/defined/restricted, wherever the terms provide, install, interconnect, connect, mix, lay and arrange are used, they should be interpreted in a broad sense, e.g., they may be a fixed connection, a removable connection, or an integral connection. It may also include welding, riveting, bolting, threading, and other means of connection commonly used in the field. This connection may be a mechanical connection, an electrical connection, or a telecommunications connection. It may also be a direct connection, an indirect connection through an intermediate medium, or an internal connection of two elements.

(9) In the related art, phase change material has been added to the pavement, and the phase transition of the phase change material has been used to store a large amount of heat, thereby preventing heat transfer downwards and reducing the warming rate of the pavement. However, the phase change material is usually provided in the surface layer of the pavement, which is susceptible to abrasion and damage during long-term use, resulting in a reduction in the energy storage performance of the phase change material. In addition, the dosage accuracy cannot be guaranteed because the dosage of the phase change material is usually controlled by experience. Therefore, the technical solutions of the present application have been developed to solve such problems, which are described below with reference to the figure.

(10) One aspect of the invention provides a method of calculating the dosage of phase change coarse aggregate 30 in a thermoregulating cement-stabilized layer, wherein a thermoregulating pavement typically comprises a surface layer 10, a thermoregulating cement-stabilized layer 20, and a subbase layer 50 provided in sequence, and the calculation method may comprise the following steps.

(11) Firstly, a regulatory temperature difference 4T of the thermoregulating cement-stabilized layer 20 in the thermoregulating pavement is set, wherein the regulatory temperature difference T is the difference between the peak temperature T.sub.2 of the thermoregulating cement-stabilized layer 20 and the peak temperature Ty of the conventional cement-stabilized layer, in which the thermoregulating cement-stabilized layer 20 is mixed with a phase change coarse aggregate 30 and the conventional cement-stabilized layer is not mixed with a phase change coarse aggregate 30. That is, the thermoregulating cement-stabilized layer 20 can be formed by mixing a phase change coarse aggregate 30 into the conventional cement-stabilized layer, wherein the phase change coarse aggregate 30 contains a phase change material. As a result, the phase transition of the phase change material stores a large amount of heat, thereby allowing the peak temperature of the cement-stabilized layer to be reduced from T.sub.1 to T.sub.2.

(12) Then, a regulatory heat Q is calculated based on the regulatory temperature difference, wherein when the temperature of the conventional cement-stabilized layer is elevated by the regulatory temperature difference T, then the heat absorbed by the conventional cement-stabilized layer is the regulatory heat Q, i.e., the heat that can be absorbed by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20 when the temperature of the thermoregulating cement-stabilized layer 20 is elevated by the regulatory temperature difference T.

(13) Finally, a volume V.sub.3 occupied by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20 is calculated based on the regulatory heat Q.

(14) In the present invention, the phase change coarse aggregate 30 is mixed for the purpose of reducing the peak temperature of the cement-stabilized layer, such as reducing the peak temperature of the cement-stabilized layer from T.sub.1 to T.sub.2, where T.sub.1 can be construed as the peak temperature of the conventional cement-stabilized layer and T.sub.2 can be construed as the peak temperature of thermoregulating cement-stabilized layer 20. Based on this, first the regulatory temperature difference T=T.sub.2T.sub.1 is calculated, then the regulatory heat Q is calculated, and finally, the volume V.sub.3 occupied by the phase change coarse aggregate 30 in the regulated temperature stabilizing layer 20 is calculated.

(15) As a result, since the phase change coarse aggregate 30 is mixed into the thermoregulating cement-stabilized layer 20 instead of the surface layer 10, the phase change coarse aggregate 30 can be protected from abrasion and damage, which in turn ensures the energy storage capability of the phase change coarse aggregate 30. On the other hand, if the phase change coarse aggregate 30 is mixed in too small of an amount, the expected regulatory temperature difference will not be achieved, and the peak temperature of the cement-stabilized layer will not be reduced to the expected value, thus failing to provide sufficient protection to the pavement. Especially for the permafrost subgrade, the pavement will experience subgrade damage such as thermal thawing and settlement if the cement-stabilized layer fails to achieve the expected regulatory temperature difference. In contrast, if the phase change coarse aggregate 30 is mixed in an excessive amount, the investment cost of the pavement will be increased and will result in wasted phase change material. Therefore, the dosage of phase change coarse aggregate 30 can be accurately controlled while effectively reducing the peak temperature by the above calculation. Especially for the permafrost subgrade, the material cost of phase change coarse aggregate 30 can be reduced while effectively reducing the peak temperature. Furthermore, in the process of pavement construction, the expected protection effect can be achieved while reducing the investment cost of the pavement, which is economically beneficial. Furthermore, the application scenario of the thermoregulating pavement according to the present invention is usually in permafrost areas, where the metal shell of the phase change coarse aggregate has good thermal conductivity, which enables the phase change coarse aggregate 30 to perform the function of phase change energy storage quickly and fully, thus preventing the heat from being transferred downward and protecting the permafrost.

(16) In a preferred embodiment of the invention, before setting the regulatory temperature difference of thermoregulating cement-stabilized layer 20, the method further comprises a step of calculating the peak temperature T.sub.2 of thermoregulating cement-stabilized layer 20 based on the peak temperature Ty of the conventional cement-stabilized layer, wherein the peak temperature Ty of the conventional cement-stabilized layer can be obtained from an actual measurement.

(17) In a preferred embodiment of the invention, the peak temperature of thermoregulating cement-stabilized layer 20 is calculated by using Equation

(18) $T_2=\sqrt{\frac{t_2-t_1}{t_2^{}-t_1^{}}}.Math.T_1;$
where T.sub.2 is the peak temperature of thermoregulating cement-stabilized layer 20, T, is the peak temperature of the conventional cement-stabilized layer, t.sub.1 is the exothermic onset time of the conventional cement-stabilized layer, t.sub.2 is the exothermic termination time of the conventional cement-stabilized layer, t.sub.1 is the exothermic onset time of thermoregulating cement-stabilized layer 20, and t.sub.2 is the exothermic termination time of thermoregulating cement-stabilized layer 20. The exothermic onset time can be construed as the timing at which the phase change material starts performing its function when the external temperature is higher than the phase transition temperature of the phase change material. The exothermic termination time can be construed as the timing at which the phase change material stops performing its function when the external temperature is lower than the phase transition temperature of the phase change material. In the specific calculation process, T.sub.1, t.sub.1, t.sub.2, t.sub.1 and t.sub.2 are determined by a specific measurement. Among them, tr=t.sub.1 can be set in order to facilitate the calculation.

(19) In a preferred embodiment of the invention, after calculating the volume V.sub.3 occupied by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20, the method further comprises a step of calculating the mixing ratio n of the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20 based on the volume V.sub.3 occupied by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20.

(20) In a preferred embodiment of the invention, the mixing ratio n of the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20 is calculated by using Equation

(21) $n=\frac{V_3}{V_0^{}+V_2+V_3},$
where n is the mixing ratio of phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20, V.sub.2 is the volume occupied by the conventional coarse aggregate 40 in the thermoregulating cement-stabilized layer 20 and V.sub.20, wherein V.sub.2=0 means that only phase change coarse aggregate 30 is provided in the thermoregulating cement-stabilized layer 20, V.sub.2>0 means that both the phase change coarse aggregate 30 and the conventional coarse aggregate 40 are provided in the thermoregulating cement-stabilized layer 20, V.sub.0 is the volume occupied by substances other than the conventional coarse aggregate 40 and the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20, and V.sub.3 is the volume occupied by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20.

(22) Furthermore, the mixing ratio n is usually a percentage, so the above equation is also denoted as

(23) $n=\frac{V_3}{V_0^{}+V_2+V_3}100\%.$

(24) In a preferred embodiment of the invention, the regulatory heat is calculated by using Equation Q=C.sub.0.sub.0V.sub.0T+c.sub.1.sub.1T, where T=T.sub.2T.sub.1, T is the regulatory temperature difference, T.sub.2 is the peak temperature of thermoregulating cement-stabilized layer 20, T.sub.1 is the peak temperature of the conventional cement-stabilized layer, Q is the regulatory heat, c.sub.0 is the specific heat capacity of substances other than the conventional coarse aggregate 40 in the conventional cement-stabilized layer, .sub.0 is the density of substances other than the conventional coarse aggregate 40 in the conventional cement-stabilized layer, V.sub.0 is the volume of substances other than the conventional coarse aggregate 40 in the conventional cement-stabilized layer, c/is the specific heat capacity of the conventional coarse aggregate 40 in the conventional cement-stabilized layer, .sub.1 is the density of the conventional coarse aggregate 40 in the conventional cement-stabilized layer, and V.sub.1 is the volume of the conventional coarse aggregate 40 in the conventional cement-stabilized layer.

(25) Furthermore, the conventional cement-stabilized layer and the thermoregulating cement-stabilized layer 20 satisfy Equations V.sub.0=V.sub.0 and V.sub.1=V.sub.2+V.sub.3. That is, the mixing of the phase change coarse aggregate 30 is conducted by an equal volume replacement method. Specifically, the volume of the conventional coarse aggregate 40 in the conventional cement-stabilized layer is V.sub.1, and the thermoregulating cement-stabilized layer 20 is formed by replacing the conventional coarse aggregate 40 in the conventional cement-stabilized layer with an equal volume of the phase change coarse aggregate 30 having a volume of V.sub.3, so that the volume of the conventional coarse aggregate in the thermoregulating cement-stabilized layer 20 is reduced to V.sub.2, i.e., V.sub.1=V.sub.2+V.sub.3, while the volume of the remaining material is unchanged, i.e., V.sub.0=V.sub.0.

(26) In a preferred embodiment of the invention, the volume occupied by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20 is calculated by using Equation

(27) $V_3=\frac{Q}{H.Math.{}_3},$
where V.sub.3 is the volume occupied by the phase change coarse aggregate 30 in the thermoregulating cement-stabilized layer 20, H is the latent heat of phase change coarse aggregate 30, and .sub.3 is the density of phase change coarse aggregate 30.

(28) Another aspect of the invention provides a method of manufacturing the phase change coarse aggregate 30 for use in the above-described dosage calculation method, and the manufacturing method comprises the steps of fabricating a metal shell, the shell being irregularly shaped to allow the phase change coarse aggregates 30 to be interlocked with each other, thereby ensuring the strength of the pavement structure; drilling a hole in the metal shell; injecting a phase change material into the metal shell through the hole in the metal shell; and sealing the hole of the metal shell by welding or the like.

(29) Yet another aspect of the invention provides a thermoregulating pavement which employs the above-described method. The thermoregulating pavement is a composite pavement structure, and more particularly, the thermoregulating pavement includes a surface layer 10, a thermoregulating cement-stabilized layer 20, and a subbase layer 50 provided in sequence. The thermoregulating cement-stabilized layer 20 is provided with a phase change coarse aggregate 30, which can reduce the peak temperature of the thermoregulating pavement, postpone and delay the time at which the thermoregulating cement-stabilized layer 20 reaches the peak temperature, thereby achieving the effect of protecting the pavement. Meanwhile, since the phase change coarse aggregate 30 is provided away from the surface layer 10, abrasion damage to the phase change coarse aggregate 30 is reduced and the energy storage performance of the phase change coarse aggregate 30 is ensured.

(30) In a preferred embodiment of the invention, the phase change coarse aggregate 30 may include a metal shell and a phase change material provided in the metal shell. Wherein the phase change material can be composed of inorganic, organic or composite materials, such as paraffin, polyols, fatty acids or the like, and the phase change material satisfies a supercooling degree of less than or equal to 5.0 C., a phase transition temperature of greater than or equal to 10.0 C., and a latent heat of greater than or equal to 120.0 J/g, so as to effectively utilize the phase change energy storage ability of the phase change material and then fully protect the permafrost when the pavement according to the present invention is applied in permafrost areas. The metal shell can be composed of materials such as steel and has a particle size of 0.075 mm to 53.0 mm. The metal shell can be provided to encapsulate and protect the phase change material therein, and on the other hand, the good thermal conductivity of the metal can be utilized to allow the phase change material to realize its effects.

(31) In a preferred embodiment of the invention, the thermoregulating cement-stabilized layer 20 is mixed with a conventional coarse aggregate 40, the conventional coarse aggregate 40 being composed of natural rock, pebbles or mine waste rock or the like, so as to be used as a framework for the concrete in the pavement and to improve the structural stability of the concrete in the pavement.

(32) In a preferred embodiment of the invention, the phase change coarse aggregate 30 has an irregular shape and a rough surface, and as compared to a regular shape such as a circle or a rectangle, the irregular and rough shape design of the phase change coarse aggregate 30 allows the phase change coarse aggregate 30 to interlock with other materials in the thermoregulating cement-stabilized layer 20, so as to generate a larger internal frictional resistance to ensure that the structure of the thermoregulating cement-stabilized layer 20 is fixed and to ensure that the thermoregulating pavement is structurally strong.

(33) All the above are only some of the preferred embodiments of the invention and are not intended to limit the invention. The invention may also have a variety of other embodiments, and without departing from the spirit and substance of the invention, a person skilled in the art may make various changes and modifications in accordance with the invention, but such changes and modifications shall fall within the protection scope of the invention.