A method for controlling the temperature of raw materials for concrete construction in winter

Abstract

The application discloses a concrete winter construction raw material temperature control method, and relates to the technical field of building, and comprises the following steps: establishing a first functional relationship between the total energy required for heating raw materials and the temperature of each raw material; establishing a second functional relationship between the concrete machine temperature and the temperature of each raw material; obtaining the actual minimum machine temperature of concrete according to the machine temperature specification value, the mold temperature specification value and the pouring completion specification value; and solving the temperature of each raw material when the total energy required for heating raw materials is at the minimum value according to the second functional relationship, the actual minimum machine temperature of concrete and the temperature requirement of raw materials. The application can obtain the control temperature of each raw material by solving the minimum value of the total energy required for heating raw materials under the second functional relationship, the actual minimum machine temperature of concrete and the temperature requirement of raw materials, realizes energy saving and emission reduction, and reduces energy waste.

Description

Technical Field

[0001] This application relates to the field of building technology, and in particular to a method for controlling the temperature of raw materials used in winter concrete construction. Background Technology

[0002] When the average daily outdoor temperature is below 5℃ for three consecutive days or the minimum temperature is below 0℃, concrete construction should be carried out in accordance with winter construction procedures. In addition to meeting the general requirements for concrete construction, winter concrete construction should also ensure that the temperatures of raw materials, discharge temperature, placement temperature, and curing temperature meet the specifications.

[0003] In high-altitude and frigid regions, due to the long winter, concrete construction inevitably falls into the winter construction period. Traditional winter construction methods rely on experience to heat and insulate raw materials, and measure the temperature at each construction stage to ensure compliance with specifications. While this approach meets the requirements for winter concrete construction, it often involves excessive heating and insulation measures, resulting in significant energy waste. Summary of the Invention

[0004] This application provides a method for controlling the temperature of raw materials during winter concrete construction to solve the problem of excessive energy waste in existing methods.

[0005] Firstly, this application provides a method for controlling the temperature of raw materials used in winter concrete construction, comprising the following steps:

[0006] Establish the first functional relationship between the total energy required to heat the raw materials and the temperature of each raw material;

[0007] Establish a second functional relationship between the concrete discharge temperature and the temperatures of each raw material;

[0008] Based on the specified values ​​for discharge temperature, pouring temperature, and pouring completion temperature, the actual minimum discharge temperature of the concrete is obtained.

[0009] Based on the second functional relationship, the actual minimum discharge temperature of concrete, and the temperature requirements of raw materials, calculate the temperature of each raw material when the total energy required to heat the raw materials is minimized in the first functional relationship.

[0010] This application establishes a second functional relationship between the concrete discharge temperature and the temperatures of various raw materials. Under the premise of meeting the specified discharge temperature, formwork temperature, and final pouring temperature, the actual minimum concrete discharge temperature is obtained. Based on the second functional relationship, the actual minimum concrete discharge temperature, and the temperature requirements of the raw materials, the temperature of each raw material is calculated to minimize the total energy required to heat them in the first functional relationship. By controlling the temperature of each raw material, the energy required to heat it can be minimized, achieving energy conservation and environmental protection, and reducing energy waste. This ensures that the concrete discharge temperature, formwork temperature, and final pouring temperature meet the specifications while minimizing the heat required to heat the raw materials.

[0011] In some embodiments, the raw materials include admixtures, cement, sand, gravel, and water. Temperature variations in these raw materials significantly affect energy consumption; establishing a relationship between these raw materials and total energy can improve the accuracy of energy control.

[0012] In some embodiments, the construction ambient temperature is -20℃ to 5℃. Typically, a construction environment is defined as an outdoor daily average temperature below 5℃ for three consecutive days or a minimum temperature below 0℃. Energy loss is more significant in winter construction environments. Therefore, within the aforementioned construction temperature range, the energy-saving effect is more significant.

[0013] In some embodiments, the first functional relationship includes:

[0014] Q = (T) s -T h )q s +(T ce -T h )q ce +(T sa -T h )q sa +(T g -T h )q g +(T w -T h )q w +(T p -T h )q p ;

[0015] Where: q s The amount of heat required to raise the temperature of the enclosed space of the admixture tank by 1°C, for a given silo and a given admixture, is q. s It is a fixed value;

[0016] q ce q represents the amount of heat required to raise the temperature of the enclosed space of a cement silo by 1°C, for a given silo and a given amount of cement.ce It is a fixed value;

[0017] q sa Let q be the amount of heat required to raise the temperature of the enclosed space of a sand silo by 1°C, for a given silo and a given amount of sand. sa It is a fixed value;

[0018] q g Let q be the amount of heat required to raise the temperature of the enclosed space of a gravel silo by 1°C, for a given silo and a given amount of gravel. g It is a fixed value;

[0019] q w Let q be the amount of heat required to heat water by 1°C. w It is a fixed value;

[0020] q p q represents the amount of heat required to raise the temperature of the mixer shed by 1°C, for a given construction environment. p It is a fixed value;

[0021] T h The ambient temperature during winter construction can be determined through measurement.

[0022] T s The temperature of the admixture is an unknown quantity, which can be confirmed by measuring with a temperature sensor.

[0023] T ce The temperature of the cement is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0024] T sa The temperature of the sand is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0025] T g The temperature of the stone is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0026] T w The temperature of the water is an unknown quantity that can be measured and confirmed using a temperature sensor.

[0027] T p The temperature of the mixer shed is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0028] It should be noted that, since the temperature of the raw materials is usually not lower than the temperature of the construction environment, therefore, T s The final temperature that the admixture needs to reach; T ce The final temperature that the cement needs to reach; T sa The final temperature that the sand needs to reach; T g The temperature that the stones ultimately need to reach; T wThe final temperature that the water needs to reach; T p This refers to the final temperature that the mixing plant shed needs to reach. Generally, sand and gravel silos are fully enclosed with insulated panels, water is stored in sealed tanks, cement and admixture powder silos are fully enclosed with insulated panels, and the mixer is fully enclosed with insulated panels. Heating measures typically include using underfloor heating, heaters, oil heaters, etc., to heat the enclosed spaces of sand and gravel silos, powder silos, and mixers, and using heating rods to heat the water.

[0029] In some embodiments, the second functional relationship includes:

[0030] T 出 =a1T s +a2T ce +a3T sa +a4T g +a5T w +a6T p +b1;

[0031] in:

[0032] T s The temperature of the admixture is an unknown quantity, which can be confirmed by measuring with a temperature sensor.

[0033] T ce The temperature of the cement is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0034] T sa The temperature of the sand is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0035] T g The temperature of the stone is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0036] T w The temperature of the water is an unknown quantity that can be measured and confirmed using a temperature sensor.

[0037] T p The temperature inside the concrete mixing shed is an unknown quantity and can be confirmed by measuring it with a temperature sensor.

[0038] T 出 The concrete discharge temperature is an unknown quantity that can be confirmed by measuring with a temperature sensor.

[0039] a1 is the first temperature coefficient of the admixture, which is a known value related to the mass;

[0040] a2 is the first temperature coefficient of cement, which is a known number related to quality;

[0041] a3 is the first temperature coefficient of the sand, a known number related to its mass;

[0042] a4 is the first temperature coefficient of the stone, which is a known number related to its mass;

[0043] a5 is the first temperature coefficient of water, a known number related to mass;

[0044] a6 is the temperature coefficient of the concrete mixing shed, which is a known value of 0.16.

[0045] b1 is the first constant.

[0046] By establishing a relationship between the concrete discharge temperature and the temperatures of cement, sand, aggregate, water, and the temperature inside the concrete mixing shed, this relationship can be used as a constraint condition for determining the minimum heating amount, ensuring that each temperature meets the requirements.

[0047] In some embodiments, a1, a2, a3, a4, a5, and b1 satisfy the following:

[0048]

[0049] in:

[0050] m s The amount of admixture can be determined by weighing.

[0051] m ce The amount of cement needed can be determined by weighing.

[0052] m sa The amount of sand used can be determined by weighing.

[0053] m g The amount of pebbles used can be determined by weighing.

[0054] m w The amount of water needed can be determined by weighing.

[0055] ω sa Let be the moisture content of the sand, a known quantity that can be measured.

[0056] ω g Let be the moisture content of the stones, which is a known quantity that can be measured.

[0057] c w The specific heat capacity of water is a fixed value, specifically 4.18 J / (g·℃).

[0058] c i This is the heat of fusion of ice, a fixed value, specifically 80 kJ / g.

[0059] It should be noted that for a given concrete structure, the concrete mix proportion is fixed, that is, the amounts of water, cement, admixtures, sand, and gravel are fixed; after the raw materials arrive on site, the moisture content of the sand and gravel is also a fixed value.

[0060] It should be noted that the second functional relationship is derived from the formula for calculating the temperature of the concrete mix exiting the mixer, T. 出 =T0-0.16(T0-T p ),

[0061] T0 = ​​[0.92(m ce T ce +m s T s +m sa T sa +m g T g +4.2T w (m w -ω sa m sa -ω g m g )+

[0062] c w (ω sa m sa T sa +ω g m g T g )-c i (ω sa m sa +ω g m g )] /

[0063] [4.2m w +0.92(m ce +m s +m sa +m g )];

[0064] Among them, T 出 The relevant formulas for T0 are those specified in the "Technical Specification for Construction of Railway Concrete Engineering". Using the T0 formula, T... 出 It is expressed as a function related to the temperature of the raw materials, which facilitates the solution of the control temperature of each raw material, so as to minimize the energy required for the insulation measures. a6 is a constant of 0.16.

[0065] In some embodiments, the actual minimum discharge temperature T of the concrete is... 出min satisfy:

[0066] T 出 ≥A;

[0067] T 出 -ΔT1-ΔT2≥B;

[0068]

[0069] in:

[0070] A represents the specified discharge temperature requirement for concrete during winter construction, specifically 10℃.

[0071] B represents the specified pouring temperature requirement for concrete during winter construction, specifically 5℃.

[0072] C represents the standard requirement value for the completion of concrete pouring during winter construction, which is 10℃ for thin-section structures and 5℃ for general structures.

[0073] ΔT1 is the temperature drop value when the concrete is transported by the tanker truck, which is related to the transportation time, the number of times the mixture is turned, the ambient temperature and the concrete discharge temperature.

[0074] ΔT2 is the temperature drop value when concrete is transported through the pump pipe, which is related to the tarpaulin material, tarpaulin thickness, transportation time, pump pipe size, ambient temperature, concrete outlet temperature, and concrete performance.

[0075] c c Let c be the specific heat capacity of concrete. For a given type of concrete, c c It is a fixed value;

[0076] m c For each cubic meter of concrete, m represents the mass of the concrete. c It is a fixed value;

[0077] c f For a given template, c is the specific heat capacity of the template. f It is a fixed value;

[0078] m f For a given cast-in-place structure, the mass of the formwork in contact with each cubic meter of concrete is m. f It is a fixed value;

[0079] c g Let c be the specific heat capacity of the reinforcing steel. For a given reinforcing steel, c g It is a fixed value;

[0080] m g For a given cast-in-place structure, the mass of reinforcing steel in contact with each cubic meter of concrete is given by m. g It is a fixed value;

[0081] T 出The concrete discharge temperature is an unknown quantity that can be confirmed by measuring with a temperature sensor.

[0082] T h The ambient temperature during construction is a known quantity that can be determined through measurement.

[0083] In some embodiments, ΔT1 and ΔT2 satisfy:

[0084] ΔT1=(αt1+0.032n)×(T 出 -T h );

[0085]

[0086] α is the temperature loss coefficient of concrete transport vehicles. For a given vehicle, α is a constant.

[0087] t1 is the transportation time of the concrete mix. For a specific construction environment, t1 is a constant.

[0088] n represents the number of times the concrete mix is ​​turned over. For a specific construction environment, n is a constant.

[0089] ω is the air permeability coefficient of the pump pipe, which is a fixed value for a specific pump pipe;

[0090] d b d represents the thickness of the external insulation layer of the pump pipe. For a specific pump pipe, d b It is a fixed value;

[0091] λ b Let λ be the thermal conductivity of the external insulation material of the pump pipe. For a specific pump pipe, λ b It is a fixed value;

[0092] t2 is the time it takes for concrete to be transported in the pump pipe. For a specific pump pipe, t2 is a fixed value.

[0093] ρ c For a specific type of concrete, ρ is the density of the concrete. c It is a fixed value;

[0094] D1 is the inner diameter of the concrete pump pipe. For a specific pump pipe, D1 is a fixed value.

[0095] T 出 The concrete discharge temperature is an unknown quantity that can be confirmed by measuring with a temperature sensor.

[0096] T h The ambient temperature during construction is a known quantity that can be determined through measurement.

[0097] ΔT1 is the temperature drop when concrete is transported by tanker truck, which is related to the transportation time, the number of times the mix is ​​turned, the ambient temperature and the concrete outlet temperature; ΔT2 is the temperature drop when concrete is transported by pump pipe, which is related to the tarpaulin material, tarpaulin thickness, transportation time, pump pipe size, ambient temperature, concrete outlet temperature and concrete properties.

[0098] In some embodiments, when solving for the minimum total energy required to heat the raw materials, the temperatures of the raw materials satisfy the following relationship:

[0099]

[0100] a1 is the first temperature coefficient of the admixture, which is a known value related to the mass;

[0101] a2 is the first temperature coefficient of cement, which is a known number related to quality;

[0102] a3 is the first temperature coefficient of the sand, a known number related to its mass;

[0103] a4 is the first temperature coefficient of the stone, which is a known number related to its mass;

[0104] a5 is the first temperature coefficient of water, a known number related to mass;

[0105] a6 is the temperature coefficient of the concrete mixing shed, which is a known value of 0.16.

[0106] b1 is the first constant;

[0107] T s The temperature of the admixture is an unknown quantity, which can be confirmed by measuring with a temperature sensor.

[0108] T ce The temperature of the cement is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0109] T sa The temperature of the sand is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0110] T g The temperature of the stone is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0111] T w The temperature of the water is an unknown quantity that can be measured and confirmed using a temperature sensor.

[0112] T p The temperature inside the concrete mixing shed is an unknown quantity and can be confirmed by measuring it with a temperature sensor.

[0113] T 出minThe minimum actual discharge temperature of the concrete is an unknown quantity that needs to be solved.

[0114] T h The ambient temperature during construction is a known quantity that can be measured.

[0115] In actual construction, the temperature of each raw material is theoretically greater than 0℃ and also greater than the ambient temperature. Furthermore, if the outlet temperature obtained from the expression for the raw material temperature is greater than or equal to the minimum outlet temperature, the temperature of each raw material can be calculated to minimize the total energy required to heat it in the first functional relationship. By controlling the temperature of each raw material, the energy required to heat it can be minimized, achieving energy conservation and environmental protection, and reducing energy waste. This ensures that the concrete outlet temperature, concrete placement temperature, and post-concrete pouring temperature meet the specifications while minimizing the heat required to heat the raw materials.

[0116] In some embodiments, the method for minimizing the total energy required to heat the raw materials includes the fmincon function method in Matlab. The fmincon function method can quickly determine the optimal control temperature for each raw material, thereby maximizing energy efficiency.

[0117] The general way to write it is:

[0118] Function to be solved:

[0119] minf(x)=(T s -T h )q s +(T ce -T h )q ce +(T sa -T h )q sa +(T g -T h )q g +(T w -T h )q w +(T p -T h )q p ;

[0120] Conditional relationship:

[0121]

[0122] Under the given conditions, the temperature of each raw material is calculated using the fmincon function in Matlab when Q reaches its minimum value. Detailed Implementation

[0123] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0124] When the average daily outdoor temperature is below 5℃ for three consecutive days or the minimum temperature is below 0℃, concrete construction should be carried out in accordance with winter construction procedures. In addition to meeting the general requirements for concrete construction, winter concrete construction should also ensure that the temperatures of raw materials, discharge temperature, placement temperature, and curing temperature meet the specifications.

[0125] In high-altitude and frigid regions, due to the long winter, concrete construction inevitably falls into the winter construction period. Traditional winter construction methods rely on experience to heat and insulate raw materials, and measure the temperature at each construction stage to ensure compliance with specifications. While this approach meets the requirements for winter concrete construction, it often involves excessive heating and insulation measures, resulting in significant energy waste.

[0126] In view of this, this application provides a method for controlling the temperature of raw materials in concrete construction during winter to solve the problem of excessive energy waste in existing methods.

[0127] Firstly, this application provides a method for controlling the temperature of raw materials used in winter concrete construction, comprising the following steps:

[0128] S100. Establish the first functional relationship between the total energy required to heat the raw materials and the temperature of each raw material.

[0129] S200. Establish a second functional relationship between the concrete discharge temperature and the temperatures of each raw material.

[0130] S300. Based on the specified values ​​of discharge temperature, pouring temperature, and pouring completion temperature, the actual minimum discharge temperature of the concrete is obtained.

[0131] S400. Based on the second functional relationship, the actual minimum discharge temperature of concrete, and the temperature requirements of raw materials, calculate the temperature of each raw material when the total energy required to heat the raw materials is minimized in the first functional relationship.

[0132] This application establishes a second functional relationship between the concrete discharge temperature and the temperatures of various raw materials. Under the premise of meeting the specified discharge temperature, formwork temperature, and final pouring temperature, the actual minimum concrete discharge temperature is obtained. Based on the second functional relationship, the actual minimum concrete discharge temperature, and the temperature requirements of the raw materials, the temperature of each raw material is calculated to minimize the total energy required to heat them in the first functional relationship. By controlling the temperature of each raw material, the energy required to heat it can be minimized, achieving energy conservation and environmental protection, and reducing energy waste. This ensures that the concrete discharge temperature, formwork temperature, and final pouring temperature meet the specifications while minimizing the heat required to heat the raw materials.

[0133] In conjunction with the first aspect, in some embodiments provided in this application, the raw materials include admixtures, cement, sand, gravel, and water. Temperature variations in these raw materials have a significant impact on energy consumption. By establishing the relationship between the aforementioned raw materials and total energy, the accuracy of energy control can be improved.

[0134] In conjunction with the first aspect, in some of the embodiments provided, the construction environment temperature is -20℃ to 5℃. Typically, a construction environment is defined as one where the average daily outdoor temperature is below 5℃ for three consecutive days or the minimum temperature is below 0℃. Energy loss is more significant in winter construction environments; therefore, within the aforementioned construction temperature range, the energy-saving effect is more pronounced.

[0135] In conjunction with the first aspect, in some embodiments provided in this application, the first functional relationship includes:

[0136] Q = (T) s -T h )q s +(T ce -T h )q ce +(T sa -T h )q sa +(T g -T h )q g +(T w -T h )q w +(T p -T h )q p ;

[0137] Where: q s The amount of heat required to raise the temperature of the enclosed space of the admixture tank by 1°C, for a given silo and a given admixture, is q. s It is a fixed value;

[0138] q ceq represents the amount of heat required to raise the temperature of the enclosed space of a cement silo by 1°C, for a given silo and a given amount of cement. ce It is a fixed value;

[0139] q sa Let q be the amount of heat required to raise the temperature of the enclosed space of a sand silo by 1°C, for a given silo and a given amount of sand. sa It is a fixed value;

[0140] q g Let q be the amount of heat required to raise the temperature of the enclosed space of a gravel silo by 1°C, for a given silo and a given amount of gravel. g It is a fixed value;

[0141] q w Let q be the amount of heat required to heat water by 1°C. w It is a fixed value;

[0142] q p q represents the amount of heat required to raise the temperature of the mixer shed by 1°C, for a given construction environment. p It is a fixed value;

[0143] T h The ambient temperature during winter construction can be determined through measurement.

[0144] T s The temperature of the admixture is an unknown quantity, which can be confirmed by measuring with a temperature sensor.

[0145] T ce The temperature of the cement is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0146] T sa The temperature of the sand is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0147] T g The temperature of the stone is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0148] T w The temperature of the water is an unknown quantity that can be measured and confirmed using a temperature sensor.

[0149] T p The temperature of the mixer shed is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0150] It should be noted that, since the temperature of the raw materials is usually not lower than the temperature of the construction environment, therefore, T s The final temperature that the admixture needs to reach; T ce The final temperature that the cement needs to reach; T sa The final temperature that the sand needs to reach; Tg The temperature that the stones ultimately need to reach; T w The final temperature that the water needs to reach; T p This refers to the final temperature that the mixing plant shed needs to reach. Generally, sand and gravel silos are fully enclosed with insulated panels, water is stored in sealed tanks, cement and admixture powder silos are fully enclosed with insulated panels, and the mixer is fully enclosed with insulated panels. Heating measures typically include using underfloor heating, heaters, oil heaters, etc., to heat the enclosed spaces of sand and gravel silos, powder silos, and mixers, and using heating rods to heat the water.

[0151] In conjunction with the first aspect, in some embodiments provided in this application, the second functional relationship includes:

[0152] T 出 =a1T s +a2T ce +a3T sa +a4T g +a5T w +a6T p +b1;

[0153] in:

[0154] T s The temperature of the admixture is an unknown quantity, which can be confirmed by measuring with a temperature sensor.

[0155] T ce The temperature of the cement is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0156] T sa The temperature of the sand is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0157] T g The temperature of the stone is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0158] T w The temperature of the water is an unknown quantity that can be measured and confirmed using a temperature sensor.

[0159] T p The temperature inside the concrete mixing shed is an unknown quantity and can be confirmed by measuring it with a temperature sensor.

[0160] T 出 The concrete discharge temperature is an unknown quantity that can be confirmed by measuring with a temperature sensor.

[0161] a1 is the first temperature coefficient of the admixture, which is a known value related to the mass;

[0162] a2 is the first temperature coefficient of cement, which is a known number related to quality;

[0163] a3 is the first temperature coefficient of the sand, a known number related to its mass;

[0164] a4 is the first temperature coefficient of the stone, which is a known number related to its mass;

[0165] a5 is the first temperature coefficient of water, a known number related to mass;

[0166] a6 is the temperature coefficient of the concrete mixing shed, which is a known value of 0.16.

[0167] b1 is the first constant.

[0168] By establishing a relationship between the concrete discharge temperature and the temperatures of cement, sand, aggregate, water, and the temperature inside the concrete mixing shed, this relationship can be used as a constraint condition for determining the minimum heating amount, ensuring that each temperature meets the requirements.

[0169] In conjunction with the first aspect, in some of the embodiments provided herein, a1, a2, a3, a4, a5, and b1 satisfy the following:

[0170]

[0171] in:

[0172] m s The amount of admixture can be determined by weighing.

[0173] m ce The amount of cement needed can be determined by weighing.

[0174] m sa The amount of sand used can be determined by weighing.

[0175] m g The amount of pebbles used can be determined by weighing.

[0176] m w The amount of water needed can be determined by weighing.

[0177] ω sa Let be the moisture content of the sand, a known quantity that can be measured.

[0178] ω g Let be the moisture content of the stones, which is a known quantity that can be measured.

[0179] c w The specific heat capacity of water is a fixed value, specifically 4.18 J / (g·℃).

[0180] c iThis is the heat of fusion of ice, a fixed value, specifically 80 kJ / g.

[0181] It should be noted that for a given concrete structure, the concrete mix proportion is fixed, that is, the amounts of water, cement, admixtures, sand, and gravel are fixed; after the raw materials arrive on site, the moisture content of the sand and gravel is also a fixed value.

[0182] It should be noted that the second functional relationship is derived from the formula for calculating the temperature of concrete mix output from the mixer: T_out = T_0 - 0.16(T_0 - T_p);

[0183] T0 = ​​[0.92(m ce T ce +m s T s +m sa T sa +m g T g +4.2T w (m w -ω sa m sa -ω g m g )+

[0184] c w (ω sa m sa T sa +ω g m g T g )-c i (ω sa m sa +ω g m g )] /

[0185] [4.2m w +0.92(m ce +m s +m sa +m g )];

[0186] Among them, T 出 The relevant formulas for T0 are those specified in the "Technical Specification for Construction of Railway Concrete Engineering". Using the T0 formula, T... 出 It is expressed as a function related to the temperature of the raw materials, which facilitates the solution of the control temperature of each raw material, so as to minimize the energy required for the insulation measures. a6 is a constant of 0.16.

[0187] In conjunction with the first aspect, in some embodiments provided in this application, the actual minimum discharge temperature T of the concrete is... 出min satisfy:

[0188] T 出 ≥A;

[0189] T 出 -ΔT1-ΔT2≥B;

[0190]

[0191] in:

[0192] A represents the specified discharge temperature requirement for concrete during winter construction, specifically 10℃.

[0193] B represents the specified pouring temperature requirement for concrete during winter construction, specifically 5℃.

[0194] C represents the standard requirement value for the completion of concrete pouring during winter construction, which is 10℃ for thin-section structures and 5℃ for general structures.

[0195] ΔT1 is the temperature drop value when the concrete is transported by the tanker truck, which is related to the transportation time, the number of times the mixture is turned, the ambient temperature and the concrete discharge temperature.

[0196] ΔT2 is the temperature drop value when concrete is transported through the pump pipe, which is related to the tarpaulin material, tarpaulin thickness, transportation time, pump pipe size, ambient temperature, concrete outlet temperature, and concrete performance.

[0197] c c Let c be the specific heat capacity of concrete. For a given type of concrete, c c It is a fixed value;

[0198] m c For each cubic meter of concrete, m represents the mass of the concrete. c It is a fixed value;

[0199] c f For a given template, c is the specific heat capacity of the template. f It is a fixed value;

[0200] m f For a given cast-in-place structure, the mass of the formwork in contact with each cubic meter of concrete is m. f It is a fixed value;

[0201] c g Let c be the specific heat capacity of the reinforcing steel. For a given reinforcing steel, c g It is a fixed value;

[0202] m g For a given cast-in-place structure, the mass of reinforcing steel in contact with each cubic meter of concrete is given by m. g It is a fixed value;

[0203] T 出 The concrete discharge temperature is an unknown quantity that can be confirmed by measuring with a temperature sensor.

[0204] T h The ambient temperature during construction is a known quantity that can be determined through measurement.

[0205] In conjunction with the first aspect, in some embodiments provided herein, ΔT1 and ΔT2 satisfy:

[0206] ΔT1=(αt1+0.032n)×(T 出 -T h );

[0207]

[0208] α is the temperature loss coefficient of concrete transport vehicles. For a given vehicle, α is a constant.

[0209] t1 is the transportation time of the concrete mix. For a specific construction environment, t1 is a constant.

[0210] n represents the number of times the concrete mix is ​​turned over. For a specific construction environment, n is a constant.

[0211] ω is the air permeability coefficient of the pump pipe, which is a fixed value for a specific pump pipe;

[0212] d b d represents the thickness of the external insulation layer of the pump pipe. For a specific pump pipe, d b It is a fixed value;

[0213] λ b Let λ be the thermal conductivity of the external insulation material of the pump pipe. For a specific pump pipe, λ b It is a fixed value;

[0214] t2 is the time it takes for concrete to be transported in the pump pipe. For a specific pump pipe, t2 is a fixed value.

[0215] ρ c For a specific type of concrete, ρ is the density of the concrete. c It is a fixed value;

[0216] D1 is the inner diameter of the concrete pump pipe. For a specific pump pipe, D1 is a fixed value.

[0217] T 出 The concrete discharge temperature is an unknown quantity that can be confirmed by measuring with a temperature sensor.

[0218] T h The ambient temperature during construction is a known quantity that can be determined through measurement.

[0219] ΔT1 is the temperature drop when concrete is transported by tanker truck, which is related to the transportation time, the number of times the mix is ​​turned, the ambient temperature and the concrete outlet temperature; ΔT2 is the temperature drop when concrete is transported by pump pipe, which is related to the tarpaulin material, tarpaulin thickness, transportation time, pump pipe size, ambient temperature, concrete outlet temperature and concrete properties.

[0220] In conjunction with the first aspect, in some embodiments provided in this application, when solving for the minimum total energy required to heat the raw materials, the temperatures of each raw material satisfy the following relationship:

[0221]

[0222] The function to be solved is:

[0223] Q = (T) s -T h )q s +(T ce -T h )q ce +(T sa -T h )q sa +(T g -T h )q g +(T w -T h )q w +(T p -T h )q p ;

[0224] a1 is the first temperature coefficient of the admixture, which is a known value related to the mass;

[0225] a2 is the first temperature coefficient of cement, which is a known number related to quality;

[0226] a3 is the first temperature coefficient of the sand, a known number related to its mass;

[0227] a4 is the first temperature coefficient of the stone, which is a known number related to its mass;

[0228] a5 is the first temperature coefficient of water, a known number related to mass;

[0229] a6 is the temperature coefficient of the concrete mixing shed, which is a known value of 0.16.

[0230] b1 is the first constant;

[0231] T s The temperature of the admixture is an unknown quantity, which can be confirmed by measuring with a temperature sensor.

[0232] T ce The temperature of the cement is an unknown quantity, which can be confirmed by measuring it with a temperature sensor.

[0233] T sa The temperature of the sand is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0234] T g The temperature of the stone is an unknown quantity that can be confirmed by measuring it with a temperature sensor.

[0235] T w The temperature of the water is an unknown quantity that can be measured and confirmed using a temperature sensor.

[0236] T p The temperature inside the concrete mixing shed is an unknown quantity and can be confirmed by measuring it with a temperature sensor.

[0237] T 出min The minimum actual discharge temperature of the concrete is an unknown quantity that needs to be solved.

[0238] T h The ambient temperature during construction is a known quantity that can be measured.

[0239] In actual construction, the temperature of each raw material is theoretically greater than 0℃ and also greater than the ambient temperature. Furthermore, if the outlet temperature obtained from the expression for the raw material temperature is greater than or equal to the minimum outlet temperature, the temperature of each raw material can be calculated to minimize the total energy required to heat it in the first functional relationship. By controlling the temperature of each raw material, the energy required to heat it can be minimized, achieving energy conservation and environmental protection, and reducing energy waste. This ensures that the concrete outlet temperature, concrete placement temperature, and post-concrete pouring temperature meet the specifications while minimizing the heat required to heat the raw materials.

[0240] In conjunction with the first aspect, in some embodiments provided in this application, the method for minimizing the total energy required to heat the raw materials includes the fmincon function method in Matlab. The fmincon function method can quickly determine the optimal control temperature for each raw material, thereby maximizing energy efficiency.

[0241] In summary, by establishing a second functional relationship between the concrete discharge temperature and the temperatures of each raw material, and under the premise of meeting the specified values ​​for discharge temperature, placement temperature (i.e., completion temperature), the actual minimum concrete discharge temperature is obtained. Based on the second functional relationship, the actual minimum concrete discharge temperature, and the temperature requirements of the raw materials, the temperature of each raw material is calculated to minimize the total energy required to heat it in the first functional relationship. By controlling the temperature of each raw material, the energy required to heat it can be minimized, achieving energy conservation and environmental protection, and reducing energy waste. This approach ensures that the concrete discharge temperature, placement temperature, and completion temperature meet the specifications while minimizing the heat required to heat the raw materials.

[0242] The terms "comprising" and "having," and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0243] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0244] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0245] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0246] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for controlling the temperature of raw materials during winter concrete construction, characterized in that, Includes the following steps: Establish the first functional relationship between the total energy required to heat the raw materials and the temperature of each raw material; Establish a second functional relationship between the concrete discharge temperature and the temperatures of each raw material; Based on the specified values ​​for discharge temperature, pouring temperature, and pouring completion temperature, the actual minimum discharge temperature of the concrete is obtained. Based on the second functional relationship, the actual minimum discharge temperature of concrete, and the temperature requirements of raw materials, the temperature of each raw material is calculated when the total energy required to heat the raw materials in the first functional relationship is minimized. The first functional relationship includes: Where: q s The amount of heat required to raise the temperature of the enclosed space of the mixing tank by 1°C; q ce The amount of heat required to raise the temperature of the enclosed space of a cement silo by 1°C. q sa The amount of heat required to raise the temperature of the enclosed space of the sand silo by 1°C. q g The amount of heat required to raise the temperature of the enclosed space of the gravel silo by 1°C. q w The amount of heat required to heat water by 1°C. q p This refers to the amount of heat required for the mixer shed to heat up by 1°C. T h The ambient temperature for construction during winter; T s Temperature of the admixture; T ce The temperature of the cement; T sa The temperature of the sand; T g The temperature of the stones; T w The temperature of the water; T p The temperature of the mixer shed; The second functional relationship includes: T 出 =a1T s +a2T ce +a3T sa +a4T g +a5T w +a6T p +b1; in: T s Temperature of the admixture; T ce The temperature of the cement; T sa The temperature of the sand; T g Temperature of the stones; T w The temperature of the water; T p The temperature inside the concrete mixing shed; T 出 The concrete discharge temperature; a1 is the first temperature coefficient of the admixture; a2 is the first temperature coefficient of cement; a3 is the first temperature coefficient of the sand; a4 is the first temperature coefficient of the stone; a5 is the first temperature coefficient of water; a6 is the temperature coefficient of the temperature inside the concrete mixing shed. b1 is the first constant; a1, a2, a3, a4, a5, and b1 satisfy: in: m s This refers to the amount of admixture used; m ce This refers to the amount of cement used. m sa The amount of sand used; m g The amount of pebbles used; m w The amount of water used; ω sa The moisture content of the sand; ω g The moisture content of the stones; c w This is the specific heat capacity of water; c i It is the heat of fusion of ice; The actual minimum discharge temperature T of the concrete 出min satisfy: T 出 ≥A; T 出 -ΔT1-ΔT2≥B; in: A represents the standard requirement for the discharge temperature of concrete during winter construction. B represents the specified pouring temperature requirement for concrete during winter construction. C represents the standard requirement value when the concrete pouring is completed during winter construction. ΔT1 is the temperature drop value when the concrete is transported by the tanker truck; ΔT2 is the temperature drop value when the pump pipe transports concrete; c c This refers to the specific heat capacity of concrete. m c The mass of concrete per cubic meter; c f The specific heat capacity of the template; m f The mass of the formwork in contact with each cubic meter of concrete; c g This refers to the specific heat capacity of the reinforcing steel. m g The mass of reinforcing steel bars in contact with each cubic meter of concrete; T 出 The concrete discharge temperature; T h The ambient temperature during construction; ΔT1 and ΔT2 satisfy: ； α is the temperature loss coefficient of concrete transport vehicles; t1 is the transportation time of the concrete mix; n represents the number of times the concrete mix has been processed; ω is the air permeability coefficient of the pump pipe; d b This refers to the thickness of the external insulation layer of the pump pipe; λ b The thermal conductivity of the external insulation material of the pump pipe; t2 is the time it takes for concrete to be transported in the pump pipe; ρ c The density of concrete; D1 is the inner diameter of the concrete pump pipe; T 出 The concrete discharge temperature; T h The ambient temperature during construction; When determining the minimum total energy required to heat the raw materials, the temperatures of each raw material satisfy the following relationship: a1 is the first temperature coefficient of the admixture; a2 is the first temperature coefficient of cement; a3 is the first temperature coefficient of the sand; a4 is the first temperature coefficient of the stone; a5 is the first temperature coefficient of water; a6 is the temperature coefficient of the temperature inside the concrete mixing shed. b1 is the first constant; T s Temperature of the admixture; T ce The temperature of the cement; T sa The temperature of the sand; T g The temperature of the stones; T w The temperature of the water; T p The temperature inside the concrete mixing shed; T 出min This represents the minimum actual discharge temperature of the concrete from the mixer. T h The ambient temperature during construction.

2. The method for controlling the temperature of raw materials in winter concrete construction as described in claim 1, characterized in that, The raw materials include admixtures, cement, sand, gravel, and water.

3. The method for controlling the temperature of raw materials in winter concrete construction as described in claim 1, characterized in that: The ambient temperature during construction is -20℃ to 5℃.

4. The method for controlling the temperature of raw materials in winter concrete construction as described in claim 1, characterized in that, One method for finding the minimum total energy required to heat the raw materials is the fmincon function in Matlab.

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