A design method for mix ratio of prestressed concrete with machine-made sand and gravel aggregate based on deformation control

Abstract

The present invention relates to a method for designing the mix ratio of prestressed concrete with machine-made sand and gravel aggregates based on deformation control, comprising the following steps: 1) according to the characteristics of prestressed concrete with machine-made sand and gravel aggregates, low creep is determined as the main design goal; 2) based on the relationship model between concrete creep and elastic modulus, the relationship between concrete creep and aggregates, interfaces and paste is established; 3) the material selection principle and optimization technology for raw materials used for low-creep prestressed concrete with machine-made sand and gravel aggregates are clarified. The present invention innovates the method for designing the mix ratio of prestressed concrete with machine-made sand and gravel aggregates based on deformation control. The prepared prestressed concrete with machine-made sand and gravel aggregates has the characteristics of extremely low creep and good deformation matching of different components, and can better serve major projects such as high-speed railways, and greatly reduce the upward deformation capacity of prestressed concrete structures.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a method for designing the mix ratio of machine-made sand and gravel aggregate prestressed concrete based on deformation control. Background Art

[0002] With the steady advancement of the engineering development strategy in the construction field of my country, major projects such as railways and highways have developed rapidly. However, due to the policy of limiting the extraction of river sand resources and seasonal effects, there is a serious shortage of river sand raw materials for concrete that meet the requirements, especially in mountainous projects mainly in Yunnan, Guizhou and Sichuan. This not only causes the quality of raw materials to be unstable and the price to rise, but also affects the construction period of the project. In serious cases, it leads to insufficient durability and quality decline of the project, affecting the service performance and service life of the project. The application of machine-made sand and gravel aggregate is the main measure to solve the difficulties in using sand for concrete, and it is also an important direction for the development of green building materials. The current standards for prestressed structures of railway projects, such as "Precast Post-Tensioned Prestressed Concrete Simply Supported Beams for High-Speed ​​Railway" (TB / T 3423-2016), "Pre-Tensioned Prestressed Concrete Track Slabs for High-Speed ​​Railway CRTSⅢ Type Ballastless Track" (Q / CR 567-2017), and "Concrete Sleepers" (TB / T 2190-2013), propose that the fine aggregate in concrete for prestressed structures such as beams, track slabs, and sleepers should be natural, clean, and hard river sand.

[0003] In view of the limitation of standards and the current situation that there is little research on the application of machine-made sand in prestressed structures of railway engineering, Zhong Meiqin of the China Railway Science Institute studied the possibility of using machine-made sand concrete to prepare railway prestressed components. Although the research results show that it is feasible to use machine-made sand in railway concrete prestressed components, there is no research on the shrinkage and creep of machine-made sand and gravel aggregate prestressed concrete for railways. In recent years, Li Huajian and others of the China Railway Science Institute have systematically studied the performance of machine-made sand and gravel aggregate prestressed concrete for railways, and prefabricated machine-made sand concrete T-beams, track slabs, and sleepers that meet the standard requirements, but did not propose a mix design method for machine-made sand and gravel aggregate prestressed concrete based on deformation control. Chinese patent CN 109369097A "A low-shrinkage, low-creep, crack-resistant, high-performance large-volume concrete" discloses a low-shrinkage, low-creep, crack-resistant, high-performance large-volume concrete. The significant features of the present invention are that the concrete mix ratio does not require a special mixing process for mixing concrete, the mixing is simple, the mixing and feeding order can be changed, and the prepared concrete has the characteristics of low creep, and the 365d shrinkage rate is ≤519×10 -6 、365d compressive creep ≤28.0×10 -6 / MPa, 365d compressive creep coefficient ≤0.72, but the present invention is mainly aimed at cast-in-place large-volume concrete structures, and there is no report on the creep of prestressed concrete structures; Chinese patent CN 102701654 B "A type of low creep concrete" discloses the formula of low creep concrete. The biggest advantage of the formula is that it can be prepared by matching inert admixtures with different elastic moduli according to different requirements of low creep values. However, these patents lack theoretical support and guidance, and lack research on low creep of machine-made sand concrete or prestressed concrete. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to invent a method for designing the mix ratio of machine-made sand and gravel aggregate prestressed concrete based on deformation control.

[0005] The purpose of the present invention can be achieved by the following technical scheme: a method for designing the mix ratio of machine-made sand and gravel aggregate prestressed concrete based on deformation control, characterized in that the method comprises the following steps: 1) according to the characteristics of machine-made sand and gravel aggregate prestressed concrete, low creep is determined as its main design goal; 2) based on the relationship model between concrete creep and elastic modulus, the relationship between concrete creep and aggregate, interface and paste is established; 3) the material selection principle and optimization technology for raw materials used for low creep machine-made sand and gravel aggregate prestressed concrete are clarified.

[0006] In the step 1), the prestressed concrete with manufactured sand and gravel aggregates starts to hold the load for 7 days, and the creep index of holding the load for 360 days mainly includes three levels: Level I is the creep less than 10×10 -6 , the creep degree is between 10×10 -6 ~25×10 -6 , The creep degree is greater than 25×10 -6 .

[0007] Preferably, the low creep design target level is level I.

[0008] The relationship between the creep of concrete and aggregate, interface and paste in the step 2) is mainly established based on the combination of a prediction model of concrete creep and elastic modulus, a prediction model of concrete elastic modulus based on sandstone aggregate and paste, and a prediction model of paste elastic modulus based on paste compressive strength.

[0009] Preferably, the calculation formula based on the concrete creep and elastic modulus prediction model in step 2) is:

[0010] ε ct =g 1 ·g 2 ·g 3 ·g 4 ·g5 ·σ c / E 28 (1)

[0011] Where ε ct is the compressive creep of concrete, σ c is the compressive stress of concrete, E 28 is the elastic modulus of concrete at 28d, g 1 , g 2 , g 3 , g 4 , g 5 They represent the relative humidity of the environment, the curing age of concrete before loading, the composition of the concrete mixture (cement content and water-binder ratio), the shape and size of the structure, and the load-holding time.

[0012] Preferably, in the step 2), it is assumed that the strains of various parts of the concrete are the same, and as a preliminary approximation, the lateral deformation is ignored, and the calculation formula of the concrete elastic modulus prediction model based on the elastic modulus of aggregate and paste is:

[0013] E 28 =E m V m +E g V g (2)

[0014] Where E m 、E g are the elastic modulus of paste and aggregate, V m 、V g are the volume fractions of paste and aggregate, respectively, and V m +V g =1.

[0015] Preferably, the calculation formula of the slurry elastic modulus prediction model based on the slurry compressive strength in step 3) is:

[0016] E m =4.0279σ s 0.1794 (3)

[0017] Where σ s is the compressive strength of the slurry.

[0018] Combining equations (1) to (3), we can get:

[0019] ε ct =g 1 ·g 2 ·g 3 ·g 4 ·g 5 ·σ c / (4.0279σ s0.1794 V m +E g V g ) (4)

[0020] Equation (4) establishes the relationship between concrete creep and aggregate, interface and paste.

[0021] The material selection principles and optimization techniques for the low creep concrete in step 3) are mainly aimed at aggregates, interfaces and pastes.

[0022] Preferably, the principle of aggregate selection in step 3) is to select coarse aggregate with high elastic modulus, large particle size, good particle shape and gradation, and select aggregate with good particle shape, gradation, low MB value and low stone powder content. The aggregate optimization technology is to increase the volume fraction of aggregate in concrete.

[0023] Further preferably, the high elastic modulus is 100 GPa~130 GPa, the uniaxial compressive strength is not less than 100 MPa, and the parent rock is mainly one of diorite, granite, basalt, limestone, tuff and quartzite.

[0024] Further preferably, the machine-made sand and gravel aggregate is continuously graded from 0 mm to 31.5 mm, and its fineness modulus is from 4.6 to 6.0.

[0025] Further preferably, the coarse aggregate particle shape is preferably such that the roundness of the coarse aggregate is greater than 0.75, and the needle-like content is less than 5% of the total mass of the coarse aggregate.

[0026] Further preferably, the machine-made sand has a roundness greater than 0.80, an aspect ratio less than 1.6, a grading of medium sand in zone II, an MB value of the machine-made sand less than 1.4, and a stone powder content less than 5%.

[0027] Further preferably, the volume fraction of the aggregate in the concrete is between 70% and 80%.

[0028] Preferably, the interface optimization technology in step 3) is to reduce the thickness of the interface transition zone and reduce the porosity of the interface transition zone.

[0029] Further preferably, the reduction of the thickness and porosity of the interface transition zone is mainly achieved by using a low water-to-binder ratio and incorporating one or more of the silicon-based materials.

[0030] More preferably, the low water-cement ratio is less than 0.32, and a polycarboxylic acid high-efficiency water reducer is added.

[0031] More preferably, the silicon-based material is one or more of fly ash, silica ash, rice husk ash, slag powder, and metakaolin.

[0032] Preferably, the material selection principle and optimization technology of the slurry in step 3) are to add mineral admixtures that significantly increase the elastic modulus of the slurry and reduce the gas content of the slurry.

[0033] Further preferably, the mineral admixture that significantly improves the elastic modulus of the slurry is an ultrafine mineral admixture that can increase the calcium-silicon ratio in the cement slurry.

[0034] More preferably, the mineral admixture added to increase the calcium-silicon ratio in the cement paste is calcium carbonate powder.

[0035] More preferably, the ultrafine mineral admixture is mainly one or more of nano silicon dioxide and ground stone powder.

[0036] Further preferably, the reducing the gas content of the slurry is to control the gas content of the slurry to be between 2% and 4%.

[0037] More preferably, the slurry gas content can be controlled to be between 2% and 4% by using a defoaming agent or a small amount of an air entraining agent or more.

[0038] The deformation-controlled prestressed concrete with machine-made sand and gravel aggregate is composed of machine-made sand and gravel aggregate of the same lithology and stone powder admixtures supplemented with cementitious materials, water, admixtures, etc., and is prepared by the following components in parts by weight:

[0039] Cement with strength grade > 42.5 100,

[0040] Specific surface area not less than 600m 2 / kg finely ground stone powder 7-15,

[0041] Mineral admixture 10-55,

[0042] 0mm~31.5mm continuous graded mixed machine-made sand and gravel aggregate 330-416,

[0043] Polycarboxylic acid high efficiency water reducing agent 0.8-1.5,

[0044] Water: 32.76-54.4.

[0045] The preparation method comprises the following steps: adding cementitious material and machine-made sand and gravel aggregate into a vibrating stirring device in proportion, forcibly stirring for 60 seconds, adding 3 / 4 water and an admixture into the obtained mixture, forcibly stirring for 60 seconds, and then adding 1 / 4 water and an admixture into the obtained mixture, forcibly stirring for 60 seconds to 180 seconds to obtain a concrete mixture, and then turning on the vibrating device for 60 seconds to 120 seconds to make the cement, machine-made sand and gravel aggregate and water mixed more evenly.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] (1) Quantitative design of low creep of manufactured sand and gravel aggregate. Previous inventions have little research on the creep of prestressed concrete with manufactured sand and gravel aggregate, and the creep degree of concrete prepared by the disclosed invention patents is still relatively high, which cannot meet the design goal of low creep grade prestressed concrete with manufactured sand and gravel aggregate. The present invention is based on theoretical design, material selection and optimization, etc., to quantitatively design low creep prestressed concrete with manufactured sand and gravel aggregate.

[0048] (2) The material selection principle is appropriate and reliable. On the basis of giving priority to the design of low creep machine-made sand and gravel aggregate prestressed concrete, the creep difference between different components of concrete is also considered. This is something that other invention patents have not considered and is also a very important characteristic affecting concrete creep. The present invention reduces the differences in elastic modulus and thermodynamic properties of different components by optimizing raw materials.

[0049] (3) Advanced mix design method. The mix design concept of the present invention is composed of the same rock type machine-made sand and gravel aggregate and stone powder admixture supplemented with cementitious materials, water, admixtures, etc. From the perspectives of powder modification, key index requirements of machine-made sand, key index control of coarse aggregate, and optimization of mineral admixtures, based on relevant theoretical support, the mix design of machine-made sand and gravel aggregate prestressed concrete is proposed through different components and different scales. The method is extremely advanced.

[0050] The principle of a design method for mix ratio of machine-made sand and gravel aggregate prestressed concrete based on deformation control is as follows:

[0051] The purpose of a design method for mix proportion of prestressed concrete with manufactured sand and gravel aggregate based on deformation control is to improve the overall elastic modulus of concrete and reduce the difference in elastic modulus of different components. Therefore, a prediction model of creep of prestressed concrete with manufactured sand and gravel aggregate related to aggregate, interface and paste is established as follows:

[0052] ε ct =g 1 ·g 2 ·g 3 ·g 4 ·g 5 ·σ c / (4.0279σ s 0.1794 V m +E g V g )

[0053] Where ε ct is the compressive creep of concrete structure, σ c is the compressive stress, E 28 is the elastic modulus of concrete at 28d, g 1 , g 2 , g3 , g 4 , g 5 They represent the relative humidity of the environment, the curing age of concrete before loading, the composition of the concrete mixture (cement content and water-cement ratio), the shape and size of the structure, and the load holding time. m 、E g are the elastic modulus of paste and aggregate, V m 、V g are the volume fractions of paste and aggregate, respectively, and V m +V g =1,σ s is the compressive strength of the slurry.

[0054] Based on the optimization theoretical prediction model of low creep, the elastic modulus of concrete is divided into three parts: aggregate, interface and paste, which can better establish the relationship between concrete creep and concrete raw materials.

[0055] As for aggregates, in concrete, aggregates occupy a large volume fraction and play the role of skeleton. Moreover, the elastic modulus of aggregates is very high, so the elastic modulus of aggregates has the most significant effect on the elastic modulus of concrete. g The larger the volume fraction V g When the value is larger, the elastic modulus of concrete is larger and its creep is lower; the larger the maximum particle size of coarse aggregate and the better the gradation, the larger its volume fraction can be, thus improving the elastic modulus of concrete; in addition, the better particle shape of coarse aggregate and fine aggregate can make the influencing factor g in the prediction model 4 Smaller, thereby reducing the creep of concrete.

[0056] For the interface, it is a key factor affecting the reduction of the elastic modulus of concrete. The elastic modulus of the interface can be improved by reducing the thickness and porosity of the interface transition zone. Specifically, measures such as using a lower water-binder ratio or adding silicon-based mineral admixtures can be used to improve it. The main mechanism is to reduce the moisture, porosity and calcium hydroxide content in the transition zone.

[0057] For the slurry, it is mainly composed of CSH gel and pores, so the improvement of its elastic modulus is mainly achieved by increasing the calcium-silicon ratio in the cement slurry to increase the elastic modulus of the CSH gel. The addition of ultrafine stone powder and mineral admixtures can play the role of crystal nuclei to promote hydration and fill the pores of cement stone, thereby promoting the improvement of the slurry elastic modulus.

[0058] Through the above-mentioned raw material selection principles and optimization technology, low creep machine-made sand and gravel aggregate prestressed concrete can be formulated. At the same time, based on the characteristics that the elastic modulus of coarse aggregate is relatively high, while the elastic modulus of slurry and interface is relatively low, the present invention reduces the difference in elastic modulus between different components in mix design by increasing the elastic modulus of interface and slurry, and minimizes the difference in elastic modulus between different components as much as possible by using stone, sand and powder of the same lithology. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0060] Figure 1 The present invention is a flow chart of a method for designing the mix ratio of machine-made sand and gravel aggregate prestressed concrete based on deformation control. DETAILED DESCRIPTION

[0061] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. These embodiments are only intended to illustrate the present invention but not to limit the scope of the present invention.

[0062] Example 1

[0063] The creep design target of prestressed concrete with manufactured sand and gravel aggregate under compression for 360 days is less than 10×10 -6 / MPa, the concrete size is 100mm×100mm×300mm, the average temperature of the curing environment is 20℃, the relative humidity is 95%, the concrete is removed after curing for 7 days, and the load is σ c =200KN.

[0064] Among the raw materials, cement is P.O42.5 grade and the cement dosage is 400kg / m 3 The water-cement ratio is 0.32, the coarse aggregate is basalt, the machine-made sand and gravel aggregate is 0mm~31.5mm continuous grading, its fineness modulus is 5.2, the roundness of the coarse aggregate is 0.75, the needle-like content is 4%, the fine aggregate is basalt machine-made sand, the grading is II zone medium sand, the MB value is 1.2, the stone powder content is 4%, the roundness of the machine-made sand is 0.81, the aspect ratio is 1.58, the volume fraction of the aggregate is 74%, the fly ash is Class I fly ash, and the dosage is 60kg / m 3 , the amount of rice husk ash is 60kg / m 3 The specific surface area of ​​ground basalt powder is 800m 2 / kg, dosage is 20kg / m 3, the air content is 3%. Add cementitious materials and machine-made sand and gravel aggregates to the vibrating stirring device in proportion, force stirring for 60 seconds, add 3 / 4 water and admixtures to the resulting mixture, force stirring for 60 seconds, then add 1 / 4 water and admixtures to the resulting mixture, force stirring for 60 seconds to 180 seconds to obtain a concrete mixture, and then turn on the vibration device for 60 seconds to 120 seconds to make the cement, machine-made sand and gravel aggregates and water mix more evenly.

[0065] Example 2

[0066] The creep design target of prestressed concrete with manufactured sand and gravel aggregate under compression for 360 days is less than 10×10 -6 / MPa, the concrete size is 100mm×100mm×300mm, the average temperature of the curing environment is 20℃, the relative humidity is 95%, the concrete is removed after curing for 7 days, and the load is σ c =200KN.

[0067] Among the raw materials, cement is P.O42.5 grade and the cement dosage is 380kg / m 3 The water-cement ratio is 0.30, the coarse aggregate is diorite, the machine-made sand and gravel aggregate is 0mm~31.5mm continuous gradation, its fineness modulus is 5.4, the roundness of the coarse aggregate is 0.8, the needle-like content is 4%, the fine aggregate is diorite machine-made sand, the grading is II zone medium sand, the MB value is 1.0, the stone powder content is 3%, the roundness of the machine-made sand is 0.83, the aspect ratio is 1.5, the volume fraction of the aggregate is 80%, the fly ash is Class I fly ash, and the dosage is 60kg / m 3 , the amount of rice husk ash is 60kg / m 3 The specific surface area of ​​the ground diorite powder is 1000m 2 / kg, dosage is 30kg / m 3 , the dosage of nano silicon dioxide is 10kg / m 3 , the air content is 2%. Add cementitious materials and machine-made sand and gravel aggregates to the vibrating stirring device in proportion, force stirring for 60 seconds, add 3 / 4 water and admixtures to the resulting mixture, force stirring for 60 seconds, then add 1 / 4 water and admixtures to the resulting mixture, force stirring for 60 seconds to 180 seconds to obtain a concrete mixture, and then turn on the vibration device for 60 seconds to 120 seconds to make the cement, machine-made sand and gravel aggregates and water mix more evenly.

[0068] Example 3

[0069] The creep design target of prestressed concrete with manufactured sand and gravel aggregate under compression for 360 days is less than 10×10 -6 / MPa, the concrete size is 100mm×100mm×300mm, the average temperature of the curing environment is 20℃, the relative humidity is 95%, the concrete is removed after curing for 7 days, and the load is σ c =200KN.

[0070] Among the raw materials, cement is P.O42.5 grade and the cement dosage is 350kg / m 3 The water-cement ratio is 0.28, the coarse aggregate is fine-grained granite, the machine-made sand and gravel aggregate is continuously graded from 0mm to 31.5mm, its fineness modulus is 5.5, the roundness of the coarse aggregate is 0.85, the needle-like content is 4%, the fine aggregate is diorite machine-made sand, the grading is II zone medium sand, the MB value is 0.8, the stone powder content is 3%, the roundness of the machine-made sand is 0.85, the aspect ratio is 1.4, the volume fraction of the aggregate is 77%, and the amount of rice husk ash is 70kg / m 3 The dosage of kaolin is 70kg / m 3 The specific surface area of ​​fine-grained granite powder is 1500m 2 / kg, dosage is 30kg / m 3 , the dosage of nano silicon dioxide is 30kg / m 3 , the air content is 2.5%. Add cementitious materials and machine-made sand and gravel aggregates to the vibrating stirring device in proportion, force stirring for 60 seconds, add 3 / 4 water and admixtures to the resulting mixture, force stirring for 60 seconds, then add 1 / 4 water and admixtures to the resulting mixture, force stirring for 60 seconds to 180 seconds to obtain a concrete mixture, and then turn on the vibration device for 60 seconds to 120 seconds to make the cement, machine-made sand and gravel aggregates and water mix more evenly.

[0071] The measured properties of the low creep machine-made sand and gravel aggregate prestressed concrete mix designs provided in Examples 1 to 3 and the comparative machine-made sand and gravel aggregate prestressed concrete mix designs are shown in Table 1.

[0072] Table 1 Performance test of prestressed concrete with different proportions of machine-made sand and gravel aggregate

[0073]

[0074] It can be seen from Table 1 that compared with the prestressed concrete with machine-made sand and gravel aggregates designed with the comparative mix ratio, the creep of the concrete of Examples 1 to 3 is significantly lower, basically achieving the goal of low creep design. In addition, it can be seen that the difference in elastic modulus of different components of the concrete of Examples 1 to 3 is relatively small, and it can be seen that the creep between different components of these groups of concrete is relatively uniform. Further analysis shows that from Examples 1 to 3, it can be seen that Examples 2 and 3 meet the design goal of low creep of the present invention. At the same time, it can be found that although the creep of Example 3 is slightly greater than that of Example 2, the elastic modulus between its different components is closer, which meets the design goal of the present invention and is conducive to the long-term and safe use of prestressed concrete with machine-made sand and gravel aggregates.

Claims

1. A method for designing mix proportion of prestressed concrete with machine-made sand and gravel aggregate based on deformation control, characterized in that: The following steps are involved: 1) According to the characteristics of prestressed concrete with manufactured sand and gravel aggregate, low creep is determined as its design goal; 2) Based on the relationship model between concrete creep and elastic modulus, the relationship between concrete creep and aggregate, interface and paste was established; 3) The selection principle and optimization technology of raw materials for low creep machine-made sand and gravel aggregate prestressed concrete were clarified; The relationship between the creep of concrete and aggregate, interface and paste in step 2) is established by combining a prediction model based on concrete creep and elastic modulus, a prediction model based on sandstone aggregate and paste elastic modulus, and a prediction model based on paste elastic modulus of paste compressive strength; The calculation formula based on the concrete creep and elastic modulus prediction model in step 2) is: e ct =g1·g2·g3·g4·g5·s c / E 28 (1) Where ε ct is the compressive creep of concrete structure, σ c is the compressive stress, E 28 is the elastic modulus of concrete at 28 days, g1, g2, g3, g4, g5 represent the relative humidity of the environment, the curing age of concrete before loading, the composition of the concrete mixture, the thickness of the structure, and the load holding time, respectively; the concrete mixture composition is the amount of cement and the water-binder ratio; The calculation formula of the concrete elastic modulus prediction model based on the elastic modulus of aggregate and paste is: E 28 =E m V m +E g V g (2) Where E m 、E g are the elastic modulus of paste and aggregate, V m 、V g are the volume fractions of paste and aggregate, respectively, and V m +V g =1; The calculation formula of the slurry elastic modulus prediction model based on the slurry compressive strength is: E m =4.0279σ s 0.1794 (3) Where σ s is the compressive strength of the slurry; Combining equations (1) to (3), we can get: ε ct =g1·g2·g3·g4·g5·σ c / (4.0279σ s 0.1794 V m +E g V g ) (4) Equation (4) establishes the relationship between concrete creep and aggregate, interface and paste; The material selection principles and optimization techniques for the raw materials used in step 3) of low to medium creep concrete are aimed at aggregates, interfaces and pastes in concrete; The specific indicators of the material selection principle of the machine-made sand and gravel aggregate in the step 3) are as follows: the elastic modulus of the parent rock of the machine-made sand and gravel aggregate is 100GPa~130GPa, the uniaxial compressive strength is not less than 100MPa, the parent rock is one of diorite, granite, basalt, limestone, tuff and quartzite, the machine-made sand and gravel aggregate is 0mm~31.5mm continuous gradation, and its fineness modulus is 4.6~6.0; the roundness of the coarse aggregate is greater than 0.75, and the needle-like content is less than 5% of the total mass of the coarse aggregate; the roundness of the machine-made sand is greater than 0.80, the aspect ratio is less than 1.6, the machine-made sand grading is medium sand in zone II, the MB value of the machine-made sand is less than 1.4, and the stone powder content is less than 5%; the volume fraction of the machine-made sand and gravel aggregate in the concrete is between 70% and 80%; The interface optimization technology in step 3) is to reduce the thickness and porosity of the interface transition zone. The specific optimization technology is as follows: by using a low water-binder ratio of less than 0.32, adding a polycarboxylic acid high-efficiency water reducer, and adding one or more of fly ash, silica fume, rice husk ash, slag powder, and metakaolin materials; The material selection principle and optimization technology of the slurry in step 3) are to add mineral admixtures that significantly improve the elastic modulus of the slurry and reduce the gas content of the slurry. The specific material selection principles and optimization technologies are as follows: one or more of calcium carbonate powder, nano-silicon dioxide, and ground stone powder are added, and the gas content of the slurry is between 2% and 4%.

2. The method for designing mix ratio of prestressed concrete with machine-made sand and gravel aggregate based on deformation control according to claim 1 is characterized in that: In the step 1), the prestressed concrete with manufactured sand and gravel aggregates starts to hold the load for 7 days, and the creep index of holding the load for 360 days includes three levels: Level I is the creep less than 10×10 -6 , Grade II is creep between 10×10 -6 ~25×10 -6 , Grade III means creep degree is greater than 25×10 -6 .

3. The method for designing mix ratio of prestressed concrete with machine-made sand and gravel aggregate based on deformation control according to claim 1 is characterized in that: The deformation-controlled prestressed concrete with machine-made sand and gravel aggregate is composed of machine-made sand and gravel aggregate of the same lithology and stone powder admixtures supplemented with cementitious materials, water, and admixtures, and is prepared from the following components in parts by weight: Cement 100 with strength grade not less than 42.5, Specific surface area not less than 600m 2 / kg finely ground stone powder 7-15, Mineral admixture 10-55, 0mm~31.5mm continuous graded mixed machine-made sand and gravel aggregate 330-416, Polycarboxylic acid high efficiency water reducing agent 0.8-1.5, Water: 32.76-54.4.

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