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DL/T 5786-2019: (Hydraulic plastic concrete mix design procedure)
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(Hydraulic plastic concrete mix design procedure)
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DL/T 5786-2019
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Basic data | Standard ID | DL/T 5786-2019 (DL/T5786-2019) | | Description (Translated English) | (Hydraulic plastic concrete mix design procedure) | | Sector / Industry | Electricity & Power Industry Standard (Recommended) | | Classification of Chinese Standard | P59 | | Word Count Estimation | 40,470 | | Date of Issue | 2019-06-04 | | Date of Implementation | 2019-10-01 | | Regulation (derived from) | Natural Resources Department Announcement No. 7 of 2019 | | Issuing agency(ies) | National Energy Administration | DL/T 5786-2019: (Hydraulic plastic concrete mix design procedure)---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Code for mix design of hydraulic plastic concrete
ICS 27.140
P 59
Record number. 63143-2018
People's Republic of China Electric Power Industry Standard
P DL/T 5786-2019
Design specification for mix proportion of hydraulic plastic concrete
2019-06-04 released
2019-10-01 implementation
Issued by National Energy Administration
Foreword
This Regulation is based on the "Notice of the National Energy Administration on Issuing the First Batch of Industry Standards (Revision) Plans in the Energy Sector in.2013"
(Guoneng Technology [2013] No. 235).
In the process of compiling this regulation, extensive investigations, studies and special tests have been carried out, and the mix ratio of plastic concrete at home and abroad has been summarized.
The design method and test data of the company absorb the latest research results of plastic concrete and refer to the relevant content of relevant standards.
The main technical contents of this regulation include. basic regulations; raw materials; preparation strength and basic parameters; determination of mix ratio.
This regulation was proposed by the China Electricity Council.
This regulation is under the jurisdiction of the Hydropower Construction Standardization Technical Committee of the Electric Power Industry.
The main author of this regulation. China Gezhouba Group Co., Ltd.
Gezhouba Group Testing and Inspection Co., Ltd.
The main writers of this regulation. Zhang Zhenyu, Chen Weilie, Zhu Shengmin, Jiang Juanmei, Jinyou, Chen Zhiyuan, Wu Weijian
Nie Weiping Xu Na Zeng Wei Wang Jin Shi Xiaogang Zhu Huirong
Main reviewers of this regulation. Sun Laicheng, Ji Guojin, Wang Yi, Chu Yuexian, Mei Jinyu, Gao Xiang, Zhang Hong
Li Zhigang Wu Gao meets Wu Xu Wang Jun Zhong Yanxiang Yang Tao He Xiaoxiong
Yao Fuhai Lin Peng Zhu Star Lu Zhilin Tan Kaiyan Ding Kai Wang Pengyu
Cheng Zhihua Lu Qian
If you have any comments and suggestions during the implementation of this regulation, please feedback to the Standardization Management Center of the China Electricity Council (Address.
No. 1, Ertiao, Baiguang Road, Beijing, Postal Code. 100761)
Table of contents
1 General...1
2 Terms and Symbols...2
2.1 Terminology...2
2.2 Symbols...2
3 Basic regulations...3
4 Raw materials...4
5 Preparation strength and basic parameters...5
6 Determination of mix ratio...7
6.1 Calculation...7
6.2 Trial, adjustment and confirmation...7
Explanation of terms used in this regulation...8
List of Reference Standards...9
Article description...10
1 General
1.0.1 In order to standardize the design of plastic concrete mix ratio for hydropower and water conservancy projects, this specification is formulated.
1.0.2 This regulation is applicable to hydropower and water conservancy projects.
1.0.3 The mix ratio design of plastic concrete shall not only comply with this regulation, but also comply with the current relevant national standards.
2 Terms and symbols
2.1 Term
2.1.1 plastic concrete
The high-fluidity concrete mixed with bentonite, clay and other materials has low cement content, low strength and low elastic modulus.
2.1.2 cementing material
In the composition of plastic concrete, the general term for fine-grained raw materials such as cement, bentonite, clay, and fly ash.
2.1.3 Water-binder ratio
The mass ratio of mixing water and cementitious material in plastic concrete.
2.2 Symbols
f cu 0, --The compounding strength of concrete, MPa;
f kcu, --the standard value of cubic compressive strength of concrete for design age, MPa;
t--Probability coefficient;
Cv-the dispersion coefficient of intensity;
P--Concrete strength guarantee rate, %.
3 Basic regulations
3.0.1 Prior to the design of the plastic concrete mix ratio, the origins of raw materials such as cementitious materials, admixtures, sand and gravel aggregates and mixing water should be collected,
Variety, quality and other information, if necessary, conduct tests.
3.0.2 When designing the plastic concrete mix ratio, relevant engineering design data should be collected to clarify the following design requirements;
1 Concrete strength grade and strength guarantee rate;
2 The elastic modulus, permeability drop, permeability coefficient and other performance indicators of concrete;
3 The workability of concrete;
4 Maximum particle size of aggregate;
5 Other requirements.
3.0.3 When designing the plastic concrete mix ratio, the mix ratio parameters should be selected and selected according to the performance of the raw materials and the technical requirements of the concrete.
Calculate and determine after trial matching and adjustment in the laboratory. The mix ratio determined by the indoor test should be based on site conditions and economy.
Necessary adjustments.
3.0.4 Plastic concrete with special design requirements shall be subject to special demonstration.
4 raw materials
4.0.1 Cement, fly ash and other mineral admixtures, aggregates, admixtures and mixing water used for plastic concrete shall comply with the current industry standard "Water
The requirements of DL/T 5144 in the Construction Code for Industrial Concrete.
4.0.2 The quality of bentonite and clay for plastic concrete shall conform to the current industry standard "Construction Rules for Concrete Impervious Walls of Hydropower and Water Conservancy Engineering
Fan" DL/T 5199.
4.0.3 Medium-coarse sand should be used for plastic concrete, and the maximum size of coarse aggregate should not be greater than 20mm. When the maximum particle size of coarse aggregate is greater than 20mm,
The amount of aggregate larger than 20mm should not exceed 50% of the amount of coarse aggregate, and the maximum particle size shall not exceed 40mm.
5 Preparation strength and basic parameters
5.0.1 The mixed strength of plastic concrete is calculated according to formula (5.0.1-1).
5.0.2 Orthogonal test design method should be adopted for the design of plastic concrete mix ratio, and the test factors should at least consider the water-binder ratio and the amount of bentonite.
The water-binder ratio and the amount of bentonite can be selected according to the standard value of concrete design age strength according to Table 5.0.2.
5.0.3 The sand ratio of plastic concrete should not be less than 45%, the amount of cement should not be less than 80kg/m3, and the amount of bentonite should not be less than 40kg/m3.
The total amount of cementitious materials should not be less than 240kg/m3.When blended with fly ash, the blending amount should be 10%-30%. When mixed with other admixtures, its
The dosage should be determined by experiment.
5.0.4 Plastic concrete should be mixed with water reducing agent and air-entraining agent. The dosage of water reducing agent should be determined according to the recommended dosage of the manufacturer and determined through experiments.
The dosage of the agent should be determined according to the gas content of the mixture. The air content of plastic concrete should not exceed 7%.
5.0.5 The water consumption for plastic concrete should be (260～320) kg/m3 when the maximum particle size of coarse aggregate is 20mm.
When it is 40mm, it should be (240～300)kg/m3.
6 Determination of mix ratio
6.1 Calculation
6.1.1 The calculation of the plastic concrete mix ratio shall be based on the saturated surface dry state aggregate.
6.1.2 The strength standard value of the plastic concrete design age refers to a cube test with a side length of 150mm made and cured according to the standard method.
For pieces, the compressive strength with the design guarantee rate measured by the standard test method at the design age, in N/mm2 or MPa.
6.1.3 The calculation method for the amount of each material of plastic concrete shall be in accordance with the current industry standard "Design Regulations for Mixture Ratio of Hydraulic Concrete" DL/T
5330 execution.
6.2 Trial, adjustment and confirmation
6.2.1 The actual raw materials of the project should be used for the trial matching of plastic concrete mix. The mixing of plastic concrete should adopt a forced mixer,
Other requirements shall be carried out in accordance with the current industry standard "Test Regulations for Hydraulic Plastic Concrete" DL/T 5303.
6.2.2 The minimum mixing amount of the plastic concrete trial mix shall meet the requirements of Table 6.2.2.When mechanical mixing is used, the mixing amount should not be small
It is 1/4 of the rated mixing volume of the mixer.
6.2.3 Calculate the mix ratio and perform trial mixing. According to the workability of the plastic concrete mixture, the preliminary determined water consumption, sand ratio, and external
Properly adjust the dosage of additives, etc., and propose the mixing ratio for testing.
6.2.4 Carry out relevant performance tests in accordance with DL/T 5303, and propose plastic concrete mix ratios that meet various performance requirements.
6.2.5 The adjustment and determination of the plastic concrete mix ratio shall be implemented in accordance with DL/T 5330.
Explanation of terms used in this regulation
1 In order to facilitate the differentiated treatment in the implementation of the provisions of this regulation, the terms with different strictness requirements are explained as follows.
1) The expression is very strict and must be done.
Use "must" for positive words and "forbidden" for negative words;
2) Indicates strict, which should be done under normal circumstances.
Use "should" for positive words, and "should" or "must not" for negative words;
3) Indicates that a slight choice is allowed, and this should be done first when conditions permit.
The positive word is "suitable", and the negative word is "not suitable";
4) It means that there is a choice, and if this can be done under certain conditions, "Yes" is used.
2 The terms specified in the clause that should be implemented in accordance with other relevant standards are. "shall comply with the regulations of.." or "shall be implemented in accordance with.".
List of Reference Standards
1 "Specification for Hydraulic Concrete Construction" DL/T 5144
2 "Construction Code for Concrete Impervious Walls of Hydropower and Water Conservancy Projects" DL/T 5199
3 "Test Regulations for Hydraulic Plastic Concrete" DL/T 5303
4 "Specifications for design of hydraulic concrete mix ratio" DL/T 5330
People's Republic of China Electric Power Industry Standard
Design specification for mix proportion of hydraulic plastic concrete
Article description
Formulate instructions
This regulation is based on the "Notice of the National Energy Administration on Issuing the First Batch of Industry Standard System (Revision) Plans in the Energy Sector in.2013"
(Guoneng Technology [2013] No. 235).
In the process of compiling this regulation, extensive investigation and research and data collection were carried out, and the distribution of plastic concrete at home and abroad was carefully summarized.
The combined design method and testing data absorb the latest research results of plastic concrete and refer to the relevant content of the relevant specifications.
In order to facilitate the relevant personnel of the majority of design, construction, scientific research, schools and other units to correctly understand and implement the regulations when using this regulation
According to the provisions of the “Design Regulations for Hydraulic Plastic Concrete Mixture Ratio”, the authoring team compiled the regulations of this regulation in the order of chapters, sections and clauses for use
User reference.
This article states that it does not have the same legal effect as the standard text, and it is only used as a reference for users to understand and grasp the standards.
Table of contents
1 General...13
3 Basic regulations...14
4 Raw materials...15
5 Preparation strength and basic parameters...17
1 General
1.0.2 This design specification is applicable to bentonite plastic concrete and bentonite-clay plastic concrete.
3 Basic regulations
3.0.1 The origin, variety and quality of raw materials have an important influence on the performance of plastic concrete and the choice of mix parameters. Therefore,
Relevant data should be collected before the design of the mix ratio, and tests should be carried out if necessary. content include.
1 The variety, quality, strength grade, density, etc. of cement;
2 The origin, variety and quality of bentonite and clay;
3 The variety, quality, density, etc. of the admixture;
4 Types and quality of additives;
5 Coarse aggregate lithology, type, gradation, apparent density, water absorption, etc.;
6 Fine aggregate lithology, type, gradation, apparent density, fineness modulus, stone powder content, water absorption, etc.;
7 Quality of mixing water.
3.0.3 The mixing method of plastic concrete is basically the same as that of ordinary concrete, except that the mixing of clay and bentonite is added. Bentonite and clay
The soil mixing method is divided into two types. wet mixing and dry mixing. wet mixing is to make bentonite or clay into a slurry, and then add it to concrete.
Make a slurry 24 hours in advance; dry blending is to dry the bentonite or clay and add it to the concrete after sieving. Clay generally becomes
It is lumpy and has different moisture content, so it is not easy to be stirred in dry blending, so it is generally made into mud and blended in the form of mud. When preparing indoors,
Since the slurry should be prepared 24 hours in advance, it is difficult to find a suitable container in the room when the amount of mixing is large, and the uniformity of the slurry also affects the coagulation
The accuracy of the soil mixing ratio is easier to dry and sieving the clay. Therefore, dry mixing is generally used indoors. The bentonite particles are finer,
Easy to disperse, therefore, dry blending is generally used.
The mix ratio calculation of plastic concrete is the same as that of ordinary concrete, and the assumed mass method should be used when there is no apparent density of related materials.
According to calculation, the quality of concrete can be taken as (2250±100) kg/m3, and the water content in the raw materials should be deducted.
3.0.4 The compressive strength of plastic concrete is generally 1.0 MPa ~ 5.0 MPa, the elastic modulus is generally not more than.2000 MPa, and the elastic strength ratio is 100 ~
500, the permeability coefficient is generally between m×10-6 and m×10-8.However, due to geological conditions, design water level and other factors, some projects
The design index often exceeds the above range. For example, the 28d design compressive resistance of the concrete cut-off wall at the fracture zone of the dam foundation of the Xiangjiaba dam foundation
The strength requirement is 7.5MPa～10.0MPa, the elastic-strength ratio is less than 500, and the permeability coefficient is less than or equal to 10-8, which is much higher than the requirements of general plastic concrete impervious walls.
Special demonstration should be carried out for this kind of plastic concrete with special design requirements.
4 raw materials
4.0.1 In general, the type of cement used should be determined according to the design requirements and combined with local raw materials, and the strength grade should be selected
32.5 MPa and above ordinary Portland cement, slag cement or fly ash Portland cement, high strength grade can be selected if possible
Of cement. At present, ordinary Portland cement and slag Portland cement are mostly used, and composite Portland cement and fly ash Portland cement are also used.
There is a small amount of use, if pozzolanic Portland cement is used, its applicability must first be determined.
The strength of plastic concrete mainly comes from the gelation effect of the hydration of the cementitious material itself. Therefore, increasing the amount of cement can increase
The compressive strength, splitting tensile strength and shear strength of plastic concrete have been proved by experiments that under the same amount of cement and bentonite,
The selection of high-strength cement is beneficial to increase the strength of plastic concrete.
When the sulfate content in the groundwater reaches the weak corrosion level or above, it will have crystallinity to the cement when the sulfate reacts with the cement
Corrosion, cracking, disintegration and loss of strength will occur. Therefore, sulfate-resistant cement or fly ash should be appropriately added to improve the mixing
The feasibility of the anti-erosion performance of concrete needs to be determined by experiment.
At present, high-quality fly ash of grade II and above is often mixed in plastic concrete. Fly ash has morphological effect, filling effect and micro-aggregate
Effect, increase the workability of the mixture, the Ca(OH)2 produced by cement hydration grows directionally in the transition interface zone between the slurry and the aggregate, and makes
The thickness of the transition interface area increases, and the fly ash blended has a pozzolanic effect, and it reacts with Ca(OH) to form calcium silicate hydrate.
Improve the performance of the transition interface zone between the slurry and the aggregate, reduce the thickness of the transition interface zone, and increase the bonding strength between the slurry and the aggregate.
The hydrated calcium silicate produced by the secondary hydration of fly ash fills the gaps of the concrete, which can improve the pore structure inside the concrete and make the concrete
It is more dense and solid, which helps to improve the later strength and performance of concrete. When the groundwater contains a large amount of sulfate, fly ash should be added appropriately,
It can improve the corrosion resistance of concrete, and its feasibility needs to be determined by experiments.
Plastic concrete can also be mixed with slag, pozzolan and other mineral admixtures, and its quality should meet the requirements of the corresponding standards.
It is advisable to use air-entraining water-reducing agent in plastic concrete, or compounding water-reducing agent and air-entraining agent, and playing the role of water-reducing agent and air-entraining agent at the same time.
This can effectively reduce water consumption, reduce water-binder ratio, reduce the generation of micro-pores in plastic concrete after molding, and improve concrete
Density, introduce tiny closed bubbles, increase the workability of the mixture, block the internal communication channels of the concrete, and improve the concrete
Pore structure improves the durability of concrete such as frost resistance and impermeability. In addition, air-entraining water reducing agent or compounding water reducing agent and air-entraining agent can reduce
The modulus of elasticity has a significant effect, and ordinary water reducing agents have a certain effect on water reduction, but the effect of compressive strength, elastic modulus and impermeability is not clear enough.
Show.
4.0.2 At present, there is no special bentonite specification for the electric power industry, "Specification for Construction of Concrete Impervious Walls for Hydropower and Water Conservancy Projects" DL/T
According to 5199-2004, the quality of commodity bentonite can be implemented in accordance with "Bentonite for Drilling Fluid" SY/T 5060.This standard is for petroleum industry
The current standard number is SY/T 5060-1993.The current national standard "Bentonite" GB/T 20973-2007 divides bentonite into
There are three types of bentonite for foundry, bentonite for metallurgical pellets, and bentonite for drilling mud. Among them, there are three types of bentonite for drilling mud.
Drilling bentonite, untreated bentonite and OCMA bentonite are slightly different from SY/T 5060 in specific regulations. "Water Conservancy and Hydroelectrician
The quality of commercial bentonite specified in “Code for Construction of Long-range Concrete Impervious Walls” SL 174-2014 can be in accordance with “Code for Drilling Fluid Materials” GB/T 5005
Regulations are implemented. The current standard number of this standard is GB/T 5005-2010, and its regulations are consistent with GB/T 20973-2007 Bentonite Regulations for Drilling Mud
Set the same. However, considering the consistency with the current specification and the specification will continue to be updated, this standard still stipulates that the quality of bentonite shall be in accordance with DL/T 5199
carried out. At present, in order to ensure the quality of hydropower and water conservancy projects, all bentonites used are finished products produced by regular manufacturers, which can be produced as required.
Production and control.
Compared with bentonite, clay has a lower cost and has less impact on the strength of plastic concrete, but high-quality clay has an impermeability to plastic concrete
The effect is greater. Clay generally needs to be processed before it can be used. When blending, it must be dried, crushed and passed through a 4.75mm square hole.
Otherwise, the agglomerated clay will not be easily dispersed during mixing, which will affect the uniformity of the concrete quality and affect the strength and impermeability of the plastic concrete.
To adversely affect.
4.0.3 The strength of plastic concrete mixed with bentonite is low, and the aggregate is generally not damaged when it is damaged, so the strength of the aggregate affects it
Not big, but to meet the low elastic modulus index requirements, the particle size of the stone particles must be strictly controlled. It is recommended to use a single continuous gradation of 5～20mm
For stones, the smaller the aggregate particle size, the larger the specific surface area. When the amount of slurry and aggregate is the same, the contact area between slurry and aggregate is
This increases the strength of the interface between the paste and the aggregate, and the force in the interface area is also more uniform, which improves the plastic concrete
The overall performance of the plastic concrete will increase significantly if coarse aggregates with larger particle sizes are used.
5 Preparation strength and basic parameters
5.0.1 There are two methods for calculating the strength of concrete construction mix. the mean square deviation (σ) method and the dispersion coefficient (Cv) method. In recent years, domestic
Most codes use the mean square error method. The reason why this code recommends the dispersion coefficient method is based on the following reasons. First, plastic mixing
The compressive strength of concrete is very low, generally 1 MPa ~ 5 MPa, the existing relevant specifications are not applicable; secondly, the clay mixed in the concrete
And bentonite are manufactured products of natural minerals, which cause the dispersion of concrete strength to be large, and the dispersion can be judged intuitively by the Cv value
the size of. The data in Table 5.0.1-2 are quoted from "Specification for Construction of Concrete Impervious Walls of Hydropower and Water Conservancy Projects" DL/T 5199-2004.
5.0.2 Unlike ordinary concrete mix design, for the three indicators of plastic concrete performance, the modulus of elasticity is that of concrete
The main design indicators and characteristics, and elastic modulus and compressive strength are a pair of contradictions that are not easy to reconcile, so the plastic concrete mix ratio is set
The meter generally has two main design lines, namely, the compressive strength and elastic modulus are both the control indicators, and the permeability coefficient index requirements are taken into consideration. Infiltrate
The permeability coefficient can easily meet the design requirements. The amount of cement and bentonite and the ratio between them have a greater impact on the strength and elastic modulus.
The increase in the amount increases the strength and elastic modulus; the increase in the amount of bentonite decreases the strength and elastic modulus. Therefore, the two should be found through experiments.
Appropriate dosage and proportional relationship.
The compressive strength and impermeability indexes of plastic concrete are not contradictory, that is, the permeability coefficient decreases as the compressive strength increases, and both
The goal is easy to achieve together, but the contradiction between the strength and the elastic modulus will inevitably lead to the contradiction between the elastic modulus and the permeability coefficient.
This increases the permeability coefficient as a control index, that is, the elastic modulus and compressive strength meet the design requirements but the permeability coefficient cannot.
Case. The focus of solving the above-mentioned con...
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