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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces YB/T 4184-2009 Technical specification for construction of steel slag mixture used as base course. The following main changes have been made with respect to YB/T 4184-2009:
——The standard name is changed to Technical specification for construction of steel slag mixture used as base course;
——The term “steel slag mixture” is revised, and terms “flue gas desulfurization gypsum” and “permitted delay time” are added;
——Industrial waste residues such as ground granulated blast furnace slag, refining slag, flue gas desulfurization gypsum and air-cooled hard slag are added in the requirements for raw materials to serve as the raw materials of mixture;
——The nominal maximum particle size, crushing value, specifications and other indicators of steel slag aggregate are adjusted; the test method for immersion expansion ratio is adjusted; the technical requirements for raw materials such as lime, fly ash and cement are revised; and the regulation that refining slag may be used to replace lime on Class II or below highways is added;
——Clause 4 is changed to composition design of steel slag mixture, in which technical requirements for the immersion expansion ratio of cement stabilized steel slag mixture, cement and fly ash stabilized steel slag mixture, lime and fly ash stabilized steel slag mixture and lime stabilized steel slag mixture are added, the technical requirements for 7d unconfined compressive strength of cement stabilized steel slag mixture, cement and fly ash stabilized steel slag mixture, lime and fly ash stabilized steel slag mixture and lime stabilized steel slag mixture are adjusted and the mixture composition design is added;
——The construction technology of steel slag mixture is revised;
——Clause 6 is changed from “Quality standard and inspection & acceptance” to “Construction quality standard and control”.
This standard was proposed by China Iron and Steel Industry Association.
This standard is under the jurisdiction of the SAC/TC 183 National Technical Committee on Steel of Standardization Administration of China.
The previous editions of this standard are as follows:
——YBJ 230-1991 and YB/T 4184-2009.
Technical specification for construction of steel slag mixture used as base course
1 General rules
1.0.1 This specification is formulated to promote the use of steel slag to build road base (including subbase, the same below), ensure the construction quality of steel slag mixture used as base course, and unify the construction and acceptance standards.
1.0.2 This specification is applicable to the construction and acceptance of the steel slag mixture used as base course of roads.
1.0.3 The steel slag aggregate referred to in this specification does not contain stainless steel slag, and the industrial waste residue or natural material used shall comply with the current relevant environmental protection regulations of the nation to avoid environmental pollution.
1.0.4 In addition to the requirements stipulated in this specification, the construction and acceptance of the steel slag mixture used as base course shall comply with the current relevant standards of the nation.
2 Terms
For the purposes of this specification, the terms given in YB/T 804 Terminology for iron and steel slag & treatment and utilization and the following apply.
2.0.1
base
main bearing course directly under the asphalt pavement surface or structural course directly under the cement concrete panel
2.0.2
subbase
secondary bearing course paved under the asphalt pavement base or auxiliary course paved under the cement concrete pavement base
2.0.3
flue gas desulfurization gypsum
flue gas desulfurization gypsum with calcium sulfate dihydrate (CaSO4·2H2O) as the main component, which is produced by desulfurization and purification of sulfur-containing flue gas by limestone/lime-gypsum wet method
2.0.4
steel slag aggregate
granulated steel slag which plays the role of skeleton and filling in the mixture
2.0.5
steel slag mixture
mixture obtained by mixing steel slag aggregate with a certain amount of inorganic binder (cement, lime, fly ash, ground granulated blast furnace slag, refining slag, flue gas desulfurization gypsum, etc.) or other materials (air-cooled hard slag, etc.) and a proper amount of water (usually the optimum water content). The amount of steel slag in the steel slag mixture shall not be less than 50% (mass ratio)
2.0.6
cement stabilized steel slag mixture
mixture obtained by mixing steel slag aggregate with a certain amount of cement and water, in which the cement may be replaced by ground granulated blast furnace slag
2.0.7
cement and fly ash stabilized steel slag mixture
mixture obtained by mixing steel slag aggregate with a certain amount of cement and fly ash and water, in which the cement may be replaced by ground granulated blast furnace slag
2.0.8
lime and fly ash stabilized steel slag mixture
mixture obtained by mixing steel slag aggregate with a certain amount of lime and fly ash or coal cinder and water, in which the fly ash may be replaced by coal cinder and the lime may be replaced by refining slag. Including lime and coal cinder stabilized steel slag mixture, fly ash stabilized steel slag mixture as well as lime and fly ash steel slag mixture
2.0.9
lime stabilized steel slag mixture
mixture obtained by mixing steel slag aggregate with a certain amount of lime or refining slag and water
2.0.10
immersion expansion ratio
volume change ratio of steel slag or steel slag mixture after immersion under specified test conditions
2.0.11
permitted delay time
maximum permitted time interval from the completion of cement stabilized material mixing to the start of rolling forming, on the premise of meeting the strength standard
3 Raw material requirements
3.1 General requirements
Where the raw materials given in this specification are used for other roads such as urban roads, they can be used by reference to the corresponding traffic classes of highways according to the traffic class requirements.
3.2 Steel slag aggregate
3.2.1 The immersion expansion ratio of the aggregate with steel slag as a base shall not be more than 2.0%, and the test method shall be in accordance with the "method for immersion expansion ratio" specified in GB/T 24175 Test method for stability of steel slag.
Where steel slag is used as coarse aggregate, the nominal maximum particle size shall not be greater than 31.5mm, and other technical indicators shall meet those specified in Table 3-1. The test methods for crushing value and content of elongated and flaky particles of coarse steel slag aggregate shall be in accordance with T0316 and T0312 in JTG E42 Test methods of aggregate for highway engineering.
Table 3-1 Technical requirements of coarse steel slag aggregate
Indicator Course Expressway and Class I highway Class II or below highways
Super-heavy, extra heavy traffic Heavy, medium and light traffic
Crushing value/% Base ≤22 ≤26 ≤35
Subbase ≤30 ≤30 ≤40
Content of elongated and flaky particles/% Base ≤18 ≤22 -
3.2.2 The specification requirements of coarse steel slag aggregate for base and subbase shall meet those specified in Table 3-2.
3.2.3 The specification requirements of fine steel slag aggregate shall meet those specified in in Table 3-3.
3.2.4 Single size materials shall be adopted as the coarse steel slag aggregate at 4.75mm above the base of super-heavy and extra heavy traffic load grade of expressways and Class I highways.
3.3 Air-cooled hard slag
3.3.1 The air-cooled hard slag may be used as the stabilized material of steel slag mixture base or subbase.
3.3.2 Where air-cooled hard slag is used as coarse aggregate, the crushing value, content of elongated and flaky particles and specifications shall meet the technical requirements in Table 3-1 and the specification requirements in Table 3-2.
Table 3-2 Specification requirements of coarse steel slag aggregate
Engineering Engineering particle size/mm Mass fraction (%) through the following sieve mesh (mm) Nominal size /mm
37.5 31.5 26.5 19.0 13.2 9.5 4.75 2.36
G2 20~30 100 90~100 - 0~10 0~5 - - - 19~31.5
G3 20~25 - 100 90~100 0~10 0~5 - - - 19~26.5
G4 15~25 - 100 90~100 - 0~10 0~5 - - 13.2~26.5
G5 15~20 - - 100 90~100 0~10 0~5 - - 13.2~19
G6 10~30 100 90~100 - - - 0~10 0~5 - 9.5~31.5
G7 10~25 - 100 90~100 - - 0~10 0~5 - 9.5~26.5
G8 10~20 - - 100 90~100 - 0~10 0~5 - 9.5~19
G9 10~15 - - - 100 90~100 0~10 0~5 - 9.5~13.2
G10 5~15 - - - 100 90~100 40~70 0~10 0~5 4.75~13.2
G11 G11 - - - - 100 40~70 0~10 0~5 4.75~9.5
Table 3-3 Specification requirements of fine steel slag aggregate
Specification Engineering particle size/mm Mass fraction (%) through the following sieve mesh (mm) Nominal size /mm
9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075
XG1 3~5 100 90~100 0~15 0~5 - - - - 2.36~4.75
XG2 0~3 - 100 90~100 - - - - 0~15 0~2.36
XG3 0~5 100 90~100 - - - - - 0~20 0~4.75
3.4 Cement and additive
3.4.1 The strength grade is 32.5 or 42.5 and the cement complying with this specification may be used.
3.4.2 The initial setting time of the cement used in the steel slag mixture shall be greater than 3h, and the final setting time shall be greater than 6h, but less than 10h.
3.4.3 When retarder or early strength agent is added to steel slag mixture, the mixture shall be tested for verification. The technical requirements of retarder and early strength agent shall comply with the requirements of JTG/T F30 Technical guidelines for construction of highway cement concrete pavements.
3.5 Ground granulated blast furnace slag
The ground granulated blast furnace slag meeting the technical requirements of GB/T 18046 Ground granulated blast furnace slag used for cement and concrete may be used as the binder of base or subbase of cement stabilized steel slag mixture.
3.6 Lime
3.6.1 The technical requirements of lime shall meet those specified in Table 3-4 and Table 3-5, and the test method shall be in accordance with JTG E51 Test methods of materials stabilized with inorganic binders for highway engineering.
Table 3-4 Technical requirements of quick lime
Indicator Calcium quick lime Magnesium quick lime
I II III I II III
Effective calcium oxide and magnesium oxide content/% ≥85 ≥80 ≥70 ≥80 ≥75 ≥65
Unslaked residue content/% ≤7 ≤11 ≤17 ≤10 ≤14 ≤20
Classification boundaries of calcium magnesium lime and magnesium oxide content/% ≤5 >5
Table 3-5 Technical requirements of hydrated lime
Indicator Calcium quick lime Magnesium quick lime
I II III I II III
Effective calcium oxide and magnesium oxide content/% ≥65 ≥60 ≥55 ≥60 ≥55 ≥50
Water content/% ≤4 ≤4 ≤4 ≤4 ≤4 ≤4
Fineness Residue on 0.60mm square-mesh sieve/% 0 ≤1 ≤1 0 ≤1 ≤1
Residue on 0.15mm square-mesh sieve/% ≤13 ≤20 - ≤13 ≤20 -
Classification boundaries of calcium magnesium lime and magnesium oxide content/% ≤4 >4
3.6.2 Lime used for expressways and Class I highways shall at least meet the technical requirements for Grade II lime, lime used for Class II highways shall at least meet the technical requirements for Grade III lime, and lime used for highways below Grade II should at least meet the technical requirements for Grade III lime.
3.6.3 The ground hydrated lime should be adopted for the base of expressways and Class I highways.
3.6.4 When refining slag is used to replace lime on the Class II or below highways, the strength of the mixture shall meet the requirements.
3.6.5 When offgrade lime is used in the highways below Class II, the effective calcium oxide content shall be more than 20%, and the strength of the mixture shall meet the requirements.
3.7 Fly ash
Dry or wet discharged silica-alumina fly ash and high calcium fly ash may be used as binder for base or subbase. The technical requirements of fly ash shall meet those specified in Table 3-6, and the test method shall be in accordance with JTG E51 Test methods of materials stabilized with inorganic binders for highway engineering.
Table 3-6 Technical requirements of fly ash
Item Technical requirements
Total content of SiO2, Al2O3 and Fe2O3/% ≥50
Ignition loss/% ≤20
Specific surface area/(m2/kg) ≥250
Residue on 0.3mm sieve/% ≤10
Residue on 0.075mm sieve/% ≤30
Water content of wet fly ash/% ≤35
The fly ash used in subbase of each class of highway and base of Class II or below highways shall be tested for the strength of mixture when its indicator of residue on sieve does not meet those specified in Table 3-6, and may only be used when the strength index required by this specification is reached.
3.8 Coal cinder
The maximum particle size of coal cinder used for building road base shall not be greater than 31.5mm, the total content of its main components SiO2, Al2O3 and Fe2O3 should not be less than 50%, and the ignition loss shall not be greater than 20%.
3.9 Flue gas desulfurization gypsum
The flue gas desulfurization gypsum conforming to the technical requirements of JC/T 2074 Flue gas desulfurization gypsum can be used as the binder of steel slag mixture base or subbase.
3.10 Water
3.10.1 Drinking water conforming to GB 5749 Standards for drinking water quality may be used for mixing and curing the materials of base and subbase.
3.10.2 Non-drinking water used as mixing water shall be subjected to water quality testing, the technical requirements shall meet those specified in Table 3-7, and the test method shall comply with JGJ 63 Standard of water for concrete.
3.10.3 The insoluble content of curing water may not be tested, and other indicators shall meet those specified in Table 3-7.
Table 3-7 Technical requirements of non-drinking water
Item Technical requirements
pH value ≥ 4.5
Cl- content (mg/L) ≤ 3,500
/(mg/L)
≤ 2,700
Alkali content (mg/L) ≤ 1,500
Soluble matter content (mg/L) ≤ 10,000
Insoluble matter content (mg/L) ≤ 5,000
Content of other impurities There shall be no floating grease and foam, obvious color and peculiar smell.
3.11 Other materials
3.11.1 If other industrial waste residues (such as tailings) are used, they shall pass the test verification.
3.11.2 For natural stones with steel slag mixture, the crushing value indicator, content of elongated and flaky particles and specification shall meet the technical requirements of coarse aggregate specified in 3.6 of JTG/T F20-2015 Technical guidelines for construction of highway roadbases.
4 Composition design of steel slag mixture
4.1 General requirements
4.1.1 In the composition design of mixture, the type and mix ratio of technologically and economically reasonable mixture shall be selected according to the design requirements.
4.1.2 The technical requirements of materials shall be determined according to highway class, traffic load grade, structural form, material type and other factors.
4.1.3 The composition design of steel slag mixture shall include four parts: raw material inspection, target mix ratio design of mixture, production mix ratio design of mixture and construction parameter determination.
4.1.4 Raw material inspection shall include the test of binder, stabilized material and other related materials. All testing indicators shall meet the requirements of relevant design standards or technical documents. The immersion expansion ratio of cement stabilized steel slag mixture, cement and fly ash stabilized steel slag mixture, lime and fly ash stabilized steel slag mixture and lime stabilized steel slag mixture shall not exceed 1.5%, and the immersion expansion ratio test shall be carried out according to the actual particle grading of the mixture. The test method is selected according to the method for immersion expansion ratio specified in GB/T 24175 Test method for stability of steel slag.
4.1.5 The base and subbase of steel slag mixture shall have enough strength and stability, small shrinkage (temperature shrinkage and dry shrinkage) deformation and strong anti-scouring capability; the freezing resistance of the base and subbase of steel slag mixture shall be tested in medium freezing and serious freezing areas.
4.1.6 The design of target mix ratio shall cover the following technical contents:
a) gradation range selection;
b) determination of the type and mix ratio of binders;
c) verification of the design and construction technical indicators related to the mixture.
4.1.7 The design of production mix ratio shall cover the following technical contents:
a) determination of the feeding ratio of silo;
b) determination of the permitted delay time of cement stabilized material;
c) determination of the calibration curve of binder dose;
d) determination of the optimum water content and maximum dry density of mixture.
4.1.8 The determination of construction parameters shall include the following technology contents:
a) determination of the binder dose;
b) determination of the reasonable water content and maximum dry density in construction;
c) verification of the strength technical indicator of mixture.
4.1.9 During the construction, the material composition shall be re-designed when the material quality or specification changes or the mixture variety changes.
4.1.10 The T0804 heavy compaction method in JTG E51 Test methods of materials stabilized with inorganic binders for highway engineering or the T0842 vibration compaction method should be adopted in the optimum water content and maximum dry density test for mixture. The T0843 specimen fabrication method should be adopted to form the unconfined compressive strength specimen of mixture.
4.2 Strength requirements
4.2.1 The steel slag mixture shall meet the strength requirements of this specification.
4.2.2 The 7d unconfined compressive strength shall be adopted as the main indicator for construction quality control of steel slag mixture.
4.2.3 For expressways and Class I highways, the relationship between 7d unconfined compressive strength of the used material to 90d or 180d unconfined compressive strength shall be verified.
4.2.4 The 7d unconfined compressive strength standard Rd of cement stabilized steel slag mixture shall meet those specified in Table 4-1.
Foreword i
1 General rules
2 Terms
3 Raw material requirements
3.1 General requirements
3.2 Steel slag aggregate
3.3 Air-cooled hard slag
3.4 Cement and additive
3.5 Ground granulated blast furnace slag
3.6 Lime
3.7 Fly ash
3.8 Coal cinder
3.9 Flue gas desulfurization gypsum
3.10 Water
3.11 Other materials
4 Composition design of steel slag mixture
4.1 General requirements
4.2 Strength requirements
4.3 Strength test and calculation
4.5 Recommended grading and technical requirements of steel slag mixture
4.6 Technical requirements for the design of target mix ratio of steel slag mixture
4.7 Technical requirements for design of mix ratio of steel slag mixture production
5 Construction
5.1 General
5.2 Centralized plant mixing and transportation of mixture
5.3 Artificial mixing of mixture
5.4 Paving and rolling by paver
5.5 Artificial paving and rolling
5.6 Curing method
5.7 Traffic control
5.8 Treatment between steel slag mixture courses
5.9 Treatment between steel slag mixture base and asphalt surface
5.10 Treatment of base shrinkage cracks
6 Construction quality standard and control
6.1 General
6.2 Material inspection
6.3 Paving of test sections
6.4 Testing during construction
6.5 Quality inspection
Annex A (Informative) Common mix ratio of steel slag mixture
Annex B (Normative) Recommended grading of steel slag mixture
