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GB 50496-2018 English PDF (GB50496-2018)
GB 50496-2018 English PDF (GB50496-2018)
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GB 50496-2018: Code for construction of mass concrete
GB/T 50496-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC
P GB/T 50496-2018
Standard for construction of mass concrete
ISSUED ON. APRIL 25, 2018
IMPLEMENTED ON. DECEMBER 01, 2018
Issued by. Ministry of Housing and Urban-Rural Development of PRC.
State Administration for Market Regulation.
Table of Contents
Foreword... 5
1 General provisions... 8
2 Terms and symbol... 8
2.1 Terms... 8
2.2 Symbol... 10
3 Basic requirements... 13
4 Materials, mix proportioning, production and transportation... 14
4.1 General requirements... 15
4.2 Materials... 15
4.3 Design of mix proportioning... 16
4.4 Production and transportation... 17
5 Construction... 18
5.1 General requirements... 18
5.2 Technology preparation... 19
5.3 Formwork... 20
5.4 Placing... 20
5.5 Curing... 21
5.6 Construction in special climate... 22
5.7 Sampling in site... 23
6 Temperature monitor and control... 23
Appendix A Computing method for concrete pump output and carriers... 26
Appendix B Computing method of thermal stress and shrinkage stress during
construction of mass concrete... 27
Appendix C Computing method of insulation layer thickness of mass concrete... 37
Explanation of wording in this standard... 40
List of quoted standards... 41
Standard for construction of mass concrete
1 General provisions
1.0.1 This standard is formulated in order to implement national technical and economic
policies in mass concrete construction, ensure project quality, achieve advanced
technology, reasonable process, resource saving, environment protection.
1.0.2 This standard applies to mass concrete construction in concrete structures. It is
not applicable to the construction of roller compacted concrete and hydraulic mass
concrete.
1.0.3 In addition to complying with this standard, mass concrete construction shall also
comply with the relevant current national standards.
2 Terms and symbol
2.1 Terms
2.1.1 Mass concrete
A large volume concrete which has a minimum physical dimension of not less than 1
m, OR concrete which is expected to cause harmful cracks due to temperature changes
and shrinkage caused by hydration of the cementitious materials in the concrete.
2.1.2 Cementitious material
A general term for Portland cement and active mineral admixtures used to prepare
concrete.
2.1.3 Alternative bay construction method
A construction method, that divides an extra-long concrete block into several small
blocks for construction at intervals, then connects the several small blocks into a whole
after a short-term stress release. It relies on the tensile strength of the concrete to resist
the temperature shrinkage stress of the lower section.
2.1.4 Permanent deformation seam
Permanently reserved joints that divide buildings (structures) vertically, including
expansion joints and settlement joints.
t - Age of concrete;
Ts - Surface temperature of placed concrete block;
Tb(t) - Surface temperature of the placed concrete block at the age t;
Tbm(t), Tdm(t) - When the middle part of the placed concrete block reaches the highest
temperature, the temperature of the upper and lower surface layers of the block;
Tmax - The maximum temperature inside the placed concrete block;
Tmax(t) - The maximum temperature in the placed concrete block at the age t;
Tq - The average temperature of the atmosphere at which the concrete reaches its
maximum temperature;
T(t) - The adiabatic temperature rise of concrete at the age of t;
Ty(t) - The equivalent shrinkage temperature of concrete at the age of t;
Tw(t) - The expected stable temperature or final stable temperature of the placed
concrete block at the age of t;
ΔT1(t) - The temperature difference of core and surface of the concrete pouring block,
at the age of t;
ΔT2(t) - The comprehensive cooling difference of the concrete pouring block during
the cooling process, at the age of t;
ΔT1max(t) - The maximum possible temperature difference between inside and
outside after concrete pouring;
ΔT1i(t) - The increment of the temperature difference of core and surface of the
concrete pouring block, in the i-th calculation section at the age of t;
ΔT2i(t) - The increment of the comprehensive cooling difference of the concrete
pouring block, in the i-th calculation section at the age of t;
βµ - Heat release coefficient of solid in air;
βs - Total heat release coefficient of insulation material;
λ0 - Thermal conductivity of concrete;
λi - Thermal conductivity of the i-th layer of insulation material.
2.2.2 Quantitative geometric parameters
H - The thickness of the placed concrete block, which is the sum of the actual
4 Technical measures shall be taken to reduce the external constraints of mass
concrete in the design;
5 In the design, relevant testing requirements for temperature field and strain shall
be put forward based on the engineering conditions.
3.0.3 Before the construction of mass concrete, the temperature, temperature stress and
shrinkage stress of the placed concrete block shall be trial calculated; the peak value of
rising temperature of the placed concrete block, the control indicators of the
temperature difference of core and surface, the descending speed of temperature shall
be determined; corresponding technical measures for temperature control shall be
formulated.
3.0.4 The temperature control indicators for mass concrete construction shall comply
with the following requirements.
1 The temperature rise of the placed concrete block based on the temperature of
mixture placing to mold should not be greater than 50 °C;
2 The temperature difference of core and surface of the placed concrete block
(excluding the equivalent temperature of concrete shrinkage) should not be
greater than 25 °C;
3 The descending speed of temperature of the placed concrete block should not be
greater than 2.0 °C/d;
4 When removing the thermal insulation cover, the temperature difference between
the surface of the placed concrete block and the atmosphere shall not be greater
than 20 °C.
3.0.5 Before constructing mass concrete, it shall make construction preparations;
contact the local meteorological observatories and stations to understand recent
meteorological conditions. During winter construction, it shall also comply with the
relevant winter construction provisions for concrete.
3.0.6 Mass concrete construction shall adopt energy-saving, material-saving, water-
saving, land-saving, environmental protection measures. It shall comply with the
relevant provisions of the current national standard "Code for green construction of
building" GB/T 50905.
4 Materials, mix proportioning, production and
transportation
4.1 General requirements
4.1.1 In addition to meeting the design requirements for strength grade, durability,
impermeability, volume stability, the mass concrete's mix proportion design shall also
meet the requirements for mass concrete construction technology; it shall use materials
rationally and reduce the adiabatic temperature rise of concrete.
4.1.2 The preparation and transportation of mass concrete shall not only meet the
requirements of the concrete design strength grade, but also adjust the relevant
parameters of the ready-mixed concrete, according to the ready-mixed concrete supply
transportation distance, transportation equipment, supply capacity, material batch,
ambient temperature, etc.
4.2 Materials
Get QUOTATION in 1-minute: Click GB 50496-2018
Historical versions: GB 50496-2018
Preview True-PDF (Reload/Scroll if blank)
GB 50496-2018: Code for construction of mass concrete
GB/T 50496-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC
P GB/T 50496-2018
Standard for construction of mass concrete
ISSUED ON. APRIL 25, 2018
IMPLEMENTED ON. DECEMBER 01, 2018
Issued by. Ministry of Housing and Urban-Rural Development of PRC.
State Administration for Market Regulation.
Table of Contents
Foreword... 5
1 General provisions... 8
2 Terms and symbol... 8
2.1 Terms... 8
2.2 Symbol... 10
3 Basic requirements... 13
4 Materials, mix proportioning, production and transportation... 14
4.1 General requirements... 15
4.2 Materials... 15
4.3 Design of mix proportioning... 16
4.4 Production and transportation... 17
5 Construction... 18
5.1 General requirements... 18
5.2 Technology preparation... 19
5.3 Formwork... 20
5.4 Placing... 20
5.5 Curing... 21
5.6 Construction in special climate... 22
5.7 Sampling in site... 23
6 Temperature monitor and control... 23
Appendix A Computing method for concrete pump output and carriers... 26
Appendix B Computing method of thermal stress and shrinkage stress during
construction of mass concrete... 27
Appendix C Computing method of insulation layer thickness of mass concrete... 37
Explanation of wording in this standard... 40
List of quoted standards... 41
Standard for construction of mass concrete
1 General provisions
1.0.1 This standard is formulated in order to implement national technical and economic
policies in mass concrete construction, ensure project quality, achieve advanced
technology, reasonable process, resource saving, environment protection.
1.0.2 This standard applies to mass concrete construction in concrete structures. It is
not applicable to the construction of roller compacted concrete and hydraulic mass
concrete.
1.0.3 In addition to complying with this standard, mass concrete construction shall also
comply with the relevant current national standards.
2 Terms and symbol
2.1 Terms
2.1.1 Mass concrete
A large volume concrete which has a minimum physical dimension of not less than 1
m, OR concrete which is expected to cause harmful cracks due to temperature changes
and shrinkage caused by hydration of the cementitious materials in the concrete.
2.1.2 Cementitious material
A general term for Portland cement and active mineral admixtures used to prepare
concrete.
2.1.3 Alternative bay construction method
A construction method, that divides an extra-long concrete block into several small
blocks for construction at intervals, then connects the several small blocks into a whole
after a short-term stress release. It relies on the tensile strength of the concrete to resist
the temperature shrinkage stress of the lower section.
2.1.4 Permanent deformation seam
Permanently reserved joints that divide buildings (structures) vertically, including
expansion joints and settlement joints.
t - Age of concrete;
Ts - Surface temperature of placed concrete block;
Tb(t) - Surface temperature of the placed concrete block at the age t;
Tbm(t), Tdm(t) - When the middle part of the placed concrete block reaches the highest
temperature, the temperature of the upper and lower surface layers of the block;
Tmax - The maximum temperature inside the placed concrete block;
Tmax(t) - The maximum temperature in the placed concrete block at the age t;
Tq - The average temperature of the atmosphere at which the concrete reaches its
maximum temperature;
T(t) - The adiabatic temperature rise of concrete at the age of t;
Ty(t) - The equivalent shrinkage temperature of concrete at the age of t;
Tw(t) - The expected stable temperature or final stable temperature of the placed
concrete block at the age of t;
ΔT1(t) - The temperature difference of core and surface of the concrete pouring block,
at the age of t;
ΔT2(t) - The comprehensive cooling difference of the concrete pouring block during
the cooling process, at the age of t;
ΔT1max(t) - The maximum possible temperature difference between inside and
outside after concrete pouring;
ΔT1i(t) - The increment of the temperature difference of core and surface of the
concrete pouring block, in the i-th calculation section at the age of t;
ΔT2i(t) - The increment of the comprehensive cooling difference of the concrete
pouring block, in the i-th calculation section at the age of t;
βµ - Heat release coefficient of solid in air;
βs - Total heat release coefficient of insulation material;
λ0 - Thermal conductivity of concrete;
λi - Thermal conductivity of the i-th layer of insulation material.
2.2.2 Quantitative geometric parameters
H - The thickness of the placed concrete block, which is the sum of the actual
4 Technical measures shall be taken to reduce the external constraints of mass
concrete in the design;
5 In the design, relevant testing requirements for temperature field and strain shall
be put forward based on the engineering conditions.
3.0.3 Before the construction of mass concrete, the temperature, temperature stress and
shrinkage stress of the placed concrete block shall be trial calculated; the peak value of
rising temperature of the placed concrete block, the control indicators of the
temperature difference of core and surface, the descending speed of temperature shall
be determined; corresponding technical measures for temperature control shall be
formulated.
3.0.4 The temperature control indicators for mass concrete construction shall comply
with the following requirements.
1 The temperature rise of the placed concrete block based on the temperature of
mixture placing to mold should not be greater than 50 °C;
2 The temperature difference of core and surface of the placed concrete block
(excluding the equivalent temperature of concrete shrinkage) should not be
greater than 25 °C;
3 The descending speed of temperature of the placed concrete block should not be
greater than 2.0 °C/d;
4 When removing the thermal insulation cover, the temperature difference between
the surface of the placed concrete block and the atmosphere shall not be greater
than 20 °C.
3.0.5 Before constructing mass concrete, it shall make construction preparations;
contact the local meteorological observatories and stations to understand recent
meteorological conditions. During winter construction, it shall also comply with the
relevant winter construction provisions for concrete.
3.0.6 Mass concrete construction shall adopt energy-saving, material-saving, water-
saving, land-saving, environmental protection measures. It shall comply with the
relevant provisions of the current national standard "Code for green construction of
building" GB/T 50905.
4 Materials, mix proportioning, production and
transportation
4.1 General requirements
4.1.1 In addition to meeting the design requirements for strength grade, durability,
impermeability, volume stability, the mass concrete's mix proportion design shall also
meet the requirements for mass concrete construction technology; it shall use materials
rationally and reduce the adiabatic temperature rise of concrete.
4.1.2 The preparation and transportation of mass concrete shall not only meet the
requirements of the concrete design strength grade, but also adjust the relevant
parameters of the ready-mixed concrete, according to the ready-mixed concrete supply
transportation distance, transportation equipment, supply capacity, material batch,
ambient temperature, etc.
4.2 Materials
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