Heat of Hydration in Mass Concrete

Khaldoon Slaiai
Concrete Research Manager
Saudi Readymix Concrete company

HOH Basics – Mass Concrete Definition
Mass concrete is defined by ACI “Any volume of concrete with
dimensions large enough to require that measures be taken to
cope with generation of heat from hydration of the cement and
attendant volume change to minimize cracking.”
Examples:
• Dam
• Raft Foundation
• Pile Cap.
• Thick Wall.
• Thick column.
• Deep Slap.

Cement Composition “Type I - OPC”

Main Chemical Cement Reactions with Water

HOH generated from cement main ingredients

% of HOH generated from cement main ingredients

HOH Main Concerns
• Differential Temperature:
Crack Concern: Thermal Cracking
• Max Temperature:
 Durability Concern: DEF Cracking “DEF = Delayed Ettringite
Formation”
 Strength Concern : Effects on Ultimate Strength

Typical Temperature Curve in Mass Concrete
Placement
Temperature

Maximum Temperature (Tmax)
Maximum Temperature “Tmax” = Placement Temperature of
Concrete + Temperature Rise due to Heat of Hydration

Factors Affecting Maximum Temperature “Tmax” of
Concrete
 Cement Content.
 Type and source of cementitious materials.
 Section Thickness.
 Concrete Placing Temperature.
 Formwork and insulation.
 Ambient Temperature.
 Mix Design
 Mix Design
 Structural Design
 Supplier facility
 Contractor facility

Rate of Temperature Rise: Time of Occurrence of Tmax
Main Factors affecting:
 Cement Fineness and chemical composition.
 Cement Quantity
 Type of Cementitious materials added.
 Type of Admixture added.
 Structure Thickness.
 In general
the slower rate of temperature rise
the better to avoid the thermal cracking

Period required for Temperature dropping from the
maximum value
Main Factors affecting :
 Structure Thickness
 Type of Surface Insulation.

Durability Concern of Tmax “DEF Cracking”:
DEF may occur in mass concrete placement because the high internal temperature
(core temperature more than 70C). The mechanism appears to follow this sequence:
1. High Temperature disrupt the normal formation of ettringite causing the sulfate and
alumina to be adsorbed by CSH get in the cement paste.
2. After concrete has cooled to ambient conditions, the sulfate can later desorb in the
presence of moisture and react with calcium monomsulfoaluminate to form ettringite.
3. This “delayed” ettringite can then exert great pressure because if forms in the limited
space of a rigid structure in an expansive reduction.
4. Theses high pressures within the paste can cause internal micro-cracking and
macro-cracking.
The reformation of ettringite requires a
substantial quantity of water, without free
water the DEF reaction can not readily occur.

Strength Concern of Tmax “Reduction in Ultimate
Strength”:
It has been recognized
for many years that if
concrete is heated too
rapidly during the early
period of hydration,
the long term
properties may be
adversely affected.

Thermal Cracking
Thermal cracks occur when:
The tensile stress due to thermal stress is greater than The
tensile strength of concrete.
Thermal cracks occur when:
The thermal strain is greater than the tensile strain capacity
of the concrete
In other words

Thermal Strain formula
∝ 𝑐= 𝐶oefficient of thermal expansion of concrete
𝑯𝒊𝒈𝒉𝒆𝒓 ∝ 𝒄 → 𝑯𝒊𝒈𝒉𝒆𝒓 𝑺𝒕𝒓𝒂𝒊𝒏 → 𝑯𝒊𝒈𝒉𝒆𝒓 𝑪𝒓𝒂𝒄𝒌𝒊𝒏𝒈 𝑹𝒊𝒔𝒌
𝑯𝒊𝒈𝒉𝒆𝒓 ∆𝑻 → 𝑯𝒊𝒈𝒉𝒆𝒓 𝑺𝒕𝒓𝒂𝒊𝒏 → 𝑯𝒊𝒈𝒉𝒆𝒓 𝑪𝒓𝒂𝒄𝒌𝒊𝒏𝒈 𝑹𝒊𝒔𝒌

Temperature Differential ∆𝑻
Temperature gradients are produced when the heat being generated in
the concrete is dissipated to the surrounding environment causing the
temperature at the surface of the concrete to be lower than the
temperature at interior of the concrete

Differential Temperature (∆𝑻)
Differential Temperature (∆𝑻) = Max Temperature in Mass Structure –
Min Temperature in Mass structure AT ANY TIME
Internal restraint is a result of differential temperature
changes within an element.
It may lead to both surface cracking and internal cracking
that may not be observed from the surface.

Differential Temperature (∆𝑻)
Heating COOLING

Surface Thermal Cracking during Heating Period
 Since the temperature at the core of mass concrete is higher
due to the heat of hydration, expansion will occur.
 This expansion is restrained by the cooler exterior concrete
that doesn’t expand as rapidly as the core.
 The restraint will cause compressive stresses to develop at
the core and tensile stresses at the surface.
 It leads to increase the cracking potential at or close to the
surface of the concrete.
In Summary: As heating occurs, the surface
is subject to tensile stresses as the center
of the pour gets hotter and expands to a
greater extent.

Surface and/or Internal Thermal Cracking during Cooling
Period
As cooling occurs
There is a stress reversal and the surface cracks generally
reduce in width. At the same time tension is generated at the
center of the pour as it cools more than the surface and
internal cracking may occur.

∝ 𝒄= 𝑪𝐨𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐭 𝐨𝐟 𝐭𝐡𝐞𝐫𝐦𝐚𝐥 𝐞𝐱𝐩𝐚𝐧𝐬𝐢𝐨𝐧 𝐨𝐟 𝐜𝐨𝐧𝐜𝐫𝐞𝐭𝐞
A concrete with a low coefficient of thermal expansion
can significantly reduce the risk of thermal cracking
The value of αc can be estimated from the
coefficients of thermal expansion of the aggregates.

𝑪𝐨𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐭 𝐨𝐟 𝐭𝐡𝐞𝐫𝐦𝐚𝐥 𝐞𝐱𝐩𝐚𝐧𝐬𝐢𝐨𝐧 𝐨𝐟 some aggregate
Aggregate Type Thermal expansion coefficient
(microstrain/°C)
Quartzite 14
Gravel 13
Granite 10
Basalt 10
Limestone 9
Marble 7
Lytag (lightweight) 7

𝐋𝐨𝐰𝐞𝐫 𝐓𝐡𝐞𝐫𝐦𝐚𝐥 𝐒𝐭𝐫𝐚𝐢𝐧 → 𝐋𝐨𝐰𝐞𝐫 𝐑𝐢𝐬𝐤 𝐨𝐟 𝐭𝐡𝐞𝐫𝐦𝐚𝐥 𝐂𝐫𝐚𝐜𝐤𝐢𝐧𝐠
𝑳𝒐𝒘𝒆𝒓
𝑻𝒉𝒆𝒓𝒎𝒂𝒍
𝑺𝒕𝒓𝒂𝒊𝒏
∆𝑻
𝒂𝒏𝒅
/𝒐𝒓
𝑪𝐨𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐭
𝐨𝐟 𝐭𝐡𝐞𝐫𝐦𝐚𝐥
𝐞𝐱𝐩𝐚𝐧𝐬𝐢𝐨𝐧
Conclusion
To have same risk of thermal cracking: using concrete with lower coefficient
of thermal exemption allows more differential temperature to be applied

Effect of Aggregate Type on Tensile Strain Capacity of
Concrete
The tensile strain capacity is the
maximum strain that the
concrete can withstand without a
continuous crack forming.
The tensile strain capacity may
be measured directly or derived
from measurements of the
tensile strength and the elastic
modulus of the concrete

Allowable ∆𝑻 based on Aggregate Type
Source: CIRIA C660 Early-age thermal crack control in concrete
Worst Agg. Type
Agg. in ER & CR
NOT Available in
Saudi Arabia
(NOT used in
Concrete
Production in
SA)
Agg. in WR

Typical Limits usually specified in project Specifications
 The max temperature at any point within the pour shat not exceed 70 °C
WHY..….To avoid DEF and Negative affect on ultimate strength
 The max temperature differential “∆𝑻" shall not exceed 20 °C.
WHY…. To avoid thermal Cracking
WHY 20 °C: Designers at design stage usually have no idea about the
type of aggregate will be used in concrete so……..
They usually take in consideration the worst scenario which it is the use of
concrete with Gravel Aggregate which means the allowable ∆𝑻 is 20°C

Designers Point of View
It is recognized that at the design stage there may be limited information
available and a simplified design approach which uses conservative default
values is provided. This approach will lead to a conservative design.

Mean Methods for Controlling of Maximum Temperature
(𝑻𝐦𝐚𝐱)
Control Method Responsibility Restraints
Mix Design:
• Use the minimum amount
of Cement
• Use Cementitious
Additives at the right
percentage
Designer,
Consultant,
Contactor,
Supplier
• Specifying Minimum Cement content.
• Specifying strength at 28 days.
• Preventing the use of cementitious
additives by the contractor (Cost).
• Specifying special type of additives at
specified percentage.
Placing Temperature Contactor,
supplier
• Maximum temperature not specified in
the specification.
• Specifying unsuitable placing
temperature for thick structure such as
“32C”
• Contractor does not want to pay the
cost of Ice to be used for reducing the
placing temperature.
• Supplier does not have a facility to
produce low concrete temperature

Other Restraints may be affect the reduction of 𝑻𝐦𝐚𝐱
• Using Special Type of Formwork by contactor.
• Using concretive insulation layers for surface insulation due to
specifying concretive ∆𝑻 limit.
• High ambient temperature

Mean Methods for Control of (∆𝑻)
Control Method Responsibility Restraints
Reduce the heat loss from
concrete surface
Surface insulation “Applying
insulation layers”
Contactor • Cost of insulation layer.
• Applying insulation layer for un-
appropriate period “short Period” (heat
shock)
Reduce the temperature of
the core, Cool Down the core
by use of cooing pipe
Contactor, • “expansive solution”, applied in dam
structures only
Using Suitable Formwork
Type (such as plywood)
Especially for wall
Contactor • Construction Restraints.

Mix Design Concepts for reducing Tmax
Heat of hydration generates from the reaction of cement and water, reactions of
cementitious materials such as Fly ash, GGBFS and silica fume generate heat of
hydration also but with lesser amount compered with the reaction of cement and
water.
Aggregate are inert materials and do not contribute in generating any heat of
hydration
Most admixture do not contribute in generating of heat of hydration, some of them
may affect the rate of reaction but not contribute in heat generation
So……
The concept of mix design for reducing Tmax depends on
using the lowest amount of cementitious materials.

Design Concepts for reducing ∆𝑻
Recuing Tmax helps in reducing ∆𝑻 when applying suitable type of surface insulation.
For Saudi Arabia conditions, mix design usually play a little contribution in reducing
∆𝑻,
So……
The main contribution is coming through the surface insulation

Design Concepts for increasing Tensile Strain Capacity
of Concrete
Use the type of aggregate that produce lower coefficient of thermal expansion such as
Limestone aggregate.
Applying design methods to increase the tensile strength of the concrete at early age
without increasing the cementitious content (such as the use of fiber)

OPC Mixes for Mass Concrete “No Additive to be used”
In general, the estimated temperature rise for OPC is (12.5 – 15 °C/100 kg) based on
the thickness of the structure:
Structure Thickness
(mm)
Estimated temperature rise
(°C/100 kg )
1000 12.5
1500 13.5
2000 14
2500 14.5
3000 14.8

GGBFS Mixes for Mass Concrete
CIRIA C660 Suggests the
following figures for estimating
the temperature rise for GGBFS
mixes in mass concrete
GGBFS Mixes benefits in mass concrete:
 Reduce Tmax.
 Lower Rate of Heat Generation.
 Delay the setting time of concrete.

Fly Ash Mixes for Mass Concrete
CIRIA C660 Suggests the
following figure for estimating the
temperature rise for Fly Ash
mixes in mass concrete
Benefits of Fly Ash Mixes:
 Reduce Tmax.
 Lower Rate of Heat Generation.
 Delay the setting time of concrete.

Silica Fume Mixes for Mass Concrete
It is generally recognized that the heat generated by silica fume concrete is
similar to that of OPC at the same Cementitious material content. More
recent measurements have supported this concept.
The cementing efficiency is much higher than that of OPC, and silica fume
may be used to achieve the same strength with a reduced Cementitious material
content hence reducing Tmax

Ground Limestone Mixes for Mass Concrete
In terms of generating heat Ground Limestone Powder may be
assumed to have minor to little effect of the heat of hydration.

Ground Natural Pozzolans Mixes for Mass Concrete
In terms of generating heat Ground Natural Pozzolans may be
assumed to have minor to little effect of the heat of hydration.

Use of Cementitious tolerates specifying higher Tmax
Use of GGBFS and Fly
Ash reduce the negative
effects of high
temperature on the
ultimate strength of
concrete
The relationship between the peak temperature and the strength (relative to the 28-day cube) using OPC
cement , Portland limestone cement (PLC), and combinations of OPC cement with 30 per cent fly ash
cement (P/FA-B) and 50 per cent ggbs (P/B)

Use of Cementitious tolerates specifying higher Tmax
The following guidance is given in BRE IP11/01 (BRE, 2000) in relation to the risk of DEF.
Tmax < 60 °C no risk
Tmax < 70 °C very low risk
Tmax < 80 °C low risk
These above limits apply to Portland cement concretes. BRE IP11/01 states that Fly Ash at
levels of > 20 per cent or GGBFS at levels of > 40 per cent will prevent DEF-induced
expansion in concrete subject to peak temperatures of up to 100 °C.
The risk of DEF may be reduced most effectively by the use of fly ash of ggbs in suitable
quantities which will have the combined effect of both reducing the temperature rise and
increasing the temperature at which DEF will occur.
Use of GGBFS and Fly Ash reduce the negative effects of DEF

Other Factors may be considered in mix design
 Strength Age: convince the customer to specify the strength at 56
days or 90 days instead of 28 days “if possible” to be able to use
lower cementitious materials content.
 W/CM: use the lowest possible W/CM, this allows using the lowest
cement content (Less Tmax) and increase the tensile strength of
concrete (less thermal risk).
 Aggregate: use limestone aggregate “if possible”.
 Placing Temperature: use the lowest placing temperature “if
possible”.
 Fiber: use fiber if possible to increase the tensile strength of
concrete.

Reducing (∆𝑻 ) by Applying Insulation Layer on raft
foundation surface.

Reducing (∆𝑻 ) by Selecting the right Formwork Type in
Thick Walls

The Risk of the use of Excessive insulation
Using excessive or unnecessary insulation to minimize temperature differentials may
lead to an increase in the mean temperature of the structure and hence the risk of
thermal cracks. It may lead to thermal shock in case of removing the insulation at
inappropriate time.

Heat Shock
Removing insulation layers in raft foundation or formwork in thick walls too early
increases the deferential temperature rapidly and my lead to thermal cracking. This is
called “Heat Shock”

Important Definitions
 Adiabatic condition: adiabatic environment is the environment perfectly thermally
insulated.
 Heat is Energy, Heat Quantity is measured by (Kj/Kg), it is Quantity dependent
variable “depends on the quantity of .
 Temperature: does not depend on the quantity of the substance measured by °C.
 Heat Flow: Heat flows in the direction of decreasing temperature. (for concrete,
generally from the interior to exterior, since the interior tend to be hotter.
 Adding Heat to a substance increases its temperature.

IQ-Drum
IQ-Drum is a semi-Adiabatic Calorimeter, a plastic cylinder 150×300mm filled by
concrete then place in its place in IQ-drum then connected to thermo-sensor attached
to the IQ-drum by a thermocouple.
IQ-Drum Measurements:
IQ-drum measures: (every 15 minutes)
• sample temperature (measured in °C) and
• the rate of heat loss from the calorimeter (measured in millivolt) .
IQ-Drum Results:
IQ-drum compute
• The hydration rate and
• heat amounts by compensating for heat loss to reach to the adiabatic conditions.

IQ-Drum Test Start-up
 Define Mix proportion in Quadrel iService.
 Define Trial Mix “sample log”.
 Define IQ-drum Test.
 Enter the size of cylinder mold
 Enter the weigh of concrete inside cylinder mold.
 Click “Start” button.

Heat Profile Developed by IQ-drum Measurement
Two Heat profiles will be developed by the IQ-drum measurements:
 AHS: Adiabatic Heat Signature = Adiabatic heat of hydration (Kj/Kg) and its rate (Kj/kg.hr)
versus the maturity curing age (Maturity Hours).
 ATR = Adiabatic Temperature Rise = Adiabatic temperature (°C) and its rate (°C/hr)versus
the maturity curing age.
 Maturity = Equivalent curing age at 20 °C compute by the Arrhenius rate equation.

AHS – Adiabatic Hydration Heat and its Rate

ATR– Adiabatic Temperature Rise and its Rate

Simulation of Mass Concrete Structure Element
To simulate the heat of hydration in mass concrete structure elements usually we need
the following:
 Heat of Hydration profile “heat of hydration Signature”: which we get it by IQ-drum test
measurements.
 Structure thickness.
 Concrete Placing Temperature.
 Ambient temperature profile during simulation period.
 Soil Information: the structure under the element will be casted.
 Work Plan. Which means surface curing plan in raft foundation and thick slab, or formwork
type in thick walls and columns.

Simulation of Mass Concrete Structure Element

What is the difference between Quadrel Simulation and
some other simulation programmers.
 There are a lot of cheap simulation programmers available and do not require a specific
calorimeter device such IQ-drum, they are developed based on default heat of hydration
profiles, for instance the module developed by CIRIA 660 depends on adiabatic curves
derived from extensive testing at the University of Dundee.
 The degree of errors in simulation may be significant if the materials actually used differ from
those used by the University of Dundee.
 Quadrel simulation depends on the actual heat profile for the mix will be actually in the
project, which built by IQ-drum test measurements.
 Quadrel Simulation gives more accurate results because it depends on the mix proportion
and materials will be used in the actual pouring.

Simulation Chart – Max, Min and ∆𝑇 Curves
OPC cement only.
Cement Content = 500 Kg.
Structure Thickness = 3 m.
Placing Temp. = 30 °C.
Simulation Period = 7 days.
Water Curing (7 days)

Simulation Charts at specific Depth
Max Temperatures Curve
Temperatures Curve
at 2500 mm depthMin Temperatures Curve
Differential Temperatures Curve
OPC cement only.
Structure Thickness = 3 m.

Effect of Structure Thickness
OPC cement only.
500
mm
75
17
1000
mm
88
27
2000
mm
97
33
3000
mm
99.4
41

Important Points related to Thickness Effect
 Thickness increases  Tmax increases and ∆𝑇 increases .
 Thickness increases  Longer Time of Tmax to achieve.
 Thickness increases  Longer time to Tmax to drop.
 Thickness increases  Longer time to ∆𝑇𝐦𝐚𝐱 to achieve.
 In pervious slide for 500 and 1000 mm thickness ∆𝑇𝐦𝐚𝐱 achieved during heating period
while in 2000 and 3000 mm ∆𝑇𝐦𝐚𝐱 achieved during cooling period.
 At 7 days (end of water curing plan)
 for 500 mm: Tmax = 40.4 °C , ∆𝑇𝐦𝐚𝐱 = 2.4 °C
 for 3000 mm: Tmax = 92.8 °C , ∆𝑇𝐦𝐚𝐱 = 40 °C

Important Points related to Thickness Effect
 after 7 days (concrete is uninsulated, water curing plan stopped)
 for 500 mm: Tmax = increased (↑1°C), ∆𝑇𝐦𝐚𝐱 = 5.4 °C (↑ 3°C),
 for 1000 mm: Tmax = Not Increased , ∆𝑇𝐦𝐚𝐱 = 15.9°C (↑4.6°C).
 for 2000 mm: Tmax = Not Increased, ∆𝑇𝐦𝐚𝐱 = 35.6°C (↑7.5°C),
 for 3000 mm: Tmax = 92.8°C (↑1°C), ∆𝑇𝐦𝐚𝐱 = 48.4 °C (↑8.4°C),

Effect of Placing Temperature
Tplacing = 30 C, Tmax = 99.3 C, ∆𝑇𝐦𝐚𝐱 = 40.7 C
Tplacing = 25 C, Tmax = 94.4 C, ∆𝑇𝐦𝐚𝐱 = 38 C
Tplacing = 20 C, Tmax = 90.4 C, ∆𝑇𝐦𝐚𝐱 = 35 C.
Conclusions:
• There is a liner relationship between Tplacing and
Tmax,
• 1 C increment in Tplacing = 1 C increment in Tmax
• Tplacing affects on ∆𝑇𝐦𝐚𝐱 also, Tplacing increases
∆𝑇𝐦𝐚𝐱 increases
30 C
25 C
20 C
Tplacing = 30 C

Effect of Ambient Temp. (Typical Values in Saudi Arabia)
Dammam Riyadh
Jeddah

Effect of Ambient Temperature – 3 m foundation
Tambient = (45 – 30) : Tmax = 99.4 C, ∆Tmax = 40.7 C
Tambient = (35 – 20) : Tmax = 98.7, ∆Tmax = 46.9 C
Conclusions:
• Change in ambient temperature has significant
effect on ∆Tmax
• Change in ambient temperature has minor effect on
Tmax (for thick sections).
• Change in ambient temperature has an effect on
Tmax (for then sections).
45 - 30 C
35 - 20 C
25 - 10 C
Tplacing = 30 C

Effect of Ambient Temperature – 1 m foundation
Tambient = (45 – 30) : Tmax = 99.4 C, ∆Tmax = 40.7 C
Conclusions:
• Change in ambient temperature has significant
effect on ∆Tmax
• Change in ambient temperature has minor effect on
Tmax (for thick sections).
• Change in ambient temperature has an effect on
Tmax (for then sections).
45 - 30 C
35 - 20 C
25 - 10 C
Tplacing = 30 C

Effect of Pouring Time
07:00 : Tmax = 99.6 °C, ∆Tmax = 40.7 C
15:00 : Tmax = 99.4 °C , ∆Tmax = 40.7 C
23:00 : Tmax = 99.2 °C, ∆Tmax = 40.7 C
Conclusions:
• Pouring time has no effect on ∆Tmax
• Pouring time has a negligible effect on Tmax for
same placing temperature
Important:
• Pouring time has more effect on placing
temperature which has direct effect on Tmax
07:00 23:00
15:00
Tplacing = 30 C

Effect of Soil information –
Concrete with various temperatures- 3 m foundation
Tsoil = Tplacing = 30 C : Tmax = 99.4 °C, ∆Tmax = 40.7
C
Tsoil = 45 C : Tmax = 99.9 °C , ∆Tmax = 41.4 C
Tsoil = 15 : Tmax = 99 °C, ∆Tmax = 39.7 C
Conclusions: for thick Structure
• Tsoil has minor effect on ∆Tmax
• Tsoil has minor effect on Tmax.
Tplacing = 30 C
Tsoil = 45 C
Tsoil = 30C = Tplacing Tsoil =15 C

Effect of Soil information –
Concrete with various temperatures- 1 m foundation
Tsoil = Tplacing = 30 C : Tmax = 87.6 °C, ∆Tmax = 27.2
C
Tsoil = 45 C : Tmax = 90.9 °C , ∆Tmax = 23.6 C
Tsoil = 15 : Tmax = 83.7 °C, ∆Tmax = 43 C “Impractical
case as it is very rare that Tplacing 30 and Tsoil 15”
Conclusions: in thin structure
• Tsoil has significant effect on both Tmax and
∆Tmax
Tplacing = 30 C
Tsoil =15 CTsoil = 30C = Tplacing
Tsoil = 45 C

What if Tsoil = 45C, Tambient = 45 – 30 and Tplacing =
20C, 3 m foundation
Surface
SoilTmax
∆T
Tmin

What if Tsoil = 45C, Tambient = 45 – 30 and Tplacing =
20C, 3 m foundation
Surface
Soil
Tmax
∆T
Tmin

Effect of Work Plan – 3m Raft Foundation
Work Plan: wind speed= 3 m/s
Permanently Uninsulated Surface:
Tmax = 99.2 C, ∆Tmax = 54.6 C
Work Plan: wind speed = 3 m/s
Uninsulated for 16 hours.
2 layer of plastic sheet for 168 hours.
Tmax = 99.2 C, ∆Tmax = 51.5 C
Tplacing = 30 C

1.8 cm Plywood for 168 hours.
Tmax = 99.9 C, ∆Tmax = 33 C
2 cm Water Curing for 168 hours.
Tmax = 99.5 C, ∆Tmax = 40.6 C
Tplacing = 30 C

2 cm StyroFoam for 168 hours.
Tmax = 100 C, ∆Tmax = 33.4 C
2 cm EthaFoam for 168 hours.
Tmax = 100 C, ∆Tmax = 33.5 C
Tplacing = 30 C

NO Work Plan: Structure perfectly insulated
Tmax = 101.3 C, this is the maximum Tmax can be reached
∆Tmax = 33.4 C, this is the minimum ∆Tmax can be reached
PERFECTLY
INSULATED
Heat Loss
will be
through Soil
Only
“No Loss
from the
surface”
Tplacing = 30 C

Tplacing = 30 C
Permanently Uninsulated Surface:
Tmax = 88.4 C, ∆Tmax = 34.6 C
2 cm water curing for 168 hours.
Tmax = 88.3 C, ∆Tmax = 27 C

Effect of Work Plan – 1m Wall
1.8 cm Plywood Formwork.
Striking Time = 168 hours
Tmax = 93 C, ∆Tmax = 14.4 C
0.4 cm Steel Formwork.
Tmax = 89.8 C, ∆Tmax = 34.8 C
Tplacing = 30 C

Heat Shock: removing Insulation after 3 days – 3m
Foundation
Tplacing = 30 C
Tmax = 99.9 C, ∆Tmax = 33 C
Tmax = 99.9 C, ∆Tmax = 54 C

Heat Shock: Formwork Striking after 3 days – 1m Wall
Tplacing = 30 C
Tmax = 93 C, ∆Tmax = 14.4 C
Tmax = 93 C, ∆Tmax = 30 C

Extensive Insulation to achieve conservative ∆T ≤ 20 C
Insulation
Applied
∆T
(Tplacing
30 C)
∆T
(Tplacing
20 C)
∆T
(Tplacing
20 C)
∆T
(Tplacing
20 C)
Remarks
During 7 days of
insulation
Removing
Insulation
after
7days
Removing
Insulation
after
3days
No
insulation
applied
40 36
2 pieces of
Plastic
Sheet
38 30 29 32
2cm Water 30 24 28 32
1.8 cm
Plywood
23 19 29 32 Surface condition let
the structure to be
close to Perfectly
insulated condition
“Main heat lost is
through soil”
2cm
Styrofoam
23 19 29 32
Perfectly
insulated
23 19
60% GGBFS. 5%MS, 35%OPC
Total CM = 490 Kg
Structure = Foundation
Thickness = 3 m
Work Plan for 7 days
Aggregate Type: Limestone
Project Specification:
Tmax = 75 C
∆T ≤ 20 C
CIRIA C660: ∆T ≤ 35 C
Tmax = 82 at Tplacing 30.
Tmax = 72 at Tplacing 20 C.

Effect of Wind Speed. (Typical Wind Speed in Saudi Arabia )
Dammam Riyadh
Jeddah

Effect of Wind Speed. (Raft Foundation)
Tplacing = 30 C
Work Plan:
Uninsulated
Surface
OPC mix
CM = 500 kg.
Ambient (45 – 30)
Wind Speed ∆T
(3m)
∆T
(2m)
∆T
(1m)
Tmax
(3m)
Tmax
(2m)
Tmax
(1m)
3 m/s (11 km/h) 55 48.7 34.7 100 96.5 86.7
6 m/s (22 km/h) 59.3 53.8 40 100 96.5 86.3
9 m/s (33 km/h) 61.5 56.2 42.7 100 96.5 86
12 m/s (44 km/h) 61.8 57.8 44 100 96.5 85.6
15 m/s (55 km/h) 63.5 59.1 45 100 96.5 85.6
(0 m/s) 39 31.5 27.5 100 96.5 88.5

Effect of Wind Speed. (Thick Wall)
Tplacing = 30 C
OPC mix
CM = 500 kg.
Ambient (45 – 30)Wind Speed ∆T
(2m)
∆T
(1m)
∆T
(0.5m)
Tmax
(2m)
Tmax
(1m)
Tmax
(0.5m)
3 m/s (11 km/h) 23.6 14.5 7.4 98.4 93 86
6 m/s (22 km/h) 24.8 15.3 7.6 98.4 93 85.5
9 m/s (33 km/h) 25.2 15.4 7.8 98.4 92.9 85.3
12 m/s (44 km/h) 25.4 15.6 8 98.4 92.9 85.1
15 m/s (55 km/h) 25.4 15.6 8 98.4 92.9 85.1
(0 m/s) 19.5 11.3 5 98.5 93.8 87.6
Plywood
Formwork
Wind Speed ∆T
(2m)
∆T
(1m)
∆T
(0.5m)
Tmax
(2m)
Tmax
(1m)
Tmax
(0.5m)
3 m/s (11 km/h) 49 34.8 25.1 97.6 89.8 79.2
6 m/s (22 km/h) 54.6 39 31 97.4 89.2 79.2
9 m/s (33 km/h) 57.4 41.5 34.2 97.4 89 79
12 m/s (44 km/h) 59.2 43.6 36.1 97.1 88.9 78.7
15 m/s (55 km/h) 60 44.6 37.2 97.1 88.5 78.7
(0 m/s) 33.1 21.6 11.8 97.8 91.5 82
Steel
Formwork

Effect of Fly Ash
Wind Speed Tmax ∆T Mi Mp MxRate Q28 Q90
Control 89 32 12.3 17.2 15.2 300 305
20%FA 83 30 13.4 19 11.5 266 270
30% FA 78 28 16.3 23.1 9.2 245 262
40% FA 74 25 21.5 30.5 7.7 220 229
50% FA 70 23 32.4 39.5 6 205 217

Effect of GGBFS
Wind Speed Tmax ∆T Mi Mp MxRate Q28 Q90
Control 89 32 12.3 17.2 17.2 300 305
40%GGBFS 85.5 32.8 16.1 20.6 10.8 279 285
50%GGBFS 80 29.3 10.4 14.8 8.7 283 293
60%GGBFS 77 27 7.5 14.6 7.5 234 237
70%GGBFS 75 26 12.6 17.9 4.8 242 251

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