New Technologies for concrete temperature rise · PDF fileNew Technologies for concrete temperature rise inhibition ... Basic principle of concrete temperature rise ... and lowering

New Technologies for concrete temperature

rise inhibition

-concrete temperature rise inhibitor (TRI)-

Qian Tian

State key Laboratory of High Performance Civil Engineering Materials

Jiangsu Sobute New Materials Co.,Ltd

Nanjing, China

江苏博特新材料有限公司 Jiangsu Bote New Materails Co., Ltd. www.cnjsjk.cn 2

OUTLINES

Background

Basic Principle

Experimental results

Engineering applications

Conclusions


Tem

per

atu

re r

ise

age

center

surface Tem

per

ature

dif

fere

nce

Tem

per

ature

dro

p

Casting temperature

Temperature evolution of a

concrete structures

Thermal cracking is a major problem for concrete structures

Internal restraint due to temperature difference;

External restraint due to temperature drop;

Accelerate the intrusion of external harmful ions.

Tem

per

ature

rise

BACKGROUND

Appear when demould；

Parallel and even spaced；

Throughout and leads leakage


BACKGROUND

The increase of cement fineness and early strength leads to a

much faster heat generation rate, which substantially increase the

temperature rise and thermal crack risk.

Effect of cement fineness on the

rate of heat generation(ACI 207) Evolution of cement in USA(Burrows)

The evolution of cement promotes the danger of thermal cracking


BACKGROUND

Factors

influncing

thermal

cracking

design

material Constru

-ction

Manage

-ment

Super

-vision

Could we countermeasure in terms of the materials itself?

There are many measures to control thermal cracking, mostly from

the construction side consuming time and effort.

Mostly used mitigation methods in

the construction site


Basic principle of concrete temperature rise inhibitor(TRI)

Retard heating rate at stage III, distributing the heat release over time

and lowering maximum temperature in concrete structure;

Lengthening the temperature rise and the subsequent temperature

drop history, enhancing the creep relaxation.

Calcium chelation

Minimize the early age heat discharge;

Provide more time for structure cooling;

Keep the same ultimate heat releasing.

Water Reservoir

inlet

outlet

Basic principle


Isothermal calorimeter

Adiabatic temperature rise

Testing methods of hydration heating process

Semi-adiabatic temperature rise

Isothermal Calorimeter provides the best

radiation condition, indicates the four-stages

hydration stages;

Adiabatic Temperature Rise provides the worst

radiation condition,

The real concrete structures are generally

between these two extreme conditions, i.e.Semi-

adiabatic conditions.

Capillary pressure sensor

Temperature sensor

Thermal insulation layer

Concrete

Experiamental results


temperature histories of concrete

(Monitoring results)

SR: extend the induction period, slightly affect hydration rate

during accelerating stage and temperature rise.

TRI: lower maximum heat releasing rate, significantly reduce the

temperature rise

Difference between setting retarder(SR) and TRI

hydration evolution curve

(TAM Air)

0 50 100 150 2000

1

2

3

Sucrose

TRI

REF

Hea

t fl

ow

(m

W/g

)

Time (Hours)

0 1 2 3 4 5 6 720

25

30

35

40

45

Sucrose

REF

Tem

pera

ture

(C

)

Time (Hours)

TRI



Reduces the peak value of heat flow by 76%;

Significantly reduce the hydration evolution

No influence on the ultimate hydration heat.

Effect of TRI on cement hydration under isothermal condition

Time TRI

1d 9%

2d 30%

3d 43%

5d 63%

7d 80%

12d 98%

Percentage of heat of the

cement paste with TRI

compared to the reference

76%

0 50 100 150 2000

1

2

3

TRI

REF

Hea

t fl

ow

(m

W/g

)

Time (Hours)

0 50 100 150 200 250 300 350 4000

50

100

150

200

250

300

350

400

Hea

t (J

/g)

Time (Hours)

REF

TRI



Percentage of temperature rise of

the concrete with TR compared to

the reference (%)

Retard the early-age temperature rise of concrete effectively;

Catch up with the reference concrete at a latter age(7-10d);

No influence on the ultimate temperature rise.

Effect of TRI on hydration under Adiabatic condition

Time TRI

1d 15%

2d 52%

3d 65%

5d 85%

7d 95% 0 2 4 6 8

0

10

20

30

40

50

REF

ad

iab

ati

c t

em

pera

ture r

ise (C

)

Time (Days)

TRI

Cement: 250kg/m3, fly ash:125, w/b=0.42



0 50 100 15020

30

40

50

60

Tem

pera

ture (C

)

Time (Hours)

0 50 10020

25

30

35

40

45

50

Tem

pera

ture (C

)

Time (Hours)

Simulation results showed that addition of TRI decreases the

temperature rise by 4-15℃ for C35 sidewall concrete with thickness

range from 0.3 to 2m.

Effect of TRI on temperature rise of concrete under Semi-adiabatic condition

（simulation）

500mm 1200mm

8.7℃ 6.4℃

0

10

20

30

40

50

60

70 TRI

REF

21.81.51.210.80.5

Ma

xim

um

tem

pera

ture (

℃)

Thickness (m)

0.3



0 1 2 3 4 5 630

40

50

60

70

Ambient temperature

REF

Tem

pera

ture (C

)

Time (Days)

TRI

0 2 4 6 820

30

40

50

TRI

Tem

pera

ture (C

)

Time (Days)

REF

Ambient temperature


6.7℃ 10℃

placing temperature:40℃ placing temperature:25℃

Effect of TRI on temperature rise of concrete under Semi-adiabatic condition

（ measured ）



0 5 10 15 20 25 30

20

30

40

50

60

70

80 2.3℃

8.0℃

Tem

per

atu

re (

℃)

Time (Days)

REF TRI REF+Cooling pipe TRI+Cooling pipe

5.6℃

Cooling pipes

With cooling pipes, decrease the maximum temperature rise (MTR) of

concrete by 5.6oC (12.4% of MTR)

Effect of TRI on mass concrete with cooling pipe



Effect of TRI on strength of concrete

Rebound strength

(placed outdoor) Compressive strength

(curing under RH≥95%)


Rebound strength

(placed outdoor) Compressive strength

(curing under RH≥95%)

20

30

40

50

120

Reb

ou

nd

str

ength

(M

Pa)

Time (Days)

REF

TRI

60



Effect of TRI on C3S and Ca(OH)2 contents during cement hydration

0 5 10 15 20 25 30

0

10

20

30

40

50

60 REF

TRI

C3

S (

%)

Time (Days)0 5 10 15 20 25 30

0

2

4

6

8

10

12

14

16

18

20

REF

TRI

Ca(O

H) 2

(%

)

Time（Days）

Lower the hydration of C3S Inhibit the formation of Ca(OH)2



Integration of the expansive agent & TR(HME)

slump

/mm

Air

/%

Initial

setting/h

:min

Final

setting/

h:min

C30 reference 190 5.5 10:48 13:36

HME 225 5.4 12:07 15:01

C50 reference 197 3.8 10:49 14:01

HME 220 3.3 12:30 14:52

C60 reference 247 2.0 11:10 13:42

HME 255 2.0 15:02 17:00

The addition of TR benefits CaO expansion, produces ‘1＋1>2’ effect;

The composite technology effectively mitigates early-age shrinkage cracking;

Little influence on the workability of concrete.

Effect of HME on the workability of concrete

Effect of TR on the expansion effect of EA



Central temperature histories of

sidewall (Monitoring results)

Sidewall concrete (C30, 0.5m thick)

Sewage treatment plant in Suzhou

Temperature rise was controlled within 21℃ for side wall with successfully

casting length being 45 meters, and no visible penetrating cracks were found.

Cement: 310kg/m3,

fly ash:50kg/m3, w/b=0.49

Demould time

0 1 2 3 4 5 6 7 8

15

20

25

30

35

40

45

Air temperatureT

emp

era

ture

(℃

)

Time (Days)

43.4℃

Engineering Aplications



By addition of TRI no visible cracks were found in section 15# ,

while 11 cracks in section 16# (reference, without TRI)

Cement: 265kg/m3,


Placing temperature: 32℃

Temperature rise: 25.5℃



Demould time

0 2 4 6 8 1020

30

40

50

60

Tem

pera

ture (C

)

Time (Days)

Engineering Aplications Changzhou Subway



By addition of TRI no visible cracks were found in the sidewall

(0.7m thick x 21.8m length x 6m height)

Cement: 270kg/m3,




Placing temperature: 26℃

Temperature rise: 20.7℃

Demould time

0 2 4 6 8 10 12 14

0

10

20

30

40

50

Tem

pera

ture (C

)

Time (Days)

Engineering Aplications Xuzhou Subway


Conclusions TRI can effectively lower cement hydration and heat

release process, and reduce temperature rise of concrete

under certain heat dissipation conditions

TRI leads to lower early strength, especially 3d, 7d, but

have no negative effect on the long-term strength.

TRI inhibits the hydration of C3S and the formation of

Ca(OH)2 in early ages.

Documents

New Technologies for concrete temperature rise · PDF fileNew Technologies for concrete temperature rise inhibition ... Basic principle of concrete temperature rise ... and lowering