Lightweight Concrete for High Strength - Expanded Shale & Clay

where
ε
sh ∞
⎧ 510 µε for steam
- cured concrete
= ⎨
⎩560
µε for moist - cured concrete
; ultimate shrinkage strain
until ⎧ ⎡
⎤⎫
day n
⎪ ⎢ 4000
⎥⎪
t = ∑ ∆ti
⋅ exp⎨−
⎢
−13.
65⎥⎬
; maturity of concrete (days) after “n” days
⎪
T ( ∆t
)
⎢273
+
i
⎥⎪
⎩ ⎣
T 0 ⎦⎭
until
beginning
drying
⎧ ⎡
⎤⎫
⎪ ⎢ 4000
⎥⎪
t0
= ∑ ∆ti
⋅ exp⎨−
⎢
−13.
65⎥⎬
; maturity of concrete at the beginning of drying
⎪
T ( ∆t
)
⎢273
+
i
⎥⎪
⎩ ⎣
T0
⎦⎭
(days)
∆t i : period of time (days) at temperature T(∆t i ) ( o o
o
C) ( C = 0.556×
F −17.
778)
T 0 : 1 o C
k vs
⎡
⎢
⎢
26 ⋅ exp 0.36
=
⎢
⎢
⎢ 45
⎣
( t − t )
0
{ ⋅V
} + ( t − t0
)
S
( t − t0
)
+ ( t − t )
0
⎤
⎥ ⎡
⎤
⎥
1064 − 0.94 ⋅V
⋅ ⎢
S ⎥
⎥
; size factor
⎢ 923 ⎥
⎥ ⎣
⎦
⎥⎦
k H
⎧2.00
−1.43⋅
h
= ⎨
⎩4.29
− 4.29 ⋅ h
for h < 0.80
; ambient relative humidity factor
for h ≥ 0.80
h: relative humidity in decimals
⎧ 4.2 ⎫
kt
= 0.67 ⋅ exp⎨
⎬; factor for maturity at the beginning of drying
0
⎩9.45
+ to
⎭
f: 23 (days)
B-11