The Study on Early-Age Expansion and Shrinkage Model of Massive Self-Compacting Concrete Pumped in Steel Tube Column

Table 6

The parameter values of time-development function for the early-age shrinkage and expansion.

Type of steel tube column	Expansion and shrinkage direction	Time-development function β(t) = [(A0 − 1)/(1 + (t/α)^β)] + 1(0 ≤ t)				Curve mark
		A 0	α	β	Days of maximum expansion strains t0
SYZ-1	Vertical	−0.15	5.0	2.0	1.8	Model in Figure 9(a)
	Horizontal	−0.35	5.0	2.0	2.0	Model in Figure 9(a)
SYZ-2	Vertical	−0.06	4.5	1.5	0.4	Model in Figure 9(b)
	Horizontal	−0.30	4.5	1.5	1.2	Model in Figure 9(b)

It should be explained here that, before the day t₀ of the maximum expansion strains that can be achieved, the parameter A₀ is a variable; and then it is the constant value. According to the time 0 − t₀ in Table 6, the parameter A₀ is interpolated linearly according to 0 − A₀.