Tests and Analysis on Thermal Expansion Behaviour of Steel Strand used in Prestressed Concrete Structure under Low Temperatures

International Journal of Concrete Structures and Materials

Table 2 Transit linear expansion coefficients for steel strands under different low temperature and prestressing stress.

T (°C)	f_t/f_tk ratio	α_t in Group A (× 10⁻⁶/°C)					T (°C)	f_t/f_tk ratio	α_t in Group B (× 10⁻⁶/°C)
T (°C)	f_t/f_tk ratio	A1	A2	A3	Mean	C.O.V.	T (°C)	f_t/f_tk ratio	B1	B2	B3	Mean	C.O.V.
0	0.00	11.5	12.3	11.5	11.8	0.04	0	0.40	13.5	13.7	13.7	13.6	0.01
− 20	0.00	11.0	11.6	11.0	11.2	0.03	− 20	0.40	12.9	13.1	13.0	13.0	0.01
− 40	0.00	10.4	10.9	10.4	10.6	0.03	− 40	0.40	12.3	12.5	12.4	12.4	0.01
− 60	0.00	9.8	10.2	9.8	10.0	0.02	− 60	0.40	11.7	11.8	11.8	11.8	0.01
− 80	0.00	9.3	9.6	9.3	9.4	0.02	− 80	0.40	11.1	11.2	11.1	11.1	0.00
− 100	0.00	8.7	8.9	8.7	8.8	0.01	− 100	0.40	10.5	10.5	10.5	10.5	0.00
− 120	0.00	8.2	8.2	8.2	8.2	0.00	− 120	0.40	9.9	9.9	9.8	9.9	0.00
− 140	0.00	7.6	7.5	7.6	7.6	0.01	− 140	0.40	9.3	9.3	9.2	9.2	0.00
− 165	0.00	6.9	6.7	6.9	6.8	0.02	− 165	0.40	8.5	8.5	8.4	8.5	0.01

T (°C)	f_t/f_tk ratio	α_t in Group C (× 10⁻⁶/°C)					T (°C)	f_t/f_tk ratio	α_t in Group D (× 10⁻⁶/°C)
T (°C)	f_t/f_tk ratio	C1	C2	C3	Mean	C.O.V.	T (°C)	f_t/f_tk ratio	D1	D2	D3	Mean	C.O.V.
0	0.50	14.1	14.3	13.8	14.1	0.02	0	0.65	14.8	14.2	14.1	14.4	0.03
− 20	0.50	13.4	13.6	13.2	13.4	0.02	− 20	0.65	14.1	13.6	13.5	13.7	0.02
− 40	0.50	12.7	12.9	12.6	12.7	0.01	− 40	0.65	13.4	12.9	12.9	13.1	0.02
− 60	0.50	12.0	12.2	12.0	12.0	0.01	− 60	0.65	12.8	12.3	12.3	12.4	0.02
− 80	0.50	11.3	11.4	11.4	11.4	0.01	− 80	0.65	12.1	11.6	11.7	11.8	0.02
− 100	0.50	10.5	10.7	10.8	10.7	0.01	− 100	0.65	11.4	11.0	11.1	11.2	0.02
− 120	0.50	9.8	10.0	10.2	10.0	0.02	− 120	0.65	10.7	10.4	10.5	10.5	0.02
− 140	0.50	9.1	9.3	9.6	9.3	0.03	− 140	0.65	10.0	9.7	9.9	9.9	0.02
− 165	0.50	8.2	8.4	8.8	8.5	0.04	− 165	0.65	9.2	8.9	9.2	9.1	0.02

T (°C)	f_t/f_tk ratio	α_t in Group E (× 10⁻⁶/°C)					T (°C)	f_t/f_tk ratio	α_t in Group E (× 10⁻⁶/°C)
T (°C)	f_t/f_tk ratio	E1	E2	E3	Mean	C.O.V.	T (°C)	f_t/f_tk ratio	E1	E2	E3	Mean	C.O.V.
0	0.75	14.8	14.7	15.2	14.9	0.02	− 100	0.75	11.6	11.5	11.4	11.5	0.01
− 20	0.75	14.2	14.1	14.4	14.2	0.01	− 120	0.75	11.0	10.9	10.6	10.8	0.02
− 40	0.75	13.6	13.4	13.7	13.6	0.01	− 140	0.75	10.4	10.2	9.9	10.2	0.02
− 60	0.75	12.9	12.8	12.9	12.9	0.01	− 165	0.75	9.6	9.4	8.9	9.3	0.04
− 80	0.75	12.3	12.1	12.2	12.2	0.01