Degradation Behaviour of Deteriorated RC Beams Strengthened with CFRP under the Compound Effects of Acid-Salt Mist and Carbon Dioxide

Table 4

Basic parameters of deteriorated RC beams.

No.	Time (months)	fcu (MPa)	x(t) (mm)	η (%)	Fu (kN)	Δy (mm)	Δu (mm)	μΔ	Failure mode
L0	0	35.2	0	0	80	3.05	10.21	3.35	CC
L1	0	35.0	0	0	78	2.98	10.39	3.49	CC
L2	18 + 15	25.9	24.5	11.64	89	3.11	11.73	3.77	PS
L3	18 + 15	24.3	24.9	14.33	70	3.80	8.66	2.28	PS
L4	21 + 15	23.8	25.4	15.46	75	4.93	9.77	1.98	PS
L5	21 + 15	17.4	28.8	14.35	68	3.14	8.38	2.67	PS
L6	21 + 18	15.8	31.4	19.11	65	4.42	13.35	3.02	PS
L7	24 + 15	20.4	30.4	19.36	84	4.74	11.46	2.42	PS
L8	21 + 21	25.84	—	23.26	43	4.15	9.82	2.37	CC
L9	24 + 18	22.09	—	19.30	55	4.47	9.96	2.23	PS
L10	27 + 15	22.26	—	21.17	85	3.98	11.43	2.87	PS
L11	30 + 15	20.48	—	22.75	90	4.48	11.03	2.46	PS

Note: (a) time “18 + 15” means that t_1i = 18, and t_2i = 15, and the same as follows. (b) CC = crushing of concrete in the compression zone; PS = peel off of CFRP. (c) As the concrete cover of the beam L10 and L11 were lost, the grouting material was used to re-cast the protective layer firstly, and then, the beams were strengthened with CFRP like the others.