Load-Bearing Capacity of GFRP Bar Sea Sand Concrete Deep Flexural Members in Chloride Environment

doi:10.16552/j.cnki.issn1001-1625.2025.0800

Abstract

Abstract:

In coastal and marine engineering， using sea sand to replace river sand can reduce the costs associated with cross-regional transportation of river sand and help protect terrestrial ecosystems. Coupled with the use of glass fiber reinforced polymer （GFRP） bars instead of steel reinforcement， it effectively resolves the issue of chloride ion corrosion in sea sand.For the common bent caps and other deep flexural members in offshore bridges， 30 GFRP bar-sea sand concrete deep flexural members were fabricated， and their load-bearing performance was tested after immersion in a chloride environment for different durations， including failure modes， deflection， cracking， and ultimate load capacity. The results show that chloride salt immersion changes the failure mode of GFRP bar-sea sand concrete deep flexural members from concrete crushing to shear failure. As the immersion time increases， the cracking load of the members increases， the ultimate load capacity of the members decrease， the cracks number of the members gradually reduces， and the maximum deflection value of the members increase. Based on the test results， the existing code formula for calculating the load-bearing capacity of reinforced concrete deep flexural members is modified by introducing the GFRP bar reduction factor index. The modified formula can well predict the ultimate load capacity of GFRP bar-sea sand concrete deep flexural members after immersion in a chloride environment.

Key words: chloride environment, GFRP, sea sand concrete, deep flexural member, load-bearing performance, predicted model

CLC Number:

TQ327.1

JIN Qingping, YANG Zhenyuan, LIANG Yingqiang, LIU Yundie, SONG Shie. Load-Bearing Capacity of GFRP Bar Sea Sand Concrete Deep Flexural Members in Chloride Environment[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(1): 81-91.

Figures/Tables 16

Table 1 Mix proportion of sea sand concrete

Design level	Water-cement ratio	Cement/（kg·m^-3）	Water/（kg·m^-3）	Sand/（kg·m^-3）	Gravel/（kg·m^-3）
C40	0.4	537.5	215	494.25	1 153.25

Table 2 Results of mechanical properties test of sea sand concrete

Design strength of concrete	Compressive strength/MPa			Flexural strength/MPa
C40	32.8	41.8	40.6	2.73	3.08	3.21

Fig.1 Macroscopic morphology of GFRP bars

Fig.2 GFRP bars tensile test apparatus

Table 3 Mechanical properties parameters of GFRP bar

Material	Diameter/mm	Tensile strength/MPa	Elastic modulus/GPa
GFRP bar	6	1 042.93	59.7

Fig.3 GFRP bar-sea sand concrete deep flexural member

Fig.4 Preparation for test loading

Fig.5 Test setup

Fig.6 Typical failure mode of deep flexural members

Fig.7 Load-strain curves of GFRP bars at same soaking time

Fig.8 Load-deflection curves of member at same soaking time

Fig.9 Deflection curves at midspan when member cracks at same soaking time

Fig.10 Load-crack width curves at same soaking time

Fig.11 Component crack development

Fig.12 Ultimate load capacity curves of member

Fig.13 Predicted value and measured value of

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