# Bond Properties Between Bimetallic Steel Bar and Polyoxymethylene Fiber-Reinforced Seawater Sea–Sand Concrete

## TL;DR

This study explores how adding POM fibers to seawater sea-sand concrete improves its bond strength with bimetallic steel bars, offering a sustainable construction solution.

## Contribution

The paper introduces a predictive model for bond stress-slip behavior in POM fiber-reinforced seawater sea-sand concrete with bimetallic steel bars.

## Key findings

- The optimal POM fiber volume fraction is 0.6%, improving compressive and tensile strength by 17.7% and 20.3%, respectively.
- Bond strength increases with relative cover thickness and stabilizes with higher POM fiber content.
- A bond stress-slip model was developed to support numerical simulations and structural design.

## Abstract

With the development of infrastructure construction, seawater sea–sand concrete (SWSSC) is expected to solve the shortage of freshwater and river sand. Polyoxymethylene (POM) fiber, owing to its excellent corrosion resistance, provides a novel approach to enhancing the bond performance of SWSSC. This study systematic study of the bond properties of bimetallic steel bars (BSBs) in POM fiber-reinforced SWSSC and develops a predictive model. Mechanical property tests of SWSSC and pull-out tests of BSB and SWSSC were conducted with various POM fiber contents. The results showed that the optimal volume fraction of POM fibers was 0.6%. At this fraction, the compressive strength and splitting tensile strength of SWSSC were improved by 17.7% and 20.3%, respectively, compared with the group without fibers. All pull-out specimens experienced splitting failure. The bond strength increased monotonically with the increase in relative cover thickness and exhibited a trend of first increasing and then stabilizing with rising POM fiber volume fraction. In addition, a bond stress–slip prediction model between BSBs and POM fiber-reinforced SWSSC was established based on the test results, which can provide theoretical support for the numerical simulation and design of BSB-SWSSC structures.