The 4th Asian Concrete Federation Symposium on Emerging Technologies for Structural Longevity (ACF2023- ETSL)

137 / 2022-04-28 23:28:46

Mechanical properties and chloride diffusion performance of sustainable concrete with LC3

Limestone calcined clay cement (LC3); Sustainable concrete; Mechanical properties; Chloride diffusion performance; Pore structure

As a kind of low-carbon cement, limestone calcined clay cement (LC³) has broad prospects in reducing cement energy consumption and carbon emissions, which has received widespread attention from researchers worldwide. LC³ concrete demonstrates comparable mechanical properties and improved durability, especially the chloride penetration resistance. In this paper, the mechanical properties of LC³ concrete using seawater and sea sand (SWSS) and recycled coarse aggregate were studied. The chloride diffusion performance of LC³ mortar was investigated. The results show that when the substitution ratio of LC³ is 35%, the overall mechanical properties of LC³ concrete are comparable to those of ordinary cement concrete, and LC³ concrete even exhibits higher compressive strength (Fig. 1), and the influence of LC³ on the stress-strain behavior of concrete is relatively small (Fig. 2). Meanwhile, sustainable concrete incoporating LC³, SWSS and recycled coarse aggregate can also obtain considerable mechanical properties (Fig. 1 and Fig. 3). When the replacement ratio of LC³ is 50%, the substantial reduction of cement clinker in the cementitious material will have a certain negative impact on the mechanical properties of the concrete. However, LC³ shows extraordinary resistance to chloride diffusion. Under the same conditions, the chloride ion penetration depth of LC³ mortar is reduced by nearly 80% compared to ordinary cement mortar (Fig. 4).



Mercury intrusion porosimetry (MIP) test of the concrete matrix was carried out, and the pore structure of the concrete was analysed. The obtained results reveal that the pore structure of concrete is significantly optimized through reducing the number of large pores (Fig. 5 and Fig. 6). LC³ concrete exhibits highly refined pore structure.