Hybrid Fiber-Engineered Cementitious Composites (HFECCs) for Pavements: Performance and Application Insights

Engineered Cementitious Composites (ECC) show a great potential utilization in pavement engineering due to its excellent ductility and flexural tensile performance. To meet the requirements of pavement engineering, a hybrid fiber ECC (HFECC) incorporating polyethylene fiber (PE) and steel fiber (ST) was developed to balance the compressive strength, flexural tensile strength, fluidity, and ductility. As ST content decreases from 2.5% to 1.25%, and PE content increases from 0% to 1.25%, the compressive strength and fluidity of HFECC decrease, while flexural toughness and ultimate tensile strain increases. A balance index was proposed to determine the optimal fiber content of HFECC for pavement engineering. HFECC with 2.0% ST and 0.5% PE has the best balance performance in compressive strength, ductility, and fluidity. Furthermore, to enhance cost efficiency and promote HFECC application in pavement engineering, a plain cement concrete (PCC)-HFECC composite beam was designed, and a cost efficiency indicator was introduced to determine the optimal thickness coefficient of PCC-HFECC composite beam for pavement engineering. The effect of HFECC thickness coefficients (0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8) on the flexural tensile performance of the composite beam was evaluated. The flexural tensile strength and the thickness coefficient of the PCC-HFECC composite beam could fit with a parabola model. As the thickness coefficient increases, cracks initiation shifts from the bottom of PCC layer to the bottom of HFECC layer. PCC-HFECC composite beam exhibits a higher cost efficiency than PCC, and PCC-HFECC composite beams with a thickness coefficient of 0.5 is recommended for pavement applications.