Mechanical and durability properties of hybrid natural fibre reinforced roadbed foamed concrete

Foamed concrete is widely used in road engineering as it has numerous advantages. However, limitations, such as low strength, inadequate frost resistance, poor water erosion resistance, and sensitivity to temperature fluctuations, restrict its performance. To overcome these challenges, natural fibres with distinct properties are incorporated into the concrete to enhance its strength, durability, and eco-friendliness, aligning with the requirements of the construction industry. This study investigated the mechanical properties, durability, and microscopic characteristics of hybrid natural fibre-reinforced roadbed foamed concrete (HNFRRFC). A wet density of 600 kg/m3, different volume fractions (0.15 %, 0.43 %, and 0.45 %) of basalt fibre and coir fibre, and diverse mix ratio designs (1:2, 1:1, 2:1) were considered experimentally. The results show that the optimal fibre content and mix ratio are 0.3 % and 1:2, respectively, which enhanced the maximum strength of the concrete. All mix ratios demonstrated improved strength and durability, and a microscopic property analysis revealed the underlying mechanisms behind the augmented mechanical properties and durability of the HNFRRFC specimens. Thus, incorporating hybrid natural fibres offers an effective means of increasing the strength, durability, and microscopic attributes of foamed concrete used in roadbed applications.