Development of High-Performance Sticky Rice–Lime Composite with Metakaolin and Hemp Fibers

Abstract

Sticky rice–lime mortar, a representative ancient binding material widely employed in construction applications across Asian countries, has been a subject of substantial academic research and development efforts for its restoration. However, conventional sticky rice–lime mortar is characterized by suboptimal strength and limited toughness, necessitating further enhancements to expand its practical utility. This study presents the formulation of a high-performance sticky rice–lime mortar by incorporating metakaolin and hemp fibers. A comprehensive investigation of various parameters influencing the compressive and flexural properties of the resulting composite was undertaken, encompassing the volume content of hemp fibers, the mass content of sticky rice paste, and the mass content of metakaolin. The experimental outcomes demonstrate the efficacy of metakaolin and sticky rice paste in significantly elevating the compressive strength of the sticky rice–lime composite. Notably, the presented sticky rice–lime mortar attains a remarkable compressive strength of up to 3.5 MPa, exceeding that of conventional sticky rice–lime mortar by more than threefold. Moreover, the introduction of hemp fibers effectively enhances the flexural strength of the sticky rice–lime composite through fiber bridging mechanisms. The research culminates by proposing a relationship equation, derived from the empirical data, to characterize the compressive and flexural strength of the high-performance sticky rice–lime composite. Overall, these findings emphasize the importance of optimizing sticky rice–lime mortar through the integration of advanced constituents, thus highlighting its potential as a durable and versatile binding material for historical preservation and sustainable construction practices within Asian contexts and beyond.