Abstract: Utilizing an orthogonal experimental design, we evaluated the primary properties of 16 groups of thermal insulation concrete mixed with straw, polypropylene fiber and glazed hollow beads as well as three groups of concrete mixed with merely glazed hollow beads. Further variance and range analysis examined the impact of three significant factors on the compressive and splitting tensile strengths of cubic specimens. The three factors include: volume fraction of straw powder (V_S), sand-replacing glazed hollow bead ratio (V_G), and volume fraction of polypropylene fiber (V_P). Our findings reveal that incorporation of glazed hollow beads enhances the concrete’s thermal insulation properties and workability yet results in diminished strength. Notably, glazed hollow beads significantly reduce the compressive strength of concrete, with observed maximum losses reaching 24.64%. Meanwhile, the impacts of straw powder and polypropylene fiber on compressive strength proved to be minimal and can be neglected. In contrast, polypropylene fiber markedly reinforces the tensile strength, inducing a maximal increase of 16.72% and a substantial improvement in the tension-to-compression ratio. Regression analysis of the experimental outcomes facilitates the development of predictive models for both compressive and tensile strength of the concrete mixed with straw, polypropylene fiber and glazed hollow beads, yielding promising predictions.

Key words: thermal insulation concrete, straw, polypropylene fiber, glazed hollow beads, mechanical properties, orthogonal experiment, strength prediction model