Two types of cement-based functional composites, thermal insulation and acoustical insulation materials, have been developed and characterized in this thesis....[ Read more ]

Two types of cement-based functional composites, thermal insulation and acoustical insulation materials, have been developed and characterized in this thesis.

For thermal insulation material, paraffin and foam plastic beads had been incorporated into a short fiber reinforced cementitious composite. The extrusion technique is utilized to manufacture the composite panels. A series of heat transfer tests under both steady and transient condition is performed by using a controlled-environment multi-test facility. A combined conduction-convection system is arranged in the tests to evaluate the effect of paraffin and foam incorporation. The test results have proved that the foam can reduce the overall thermal conductivity of the composites and the paraffin can enhance the thermal capacity of the materials during transient period. These lead to a good heat insulation property.

For acoustical insulation material, lead spheres coated with silicone rubber are used as coarse aggregates. The lead ball is a heavy mass and the silicone rubber behaves as a soft spring. The coated lead spheres are embedded into a short fiber reinforced cement-based matrix. When a sound wave passes through the composite panel, localized excitation occurring in the coated lead balls will be induced. And thus the sound transmission through the panel can be greatly reduced. Therefore, the composite panel improves acoustical insulation by the localized resonant excitation.