Degradation characteristics of foamed concrete with lightweight aggregate and polypropylene fibre under freeze-thaw cycles

摘要

The growing use of foamed concrete for building materials and geotechnical fills raises the question of suitable durability and performance standards. In order to analyse the degradation characteristics of foamed concrete with lightweight aggregate and polypropylene fibre under freeze-thaw cycles, specimens are frozen and thawed in a temperature and humidity-controlled container where the temperature varied from +40 to -40°C and the humidity was kept constant (about 100%). The freeze-thaw tests are performed; they consist of around 40 cycles of freezing and thawing, with each cycle lasting 8 h. The deterioration of the specimens is examined according to changes of strength and deformation characteristics in a series of uniaxial compression tests. The experimental results show that: (a) the compressive strength of samples decreases and the axial strain corresponding to the peak stress increases with increasing of freeze-thaw cycles, and the compressive strength decays exponentially with the number of freeze-thaw cycles; (b) the compressive strength of foamed concrete decreases with increase in foam and perlite content, increases with increased polypropylene fibre content; their fitting relationship is also provided.