No abstract

Fibre-reinforced cementitious composite (FRCC) is a type of composite that uses high volume of fibres to attain ductile properties. In this research, the effects of two different fibres, namely polyvinyl alcohol (PVA) and basalt, on the mechanical properties of FRCC such as compressive, splitting tensile and flexural strengths were investigated. The fibres were used in varying volume fraction, which includes 1.0%, 1.5% and 2.0% and a hybrid combination of 1.5% basalt fibre with 1.5% PVA fibre for the preparation of the FRCC. The results showed that while the fibres had minimal effect on the compressive strength of FRCC, significant improvements in the splitting tensile and flexural strengths were found. In the comparison of the flexural performances, the introduction of PVA fibre in FRCC led to superior properties and it exhibited more ductile failure mode compared with basalt fibre and the optimum fibre dosage to be added was determined to be 1.5%.

This study aims to develop a type of fine-grained lightweight concrete, also known as lightweight cementitious composite (LCC), containing perlite microsphere (PM) and fibres with enhanced impermeability. The effect of polypropylene (PP), polyvinyl alcohol (PVA), and basalt fibres on the fresh and hardened properties of LCC was investigated. Besides, silane-based water repellent admixture was incorporated to reduce the water absorption and enhance the hydrophobicity of LCC. The dry densities of LCC developed were in the range of 912–985 kg/m3. PP fibres have lesser influence on the strengths of LCC. However, PVA fibres enhanced the strength of LCC by up to 35.2% and 28% in the compressive strength and flexural strength, respectively, while the basalt fibres increased both strengths up to 30.1% and 43.5%, respectively. By considering the overall performance, LCC with 0.5% PVA fibres has achieved a good balance in workability and strength. Additionally, silane-based water repellent admixture had an excellent effect in reducing the water absorption and improving the hydrophobicity of LCC. By incorporating 1% of silane-based water repellent admixture, the LCC with 0.5% PVA fibres obtained water-resistant properties with the softening coefficient of 0.85 and water contact angle of 128.2°. In conclusion, a combination of PVA-LCC with 1% waterproofing admixture showed the best performance in terms of mechanical strength as well as hydrophobic properties and had the potential to be used in the fabrication of concrete façade.

This research describes the properties of acrylic fibre-reinforced cementitious composite containing high-volume fly ash. In this investigation, the fly ash content (30% and 60%) and the acrylic fibre dosage (0%, 1% and 2%) were varied. Increased content of fly ash in the composite was found to be able to partially compensate the reduction in workability caused by the inclusion of fibres. On the other hand, although the use of fibres had minimal influence on the compressive strength, the fibres could significantly enhance the flexural strength of the composite, particularly in the composite containing higher fly ash content. At elevated temperatures, it was found that the inclusion of acrylic fibres was beneficial in the composite with higher fly ash content, as demonstrated by the increased strength retention and reduced spalling damage at elevated temperature.

This preliminary work explores the possibility of utilizing perlite microsphere (PM) in producing lightweight cementitious composite (LCC). With the use of PM, LCC with dry density of about 1400 kg/m3 (35% reduction in density compared to normal cement mortar) can be obtained. Satisfactory compressive strengths of 32.6–34.5 MPa could be attained by the PM LCC, without and with supplementary cementitious materials such as silica fume and ground granulated blast furnace slag. The specific strength (compressive strength/density ratio) of LCC was also similar as the normal cement mortar. In addition, there was little difference in the flexural strength and drying shrinkage of PM LCC compared to normal cement mortar. Furthermore, similar flexural load–displacement behaviour was found between thin plate specimens produced with alkali-resistant glass fibre mesh reinforced LCC and that of normal cement mortar. In overall, this suggests that PM has the potential to be utilized as lightweight filler in producing LCC.