The effect of Portland cement inclusions in hybrid glass fibre reinforced composites based on a full factorial design

Abstract

The apparent density, flexural modulus and strength of hybrid laminated composites were investigated through a full-factorial Design of Experiment (DoE) approach. Laminates were manufactured by hand lay-up using nine layers of glass fibre cross-ply fabric with an epoxy matrix phase reinforced with Portland cement microparticles. A first experiment investigated the effect of the inclusion site (particles in upper four layers, lower four layers, all layers or none), curing time (7 and 28 days) and compaction method (vacuum or uniaxial pressure). The fibre-matrix volume fraction and the particle mass fraction were fixed at 48.6/51.4% and 10% respectively. A second experiment investigated two distinct fibre-matrix volume fractions (48.6/51.4 and 29.6/70.4%) and five particle mass fractions (0, 2.5, 5.0, 7.5 and 10 wt%). Particle inclusions were restricted to the upper four layers, with 28 days of curing time and uniaxial compaction. The results were analysed via Analysis of Variance (ANOVA). A significant increase in flexural modulus and strength was observed at 28 days of curing time. Enhanced mechanical properties were obtained for laminates with particle inclusions only in the upper half of the structure, manufactured with 48.6/51.4% fibre-matrix volume fraction and uniaxial pressure. Higher flexural strength was achieved for composites manufactured with 51/49% fibre-matrix volume fraction and 2.5% of particle mass fraction. These fibrous-particulate hybrid composite laminates can be considered for future secondary structural parts in lightweight engineering applications.

Hybrid bio-composites reinforced with sisal-glass fibres and Portland cement particles: A statistical approach

“…In general, its behaviour is similar to that obtained for the flexural modulus presented in Figure 3 Figure 11. This behaviour can be attributed to the presence of particles in the interlaminar region, which contributes to retard crack propagation, as reported in literature [11,[26][27]. configuration appears to provide promising properties for sustainable structural applications.…”

“…Higher stiffness was obtained when 10wt% of cement microparticles were added. The mechanical behaviour of hybrid glass fibre reinforced composites with cement inclusion was also investigated by Melo et al [26] and Torres et al [27]. Melo et al [26]…”

Evaluation of the stiffening mechanism based on micro-sized particle inclusions in laminated composites

“…This phenomenon is controversial in the literature, especially when micro-sized particles are considered. An increase in flexural stiffness and a reduction in strength and toughness are commonly reported 1,3,15,17,27,28 . In general, the mechanisms of improvement are attributed to the stiffening of the matrix phase and the shear interlocking effect.…”

Investigations on sustainable honeycomb sandwich panels containing eucalyptus sawdust, Piassava and cement particles

“…Melo et al [19], Torres et al [20] and Ribeiro Filho et al [21], leading to an increase in mechanical properties. Melo et al [19] reported that the cement particles increased flexural strength and flexural modulus of glass fibre reinforced composites. Higher mechanical properties were observed at 28 days of cure time, especially in those composites produced with 2.5 wt% of cement particles.…”