Effect of combining surfactant additives in extruded fiber cement reinforced with sisal fiber natura

Abstract

The incompatibility between sisal fibers and the cement matrix can pose a challenge in the production of fiber cement. To address this scenario, a combination of additives can be used to enhance the interaction between fiber and matrix, promoting more effective adhesion and improving the properties of fiber cement. The aim of this study was to produce fiber cement composed of 97% Portland CPV cement and ground agricultural limestone, 3% natural sisal fibers, along with 1% viscosity modifiers and 1% water-reducing additives, with samples identified as MV-RT_RA2, and due to the addition of 0.8% air entrainer (MV-RTRA2IA), and the addition of 0.6% lignosulfonate-based water reducer (MV-RTRA2RA1). The results indicated that sample MV-RTRA2IA exhibited the highest porosity value, reaching 21%. This was attributed to the addition of the air entrainer additive, which resulted in a heterogeneous distribution of pores and open fissures after the fracture of the cement matrix, as confirmed by SEM analysis. As for the modulus of rupture and elasticity, the highest values were found in sample MV-RTRA2RA1, with averages of 14.4 MPa and 7.8 MPa, respectively. All samples exhibit pores and fissures after the fracture of the cement matrix.