Mechanical and micro-structural investigation of multi-scale cementitious composites developed using sisal fibres and microcrystalline cellulose

Abstract

This research work attempts, for the first time, to use sisal fibres and microcrystalline cellulose (MCC) in combination for developing multi-scale cementitious composites with improved strength, modulus as well as fracture energy. MCC (0.1% to 3.0 wt.%) was first dispersed in water with the help of Pluronic F-127 surfactant (20% of MCC wt.) using ultrasonication and subsequently, the MCC suspensions were added to cement-sand mixtures containing sisal fibers (0.25 to 2 wt.% of cement). Visual observation, UV-Vis analysis and optical microscopy suggested that ultrasonication for only 15 min led to homogeneous MCC suspensions without significant sedimentation and Pluronic significantly reduced the total agglomerated area and the average MCC particle size in the suspensions. The use of up to 2 wt.% sisal fibres (without MCC) increased the fracture energy of cementitious composites by 351% (after 28 days hydration) but reduced the compressive and flexural strengths by 38% and 13%, respectively. On the contrary, MCC (without sisal fibres) could strongly improve the compressive strength (20.5% using 0.1wt.% MCC) but was not found so effective in improving the fracture energy (improved by 29% using 0.1 wt.% MCC). However, multi-scale reinforcements containing 0.1 wt.% MCC and 0.25-0.5 wt.% sisal fibres led to improvements of up to 18.4%, 30.1%, 30% and 100% in the compressive strength, flexural strength, flexural modulus and fracture energy of composites, presenting distinct advantages over only sisal fibre or MCC-based reinforcements. The results indicated the formation of higher amount of hydration products in multi-scale composites due to the positive effect of MCC on cement hydration. Superior hydration in the multi-scale composites resulted in a denser microstructure with a lower pore size and an improved fibre-matrix interface, improving significantly the strength, modulus and fracture energy.

A Critical Review on Modification Methods of Cement Composites with Nanocellulose and Reaction Conditions during Nanocellulose Production

“…Such a trend may affect the workability and compaction of the material. Other authors also noted this behavior, among others [ 52 , 106 ]. The most significant percentage decrease in the size of the flow diameter was recorded for CNC labeled C2 at a dose of 1.5% and was 42% and the smallest for C1 at a dose of 0.25%, amounting to 5%, compared to the reference mortar.…”

[Retracted] Experimental Study of Thermal and Mechanical Behaviour of Graphite‐Filled UJF Composite

“…e fibers traditionally used were carbon, glass, and others. e plastics reinforced with sisal [10,11], jute [12,13], bamboo [14], and porcelain fibers [15], amongst the natural fibers, have attracted attention for their low cost compared to man-made fibers [16,17]. Graphite is a pure carbon in crystalline form, very similar to mica sheets formed tightly by bound atoms [18,19].…”

Mechanical properties of cellulose‐based multiscale composites: A review

“…On the other hand, per cent sisal fibers improved flexural strength of composites by up to 30.1%, representing discrete advantages over only MCC-based (or) sisal fiber reinforcements. [120] 5.2.10 | Flexural properties of cellulose (jute) based multiscale composites Muhammad Muslim Rehman flexural properties of MCC/Jute fiber reinforced Bio-epoxy composites. Flexural strength was improved by 52%wt when MCC particles were added at 7 wt%.…”