Mechanical and Microstructural Properties of Composite Mortars with Lime, Silica Fume and Rice Husk Ash

Abstract

A mixture of hydraulic lime and pozzolanic material can be used as a binder in making concrete and mortar for energy-efficient construction purposes. Generally, lime possesses lower strength and higher setting time. By introducing pozzolans in the lime mortar, their cementitious properties could be increased and could compete with the cement mortars. The use of pozzolan-lime binder in mortar reduces the utilisation of cement, and hence reduces the environmental problem originating from cement production. This study mainly deals with the mechanical and microstructural properties of lime and lime composite mortars made up of hydraulic lime, silica fume and rice husk ash. Three composite mortars were made with the following combination such as hydraulic lime-silica fume (LSF), hydraulic lime-rice husk ash (LRA) and hydraulic lime-silica fume-rice husk ash (LSR). Further, their properties were compared with the pure lime mortar. Preliminary investigations were made on the lime reactivity and pozzolanic reactivity tests. It was understood that silica fumes have a (15%) better reactivity than rice husk ash. The introduction of pozzolans in the lime mortar promotes fresh, hardened and microstructural properties. The 28 days’ compressive strength of lime composite mortars achieved more than 16 Mpa, while the lime mortar attained 4 Mpa. The combined effect of pozzolanic reaction, hydration and carbonation in the lime composite mortars achieved four times the strength of lime mortar at 28 days. A high peak of calcium carbonate was detected in lime mortar as a result of carbonation. The well-developed microstructure of calcium silicate hydrate and calcium hydroxide exhibits the formation of hydration products in the lime composite mortars as observed from a scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). Similar graphs of Fourier transform infrared spectroscopy (FT-IR) showed the presence of equivalent functional elements in all lime composite mortars.

Synthesis and effect of using silica fume particles on shear properties of basalt fibers‐epoxy composites

“…Based on the XRD results, it is observed that the obtained silica structure is generally amorphous, which is related to the rapid condensation of volatile silica and surface tension silicon in the phase transition 27 . The broad peak obtained at an angle of about 22° indicates amorphous silica with nanometer size, and this result was compared with similar articles, which all showed the same result 28,29 …”

“…27 The broad peak obtained at an angle of about 22 indicates amorphous silica with nanometer size, and this result was compared with similar articles, which all showed the same result. 28,29 F I G U R E 1 The size distribution of synthesized silica particles in, (A) 250,000, (B) 150,000 times magnifications.…”

A Review on Partial Replacement of Cement in Concrete by Three Supplementary Materials

“…Similar conclusion was also drawn in a study where the density of RHA concrete found same for all replacement level (Ephraim et al, 2012). Lime based concrete also exhibited the (Malathy et al, 2022). However, some contradictions in the results were also noticed due to fact that there are various types of lime and their properties differ significantly.…”

Study on Flexural Behaviour of Ferrocement Composites Reinforced with Polypropylene Warp Knitted Fabric

“…The scale range used in the SEM analysis was 5 µm with the resolution of 5000x. The samples were examined in the SEM instrument [ 46 , 47 , 48 , 49 , 50 ]. After the flexural strength test, mortar bonded with the fabrics was taken out from the ferrocement composites.…”