Chemical and Engineering Properties of Blended Cement Containing Micro- and Nano-silica

Abstract

Nano-technology (NT) and nano-materials (NMs) has attracted considerable scientific attention, due to the new potential uses of nano-particles (NPs), which can change the concrete world. There is a great interest in replacing a long time used materials in concrete structure by NMs to improve the different properties of concrete. In this study, the hydration characteristics and microstructure of cement pastes and mortars with and without nano-silica (NS) were studied. Blended cement mix containing 10 mass, % silica fume (SF) was prepared, then the cement mix was partially replaced by NS up 1.5 mass, %. The results show that, NS increases the water of consistency and final setting time The values of chemically combined water, free lime, bulk density and compressive strength prove that, NS up to 1% seems to be an effective mineral additive for blending with OPC to improve its chemical and engineering properties. This is mainly attributed to that; NS behaves not only as filler to improve microstructure, but also as pozzolanic material (PZM). The formation of more hydrated silicates in presence of NS was confirmed by XRD, DTA, IR and SEM examinations. At 1.5 mass, % NS, the density and strength are reduced but still higher than those of 0.0 and 0.5% NS. Also, the results indicate that, the substitution of blended cement mix (OPC+10% SF) with 1 mass, % NS gives a reasonable hydration characteristics and improved engineering properties more than those of 0.0 and 0.5% NS at all hydration ages up to 90 days. Therefore, this level of NS is suggested to be the most suitable replacement level.

Surface Treatment of Cement based Composites: Nano Coating Technique

“…Nevertheless, additional hydration products were gained during the pozzolanic activity between nano oxides and calcium hydroxide from cement hydration as indicated in SEM and XRD images. However, the results are agreeable with those of obtained by Ahmed et al (2017). It is therefore concluded from Figure 7 to 10 that the nanoparticles chemically reacted with CH produced during the hydration of cement.…”

Eco-friendly concrete pavers made with Silica Fume and Nanosilica Additions

“…La incorporación de micro y nanopartículas de sílice en el hormigón mejoran el efecto de relleno (empaquetamiento) y distribución del tamaño de partícula [10], disminuyendo así la porosidad en el concreto y aumentando la reacción puzolánica con el hidróxido de calcio (Ca (OH)2 o CH) para producir gel csh (silicato de calcio hidratado), especialmente en la zona de transición interfacial (itz) entre la pasta de cemento y el agregado, con lo cual se consigue aumentar la resistencia mecánica del hormigón, (especialmente en los primeros días), su durabilidad e impermeabilidad [11]. Las partículas de nano y microsílice llenan los vacíos de la estructura del gel csh y actúan como núcleo para unirse fuertemente con otras partículas del mismo gel [12].…”

Nano SiO2 Katkılı Çimento Harçlarının Mekanik Özelliklerine Yüksek Sıcaklığın Etkisi

“…Bu bağlamda nano SiO2'in çalışmalarda düşük oranlarda kullanıldığı görülmüştür. El-Didamony Ahmed ve ark (2017)'na göre %1'e kadar nano SiO2 kullanımı portland çimentosunun kimyasal ve mühendislik özelliklerini geliştirmektedir (El-Didamony Ahmed, 2017). Sonebi ve arkadaşlarına (2015) göre taze harçların yoğunluğuna bakıldığında en uygun nano SiO2 oranının %1.7 olduğu tespit edilmiştir (Sonebi et al, 2015).…”