Comparative study of the characteristics of nano silica - , silica fume - and fly ash - incorporated cement mortars

Abstract

The structural characteristics of cement mortars, impregnated with nano silica (NS), silica fume (SF) and fly ash (FA), were comparatively studied using Fourier transform infrared spectrometer (FTIR), thermogravimeter-differential thermogravimeter (TG-DTG) and scanning electron microscope (SEM). The mechanical strengths of the specimens were determined at early (7th day) and standard (28th day) curing ages. The compressive strengths and flexural strengths developed in the mortar specimens containing NS particles were found considerably higher than those of the corresponding specimens of SF and FA over and above the control at both ages. FTIR, TG-DTG and SEM analyses results were consistent with the remarkable increase in the mechanical strength of the mortars with NS. These increases in the strengths of the mortars with NS are attributable to the nano sized particles and extensive surface area of NS. The nano sized particles, as nucleating agents, promoted the hydration of C 3 S and C 2 S and the formation of C-S-H phase. Plenty of active sites on the surface of NS particles induced their pozzolanic reactivity and the extent of bond formation between NS particles and free CH.

Microstructural characterization of catalysis product of nanocement based materials: A review

“…SEM results reported in other previous study [31] shows that the microstructure of cement-based product partially replaced with NS was denser than cement-based product without the NS replacement because of the pozzolanic reaction by consumption of CH, and formation of additional C-S-H which fill the pores system and causing densification effect which improved the microstructure of cement system. A more compact microstructure image caused by pozzolanic reaction in cement-based products with replacement of nano silica was reported in the study done by another researcher [8].…”

“…The scope of this review is on two materials namely spent fluid cracking catalyst (SFCC and nanosilica (nS).The spent fluid cracking catalyst (SFCC) which is produced from the catalytic cracking in petroleum industry is an inorganic waste material [2][3] and its contribution in cement-based production can bring environmental and economic benefits, thus reducing the final cost of cement-based products and the environmental impacts related to cement production and can be used as partial cement or sand replacement [4][5]. The material can be classified as non-hazardous material [6]for cement replacement because it was found that low concentration of heavy metal that can leach out of the SFCC which gives higher confidence in its possible use as a construction material.Other researchers [7] stated that nano-materials have received wide attention for use in the constructions sector and the increasing in the performance has been discovered for these materials in terms of smart functions and sustainable characteristics [8]. Many studies have shown that the contribution of nano silica (NS) in cementitious systems especially in construction of cement-based products is by improving the characteristics of the plastic and hardened material [9].…”

Self-Healing Ability of High-Strength Fibre-Reinforced Concrete with Fly Ash and Crystalline Admixture

“…The broad band detected at 3711 cm -1 in the infrared spectroscopy of OPC linked to overlap stretching vibrations of both the structural and free hydroxy groups of CH and water respectively. FTIR spectra of RC, CA, FA20CA which have been defined as fingerprint evidence for the degree of polymerization with the formation of calcium-silicate-hydroxide phase due to hydration [24] having strong band observed at 900 cm -1 and the band observed at 520 cm -1 were associated with the bending-in-plane vibrations of the Si-O bonds in C3S (tricalcium silicates) and C2S (dicalcium silicates) [25][26][27][28]. The intensity of these bending-in-plane vibrations of the Si-O bonds decreased as calcium-silicate-hydroxide crystals formed [24,29].…”

Цементийн Гидратжилтын Бүтээгдэхүүнд Наноцахиурын Оксид Нэмэлтийн Үзүүлэх Нөлөө

“…Цахиурын тоос (Silica fume) ба бусад цахиурлаг нунтаг эрдсүүд нь цементийн гидратжилтын үед дүүргэгч нөлөө үзүүлж нүх сүвийг багасгах, поззолонжих урвалыг явуулж кальцийн гидроксидыг кальцийн гидросиликат болгон хувиргах, цементийг өндөр шинж чанартай, бат бэх сайтай болгох нөлөө үзүүлдэг. Өнгөрсөн 10 жилд 1-100 нм-ын хэмжээтэй наножижиг хэсгийн ер бусын шинж чанар нь судлаачдын анхаарлыг маш ихээр татаж байна [3][4][5][6]. Цементийн үйлдвэрлэлийн ялгаруулж буй нүүрсхүчлийн хий нь дэлхий нийт ялгарч буй нүүрсхүчлийн хийн 6-7 %-ийг эзэлдэг.…”

“…Иймд цементийн үйлдвэрлэлийг дэлхий нийтээр багасгах бодлоготой байна. Цахиурын тоос (silica fume), цахилгаан станцын үнс (fly ash), наноцахиурын оксидыг хэрэглэж нүүрсхүчлийн хийг ялгаруулахгүй цемент үйлдвэрлэх боломжтой [4,7]. Цементийн гидратжилтанд үүсдэг кальцийн гидросиликат нь өөрөө маш нарийн нанобүтэцтэй материал юм [5].…”