Silika Aerojel Katkılı Hibrit Silis Dumanı Harçlarının Mekanik, Por Yapısı,Termal İletkenlik ve Mikro Yapı Özellikleri

Çimento esaslı karışımlarda yüksek miktarda silika aerojel kullanımının çimento esaslı malzemelerin termalyalıtım özelliklerine üstün düzeyde katkı sunduğu iyi bilinen bir gerçektir. Bununla birlikte, günümüz koşullarındasilika aerojellerin üretim maliyeti geleneksel yalıtım malzemelerine kıyasla oldukça yüksektir. Bu çalışma, düşükkatkı oranlarında silika aerojel tozu içeren alkali-aktive edilmiş hibrit silis dumanı harç özelliklerineodaklanmaktadır. Bu amaçla aerojel katkı oranları çimento ağırlığınca %0, %0.25 ve %0.5 düzeylerinde tasarlandıve harç karışımlarının alkali aktivasyonu çimento ağırlığınca %0.1 ve %0.2 dozajlarındaki sodyum karbonat(Na2CO3) ile gerçekleştirildi. 2, 7 ve 28 günlük kür sürelerinin tamamlanmasından sonra, az miktardaki silikaaerojel ilavesinin hibrit harç numunelerinin mekanik, termal iletkenlik, por yapısı özellikleri ve mikro yapımorfolojisi üzerindeki etkisi ayrıntılı olarak araştırılmıştır. Deneysel sonuçlar, % 0.25 aerojel katkılı numunelerdemaksimum % 2.4'lük basınç dayanımı düşüşüne karşın numunelerin termal yalıtım özelliklerinin % 28 düzeyindegelişebildiğini göstermektedir. Hibrit silis dumanı harçlarında jel gözenek oluşumunun yüksek seviyesine (≈% 40)bağlı olarak, silika aerojel ilavesinin harç numunelerinin mekanik özellikler üzerindeki olumsuz etkisisınırlanmaktadır. Bu çalışma hibrit silis dumanı harç karışımlarında silika aerojellerin kullanımı hakkında yeni birbakış açısı sunmaktadır.

Mechanical, Pore Structure, Thermal Conductivity and Microstructure Properties of Silica Aerogel-Incorporated Hybrid Silica Fume Mortars

It is a well-known fact that the use of a high amount of silica aerogel in cement-based mixtures contributessignificantly to the thermal insulation properties of cement-based materials. However, the current manufacturingcost of silica aerogels is quite expensive compared to traditional insulating materials. This study focuses on theproperties of alkali-activated hybrid silica fume mixtures containing silica aerogel powder at a low content rate.For this purpose, aerogel inclusion ratios were designed at 0%, 0.25% and 0.5% by weight of binder and thealkaline activation of the mortar mixtures was carried out with sodium carbonate (Na2CO3) at dosage rates of 0.1%and 0.2%, by weight of binder. After 2, 7 and 28 days of curing, the effect of the inclusion of a small amount ofsilica aerogel powder on the mechanical, thermal conductivity, pore structure properties and microstructuremorphology of the hybrid silica fume mortar samples were investigated in detail. Experimental results show thatthe thermal insulation properties of the samples can be improved by 28% with a maximum compressive strengthreduction of 2.4% in 0.25% aerogel-Incorporated samples. Due to the high level of gel pore formation (≈40%) inhybrid silica fume mortars, the negative effect of silica aerogel addition on the mechanical properties of thesamples is limited. This study provides a new perspective on the use of silica aerogels in hybrid silica fume mortarmixtures.

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