CAF is considered the least reactive main clinker phase, but its reactivity may be affected by adding supplementary cementitious materials (SCMs). Pure CAF was synthesised in a laboratory furnace, and the role of silica fume without gypsum on its early hydration properties was monitored. Burning was carried out in four stages to achieve 99% purity of CAF. Heat flow development was monitored by isothermal calorimetry over 7 days of hydration at 20°C and 40°C. The role of silica fume on hydrogarnet phase katoite (CaAl(SiO) (OH) x = 1.5-3) formation during early hydration was studied. Rapid dissolution of CAF, formation of metastable C-(A,F)-H and its conversion to C(A, F)H was evidenced by isothermal calorimetry as a large exotherm. Changes in microstructure during early hydration were documented by SE micrographs, EDS point analyses, X-ray mapping and line scans by SEM-EDS. The phase composition was characterised by DTA-TGA and QXRD after 7 days of hydration. The katoite diffraction pattern is similar for the reference sample and sample with silica fume, but substitution in its structure can be revealed by X-ray microanalyses. The composition of katoite is variable due to the various extent of substitution of 4OH by SiO due to silica fume.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1111/jmi.13280 | DOI Listing |
Sci Rep
December 2024
Civil Engineering Department, Shoolini University, Solan, Himachal Pradesh, 173229, India.
Geopolymer concrete (GPC) offers a sustainable alternative by eliminating the need for cement, thereby reducing carbon dioxide emissions. Using durable concrete helps prevent the corrosion of reinforcing bars and reduces spalling caused by chemical attacks. This study investigates the impact of adding 5, 10, and 15% silica fumes (SF) on the mechanical and durability properties of GPC cured at 60 °C for 24 h.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Department of Civil Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia.
The formulation of binary, ternary, and quaternary supplementary cementitious materials (SCMs) on an optimized silica fume amount using fly ash, ultrafine (MQ), and limestone powders (LS) is the most sustainable approach to recycling these types of solid wastes for durable concrete. The optimum replacement level of 10% silica fume was blended with different replacement levels of 5, 8, 10, and 15% MQ to formulate different ternary mixes to evaluate the filling effect of MQ. Different ternary mixes containing 10% silica fume and 5, 10, and 15% LS were also produced to examine the effectiveness of both ternary mixtures with either MQ or LS.
View Article and Find Full Text PDFHeliyon
October 2024
Department of Building Engineering and Construction Management, Khulna University of Engineering and Technology, Khulna, 9203, Bangladesh.
This study investigates the use of various industrial waste materials-silica fume (SF), cement kiln dust (CKD), calcium carbide residue (CCR), rice husk ash (RHA), and ground granulated blast furnace slag (GGBS)-as eco-friendly stabilizers for expansive clay soil (ECS). Laboratory tests were conducted to assess the impact of different proportions (3 %, 6 %, and 9 %) of these additives on the soil's physical, mechanical, and microstructural properties. Results indicated that the inclusion of industrial waste significantly improved the soil's behavior, with notable reductions in liquid limit (up to 37.
View Article and Find Full Text PDFHeliyon
November 2024
School of Civil Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
Conventional cement production is a major source of CO emissions. As a result, there is an increasing emphasis on finding sustainable alternatives for cement and their appropriate proportion in concrete. This investigation explores the optimization of supplementary cementitious materials (SCM) like ultrafine fly ash (UFFA) and silica fume (SF) content in high-performance concrete (HPC).
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Universidad Autónoma de Nuevo León, Facultad de Ingeniería Civil, San Nicolas de los Garza 66455, Nuevo León, Mexico.
As awareness of the impact of anthropogenic activities on climate change increases, the concepts of durability, resilience, and sustainability in concrete tend to be adopted more seriously in the concrete construction industry. In this sense, one of the concrete technologies that began in the 1980s and that significantly contributes to maximize the beneficial effect on all these concepts are the ultra-high-performance concretes, a very attractive technology because it presents ultra-high strength and durability performances far superior to those of conventional concretes, a performance that is leading to a permanent increased demand. However, the development of these concretes has been widely criticized due to their high ecological impact, which is mainly attributable to the high cement dosages required for their production (800-1000 kg/m).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!