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Showing 1 to 13 of 13 for “"C-(A)-S-H"”.
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Influence of calcium-(alumino)-silicate-hydrate nanostructure on viscoelastic behavior
Viscoelasticity in concrete has been studied since the early 20th century with continuously advancing technology and methods. Currently, calcium-silicate-hydrate (C-S-H) is thought to be the phase responsible for viscoelasticity in concrete. Advances in small-scale mechanical testing in the past …
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Characterization of calcium-silicate-hydrate and calcium-alumino-silicate-hydrate
The primary objectives of this thesis were to synthesize calcium silicate hydrate (C-S-H) and calcium aluminosilicate hydrate (C-A-S-H) and characterize their structures with varying Ca/Si ratios and aluminum content. As a secondary objective, carbonation behavior in synthesized C-S-H was studied. …
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Understanding the role of calcium on the reaction mechanism of geopolymer cements through addition of nucleation seeds
Geopolymer cement is an innovative binder proposed by Davidovits as an alternative to conventional Portland cements for construction use. It is made from minimally processed industrial byproducts (fly ash, slag) activated by a low concentration alkaline solution (Na, K) and cured at room …
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Stabilisation of clay subgrade soils using ground granulated blastfurnace slag
Roads constructed on expansive clays may be adversely affected by the behaviour of the clay. Expansive clays suffer volume change due to changes in moisture content which causes heaving, cracking and the break up of the road pavement. Stabilisation of these types of soil is necessary to suppress …
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Mechanical Properties and Environmental Performance of Calcium Carbide Residue-Based Materials in Soil Stabilisation
This study systematically investigated three types of calcium carbide residue (CCR)-based materials for sustainable soil stabilisation, including CCR alone, CCR combined with fly ash (CCR-FA), and CCR-FA activated by a waste glass-derived alkaline activator. A series of microstructural analyses, …
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Toward antiquity-inspired design in materials and construction: Insights into the production and durability of the ancient materials Egyptian blue and Roman concrete
With increasing pressure on the global climate, there is a dire need to reduce the impact of both resource use and production of manufactured materials. In particular, modern ordinary Portland cement is responsible for up to 8% of global greenhouse gas emissions and offers a design life on the …
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Structure and Mechanical Properties of Cement and Intermetallic Compounds via ab-initio Simulations
Calcium silicate hydrates comprise a class of minerals formed synthetically during Portland cement hydration or naturally through various geological processes. The importance of these minerals is immense since they are the primary binding phases for Portland cement derived construction materials. …
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Setting and nanostructural evolution of metakaolin geopolymer
Geopolymers are being promoted as a sustainable alternative to the ordinary cements mainly because their production is associated with much less CO2 emissions. They also show advantages including compressive strength comparable to portland cements, high temperature resistance, and stability under …
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Irradiated recycled plastic as a concrete additive for improved chemo-mechanical properties in hardened cement pastes
Portland cement based concrete production contributes heavily to greenhouse gas emissions. Thus a need exists for the development of durable and sustainable concrete with a lower carbon footprint. This can be achieved when Portland cement is partially replaced with another material without …
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Mix design, fresh and hardened properties and microstructural characterisation of alkali-activated concrete based on PFA/GGBS blends
Alkali-activated concrete (AAC) has recently emerged as a potential candidate to replace the conventional Portland cement concrete (PCC) in several applications due to its low CO2 footprint and promising mechanical properties. However, the robustness and the good reputation PCC has gained over the …
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Factors influencing the strength development in pfa-lime systems
Pulverised fuel ash (pfa) has been mixed with lime and water, pressed into cylinders, and cured in 100% r.h. at temperatures of 50°C, 75°C and 95°C for times of between 30 minutes and 28 days.<br/><br/>The expansion of the cylinders and their unconfined compressive strengths have been measured at …
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Setting and nanostructure of slag-fly ash binders
Slag fly ash binders (SFB) are room temperature hardening binders that have high strength, reasonable setting time, and lower carbon footprint when compared to ordinary Portland cement (OPC). The precursors for SFB are industrial byproducts, namely slag and fly ash. The inexpensive nature of the …
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The performance of a blended PFA/GGBS alkali-activated concrete using a silica fume-based activator
The construction industry is currently tackling a serious concern with the ever-increasing use of Portland cement and associated carbon emissions due to urban development expansion worldwide. Hence, extensive research has been undertaken into ‘’’cement-free’’ alternative concrete has emerged in the …