Engineering Commons^™

Utilization Of Biomimetic Molecules To Control The Carbonation Of Cementitious Phases, Muhammad Intesarul Haque

Civil Engineering Dissertations

This study introduces an innovative approach to mitigate carbonation-induced degradation of C-S-H and to enhance the carbonation properties of low calcium based cementitious materials by utilizing specific biomimetic molecules. In this study, four different biomimetic molecules were utilized. Details about their chemical formula and chemical structure can be found in Chapter 1. The dissertation is broadly focused on two aspects, Part 1 (Chapter 2 and 3) evaluated the role of biomimetic molecules in reducing the carbonation degradation of C-S-H. Part 2 (Chapter 4 and 5) assessed the effectiveness of the biomimetic molecules as performance enhancing admixture of carbonation cured dicalcium …

Effect Of In-Situ Formed Nano-Calcite Particles On Hydration And Properties Of Cement-Based Materials, Bowen Tan

Masters Theses

The in-situ preparation of nano-calcite via bubbling method and the effects of the nano-calcite on the hydration process and properties of the cement-based materials are investigated in this research. The nano-calcite is synthesized under different conditions and added into Portland cement to prepare test samples. The bubbling method is then introduced in upcycling the municipal solid waste incineration (MSWI) ashes, and the effects of the upcycled MSWI ashes on the hydration of Portland cement is investigated. Experimental results illustrate that the COâ‚‚ bubbling method can produce nanometer-to-sub- micron-sized calcite particles, and the synthesis rate and the morphology of the nano-calcite …

Role Of Binder Compositions And Carbonate Polymorphs On The Performance Of Carbonation Activated Cementitious Composites, Mohammad Rakibul Islam Khan

Civil Engineering Dissertations

The most energy-intensive manufacturing industry in the US is the Ordinary Portland Cement (OPC) industry. This industry is responsible for 5-8% of global CO2 emissions caused by humans. The calcination of limestone to produce high lime calcium silicate and high manufacturing temperature (1450°C) are responsible for this significant amount of CO2 emissions. This CO2 footprint of the cement-based composites can be decreased by utilizing cementitious materials with low-lime calcium silicate. Low-lime calcium silicates are typically semi-hydraulic or non-hydraulic. As a result, it is necessary to activate those materials in order to increase their reactivity. Alkali activators, carbonation curing (CO2 curing), …

Utilization Of Low-Lime Calcium Silicate In Hydrated And Carbonated Cementitious Materials, Mohammad Rakibul Islam Khan

Electronic Theses and Dissertations

This study investigated the potential application of wollastonite as a cementitious material in both hydrated and carbonated binder systems. Wollastonite is naturally occurring low-lime calcium silicate (CaO.SiO₂) mineral with a substantially lower carbon footprint compared to the ordinary Portland cement (OPC). The first part of this work presented the application of wollastonite as partial replacement of OPC in traditional hydrated cement-concrete system. Second part of this work evaluated the properties of carbonation activated binder produced using wollastonite as the primary ingredient.

For the first part of the thesis, ground wollastonite with 3.5 µm and 9 µm mean particle …

Micro-Mechanical Analysis Of Corrosion Products Formed During Long-Term Carbonation Induced Corrosion Of Steel, Marijana Serdar, Dubravka Bjegovic, Valérie L’Hostis, Stéphane Poyet, Damien Féron

International Conference on Durability of Concrete Structures

During corrosion distinct types of corrosion products form, composed of different ratios of ferrous ions and oxide, hydroxides. Corrosion products have different physical and mechanical properties, mainly density, resistivity, volume and modulus of elasticity compared to iron. Knowing properties of corrosion products is indispensable for service life modelling of structures and can give valuable insight into the long-term corrosion propagation process. In this study micro-indentation method was used to evaluate mechanical properties of different layers formed during long-term carbonation induced corrosion of steel in concrete. Investigation was performed on three sets of reinforced concrete samples, that underwent corrosion during 50, …

Influence Of Cracks On The Carbonation Resistance Of Concrete Structures, Abbas Al-Ameeri Mr., Muhammed Imran Rafiq Dr., Orania Tsioulo Dr.

International Conference on Durability of Concrete Structures

Carbonation-induced corrosion of steel rebar embedded in concrete is one of the major issues influencing durability of reinforced concrete structures. It has been acknowledged that structural cracks in concrete influences the carbon dioxide (CO₂) diffusivity and accelerates the carbonation-induced reinforcement corrosion, however most of the previous studies on the carbonation induced corrosion have concentrated on the un-cracked / unloaded concrete. This study investigates the impact of cracks caused by loading on the depth of carbonation into concrete. Concrete prisms (100x100x500 mm) were subjected to four different crack widths (0, 0.05-0.15 mm, 0.15-0.25 mm and 0.25-0.35 mm) and the …

New Model For Natural Carbonation Prediction In Reinforced Concrete – Concept And Validation On Chemical Admixtures, Stephen O. Ekolu, M Raats

International Conference on Durability of Concrete Structures

A new model for prediction of natural carbonation in reinforced concrete structures has recently been developed and presented in (Ekolu, 2018). For brevity, the model is referred to as ESS model. It employs concrete strength as the primary property depicting core carbonation behaviour of any given concrete while other factors induce secondary influence. Chemical admixtures in concrete significantly influence concrete behaviour. Using experimental data from the literature (Dan-Herrera et al., 2015), the model behaviour is verified under use of various types of chemical admixtures of concrete including internal curing, shrinkage reducing, viscosity modifying, and high range water reducing admixtures. Class …

Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener

International Conference on Durability of Concrete Structures

This work presents the results of an investigation carried out to assess durability of concrete made with a calcined clay- limestone-Portland cement with 47% of clinker, hereafter named LC3, produced during an industrial trial in 2013. LC3 was used to cast concrete blocks and later expose them at a natural location at the northern coast of Cuba. Reference concrete was cast with Cuban Portland cement having 88% of clinker. Throughout three years (2015, 2016, 2017) concrete cores were systematically taken and the specimens were subjected to a testing program that included Formation factor, chloride profiling, surface resistivity, air permeability and …

Progress Of Carbonation In Chloride Contaminated Concretes, Yaocheng Wang, P. A.M. Basheer, S. Nanukuttan, Y. Bai

International Conference on Durability of Concrete Structures

Concretes used in marine environment are generally under the cyclic effect of CO₂ and chloride ions (Cl^-). To date, the influence of carbonation on ingress of chloride ions in concretes has been widely studied; in comparison, study on the influence of Cl^- on the progress of carbonation is limited. During the study, concretes were exposed to independent and combined mechanisms of carbonation and chloride ingress regimes. Profiles of apparent pH and chloride concentration were used to indicate the progress of carbonation and ingress of Cl^- in concretes. From the apparent pH profile, a carbonation front …

Co2 Sequestration In Cement-Based Materials During Mixing Process Using Carbonated Water And Gaseous Co2, Jacek Kwasny, P. A. Muhammed Basheer, Mark I. Russell, William Doherty, Kieran Owens, Neil Ward

International Conference on Durability of Concrete Structures

This paper presents selected findings from a recently completed research project, aimed at the investigation of CO₂ sequestration in cement-based materials during the early stages of hydration when the cement paste is being mixed. Portland cement pastes were carbonated during the mixing process, using both carbonated water and gaseous CO₂, and their properties were compared to the control non-carbonated mix. All mixes were prepared in a purpose-designed chamber that permitted carbonated water and gaseous CO₂ to be mixed with the cementbased materials during the mixing process, without losses of CO₂ to the external environment. Temperature …