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With the global population on the rise, the construction industry has experienced significant growth in the last two decades. Cement, a key component in concrete production, contributes up to 8% of total CO2 emissions. This underscores the demand for concrete solutions that are durable, cost-effective, and environmentally friendly. Alkali-activated materials (AAMs) present a promising alternative to traditional cements, contributing to more eco-friendly concrete production. In this research, twelve mixture compositions are explored, incorporating various combinations of precursors (slag, fly ash) and activators (sodium hydroxide and sodium silicate). Different alkali dosages and solution-to-binder ratios are also considered. The independent and combined effects of these parameters are observed on the development of main binder properties through specific experimental equipment. The first part focuses on characterizing the setting behavior of these novel binders. Continuous non-destructive tests, including ultrasonic pulse velocity (UPV) measurements and isothermal calorimetry tests, are combined with traditional tests such as slump flow, Vicat, and uniaxial compressive strength tests. For characterizing viscoelastic behavior post-setting, a novel technique involving repeated short-term creep tests is employed. This approach allows continuous monitoring, facilitating the characterization of early-age elastic stiffness and creep properties. To model short-term creep behavior, a power-law creep function is utilized. For long-term creep, a logarithmic creep function is applied. Furthermore, a logarithmic trend is observed in the development of specific creep over an extended duration of loading. An adapted version of the Model Code 2010 is employed to fit the experimental data, showing good agreement in modeling the specific creep of slag-based mortar samples., Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

Dans cette étude de recherche participative, nous avons développé un protocole de collecte de données pour comprendre les obstacles à la collaboration dans le secteur de l’architecture, de l’ingénierie et de la construction (AEC). Ce protocole se compose de trois étapes principales :la modélisation du processus de travail (workflow), l’évaluation de la qualité de la collaboration et le recensement des points aidants/bloquants survenus durant le projet. Il se base sur des méthodes visuelles pour faciliter la collecte et l’analyse des données lors d’entretiens. Pour évaluer l'adéquation de ce protocole à la réalité du terrain, nous avons organisé un workshop avec des praticien·ne·s du secteur AEC pour évaluer l'utilité, l'utilisabilité et l'acceptabilité de l'outil. Les résultats ont montré que le protocole était efficace pour identifier et comprendre les barrières et facilitateurs de la collaboration, mais des pistes d'amélioration ont également été identifiées pour optimiser l'outil dans un futur prototype., info:eu-repo/semantics/nonPublished

This study is aimed at evaluating the strength of stabilised soil collected from the Port of Norvik, Stockholm, Sweden, where 350,000 m 3 of clay had to be stabilized. The tests were performed in the laboratory of the Swedish Geotechnical Institute (SGI). The soil was stabilised by binder mixtures using Portland cement clinker (PCC) and lime and lime kiln dust (LKD). Accelerators (X-seed 100 BASF, PCC, LKD and salt) were added to the soil samples for quicker stabilization. The strength of the stabilised soil was assessed using resonance frequency measurements of seismic P-waves by an ICP accelerometer in order to estimate the shear strength of the soil and to evaluate the effects from the accelerators, binder ratios, and the curing temperature on the gains in stabilization and strength. Various proportions of the binders were tested, i.e. 50/50 cement/lime and 50/50 PCC/lime. The temperature was measured using a calorimeter in double experiments. The results showed that the accelerators improve the strength in the stabilized specimens and enhance the soil performance for engineering construction work., info:eu-repo/semantics/published

On the 18th of October 1908, the Belgian parliament voted in favour of the Belgian take-over of the Congo Free State from the Belgian king Léopold II, who had privately owned the Congolese territory but was forced to give up ‘his’ colony after the international outcry over the well-known Congo atrocities. With this vote, the Congolese territory officially switched hands, and the Belgian rule over Congo would remain in place until 1960. The advocates of the reprise had held up prospects of great gain by referring to the enormous mineral wealth of the colony, whereas the adversaries acutely remarked that the colony would only remain profitable if Belgium would continue on the same plundering elan than their internationally condemned king. The reality-check came quickly, when one of the strongest advocates, Jules Renkin, visited the Belgian Congo in his new role as the first minister of colonies. After a five-month journey through ‘his’ colony, he realized that for the material realization of the colonial ambitions to be economically and practically feasible, a cheap, locally produced building material would be of quintessential importance. However, as the colonial presence was justified through the paternalistic image of ‘helping’ the African inhabitants on their ‘path to modernity’, this colonial building material could not be one of the existing local building materials, as these were publicly denounced for being non-durable, insalubre [unhygienic] or even puant [stinking] — although in reality they remained in use for all sorts of colonial buildings throughout Belgian colonialism. Though seemingly a deadlock, the technocrats of the Belgian Congo remarkably quickly formulated an answer to this question: Concrete. Once a local cement plant would be established —which eventually only happened in 1921 after several failed attempts— concrete would be the deus-ex-machina that could resolve the apparent contradiction between the economic necessity to use local materials o, Doctorat en Art de bâtir et urbanisme (Polytechnique), info:eu-repo/semantics/nonPublished