![]() ![]() The results show that the compressive strength values of geopolymer G2 (22.9, 27.6, 32.6, 36 and 39.7 MPa) are higher than that of G1 (17.7, 19.1, 21.2, 29.9 and 32.8 MPa) at 7, 14, 21, 28 and 56 days respectively. The mechanical testing, environmental scanning electron microscopy, mercury intrusion porosimetry, X-ray diffractometry, infrared spectroscopy, amount of binders and thermogravimetric analysis are investigated to study the properties of the geopolymer binders. The IR spectra of S1, S2 using ATR and KBr methods show the presence of SiQ0, SiQ1, SiQ2 units, and S1 contained also SiQ3 and SiQ4 units. ![]() Metakaolin-based geopolymer binders (G1, G2) were obtained using freshly prepared NWG with a mass ratio NWG/MK = 0.83. Rice husk and waste glass from sources in Cameroon were used for producing sodium waterglass (NWG) solution denoted S1 and S2 respectively as alternative activators to prepare metakaolin-based geopolymer binder. More efficient use of Portland cement clinker in mortars and concretes.However, other emerging technologies could also play an important role in emissions mitigation in the longer term, and thus merit further investigation. Increased use of low-CO2 supplements (SCMs) as partial replacements for Portland cement clinker.2. Two product-based approaches can deliver substantial additional reductions in their global CO2 emissions, reducing the need for costly investment in carbon capture and storage (CCS) over the next 20–30 years: 1. We believe that Portland-based cement approaches will dominate in the near future due to economies of scale, levels of process optimisation, availability of raw materials and market confidence. The main conclusions of an analysis of low-CO2, eco-efficient cement-based materials, carried out by a multi-stakeholder working group initiated by the United Nations Environment Program Sustainable Building and Climate Initiative (UNEP-SBCI) are presented, based on the white papers published in this special issue. Project targets scrivener windows 8.1 Activator#In addition, the study evidenced that the use of waste glass-based activator allows a significant reduction in every environmental category when compared to the use of commercially available chemicals. Results show that the adoption of alkali-activated concretes instead of OPC concrete allows a significant reduction in environmental categories of global warming (averagely 64% reduction for AABC and 70% for AABR), acidification potential (averagely 23% for AABC and 35% for AABR), and terrestrial eutrophication (averagely 53% for AABC and 60% for AABR). ![]() The effects produced by the variations of some key parameters (impact allocation of precursors, energy mix, amount of activator in the concrete, distance of procurement of raw materials) over the total impact of the AABR are also investigated. Through a Life Cycle Assessment (LCA), the investigation aims to compare the AABR to Ordinary Portland Cement (OPC) concrete and alkali-activated concrete produced with commercially available chemicals (AABC). This paper investigates concrete belonging to strength classes 35, 50 and 70 MPa and produced with a silicate activator derived from waste glass (AABR). Alkali-activated concretes have been investigated in literature as a possible alternative, but the sustainability still appears reduced by the high embodied energy of chemicals typically used for the activation step. ![]() Obtained results demonstrated the technical feasibility of manufacturing building blocks with alkali-activated concrete, and highlighted the challenges for a viable and sustainable application of this technology.Ĭoncrete is responsible for a significant share of global GHG emissions, which can be mainly ascribed to the production of clinker. Project targets scrivener windows 8.1 full size#Laboratory investigations on binder development, concrete mix proportioning, and building block sample production, as well as full size factory trials with industrial equipment, were carried out for assessing the potential and the challenges of this technology. This paper discusses the experience gathered in the manufacture of building blocks using alkali-activated concrete produced from waste streams such as fly ash, slag, or cement kiln dust. A number of possible solutions are currently offered by the research, which has been investigating the recycling of waste/by-products into sustainable building materials during the last decades. The need for decent and affordable houses is an urgent problem for many developing countries, whereas the concerns about the carbon emissions related to the manufacture of Portland cement are growing worldwide. Several global challenges identified by the UN Sustainable Development Goals are either directly or indirectly linked to the construction sector. ![]()
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