What century is 2024? the 21st century 2024 (MMXXIV) will be a leap year starting on Monday of the Gregorian calendar, the 2024th year of the Common Era (CE) and Anno Domini (AD) designations, the 24th year of the 3rd millennium and the 21st century, and the 5th year of the 2020s decade. Centuries: 20th century. 21st century.21st Century Years of the Gregorian calendar, which is currently in use, are counted from AD 1. Thus, the 1st century comprised the years AD 1 through AD 100. The second century started with AD 101 and continued through AD 200. By extrapolation, the 20th century comprises the years AD 1901-2000. Therefore, the 21st century will begin with 1 January 2001 and continue through 31 December 2100. Third Millennium Similarly, the 1st millennium comprised the years AD 1-1000. The 2nd millennium comprises the years AD 1001-2000. The 3rd millennium will begin with AD 2001 and continue through AD 3000. The conference will aim to present and discuss the recent advances in materials and structures research to meet the great challenges of the 21th century and beyond: enable sustainable, safe and durable construction (new and existing buildings and strategic infrastructures), promote the circular construction / economy; improve the energy efficiency of construction, favour the quality and comfort of building (indoor air quality and comfort). All these topics will be considered from the material’s perspective, but also from the structure’s perspective. A special focus will be put on the worldwide practices and rationale to meet these goals. The conference will cover all the topics in the scope of RILEM scientific activities, and will include: > At the level of the building materials: Cementitious materials (conventional and low-CO2 binders, alkali-activated materials and geopolymers, new binders (sulfur, magnesium, etc.)), Bricks, stone, masonry, mortars, grouts Bio-based materials, earth construction (special session organised) Bituminous materials (special session organised) Wood and timber structures > At the level of the civil engineering structures: Buildings: Quality of indoor air, comfort, hygrothermal behaviour of building materials Strategic infrastructures in their environments For any of these topics, scientific contributions investigating the time and service related properties: early age and setting, service properties, durability, safety, environmental impact, recyclability, will be particularly welcome A special focus will be done on the special practices according to the world regions.