Ultra-High Performance Concrete (UHPC) exhibits high autogenous shrinkage (AS) which significantly increases the risk of early age cracking. To predict risks cracking environmentally friendly CEM III-based UHPC, a numerical model originally developed for crack assessment ordinary concrete, has been further and applied on demonstration wall with cracking, cast non-deforming slab. The design was ...

Class F Fly ash-based geopolymers are prone to various high-temperature phenomena, such as cracking, spalling, and thermal shrinkage. Here we study the effect of enriching fly ash with synthetic sodalite phase in order enhance properties formed geopolymer. The morphological changes, compositional alterations porosity, gel behaviour, on deformation material after exposure up 1000 °C investigated...

This study investigates the effect of inclusion size on drying shrinkage cracking in cementitious materials. A series laboratory desiccation tests concrete with different inclusions are conducted. Nondestructive X-ray micro-tomography images were used to reconstruct drying-induced cracks samples tests. To better understand mechanism cracking, a fully coupled hydro-mechanical bond-based Peridyna...

Sand-®lled cracks from the Lower Fine-grained Quartzite of Dalradian (late Proterozoic) age on the Island of Islay, western Scotland, may be divided into two main types, both of which form orthogonal and non-orthogonal closed patterns on bedding surfaces. Type 1 cracks are short and lenticular in cross-section, contain sand which had been injected downwards, and are found on the bottoms of cros...

Plastic cracking of concrete such as plastic settlement and plastic shrinkage cracking is directly related to the bleeding of concrete, which is a natural time-dependent process in a fresh concrete mix. A portion of the mixing water together with very fine materials finds its way to the surface of the concrete during this process. The rapid rate of initial bleeding slows down with the elapsed t...

This study explored the reactive processes of atmospheric carbonation and consequences with respect to cementitious materials. Two model pastes were used: hydrated C3S (including C-S-H portlandite) a paste prepared by hydrating blend nanosilica only). The two carbonated under accelerated conditions in laboratory. resulting mineralogical assemblage was examined using X-ray diffraction, thermogra...

The Minnesota Department of Transportation (Mn/DOT) Precast Slab Span System was initially designed by Mn/DOT with input from University of Minnesota researchers and local fabricators. The bridge system consisted of a series of precast, prestressed concrete inverted tee bridge elements which also served as stay-in-place formwork for the cast-in-place portion of the deck placed in the field. One...

The value of gem opals is compromised by their potential susceptibility to “crazing”, a phenomenon observed either in the form whitening or cracking. To understand latter, 26 opal samples were investigated and separated into 2 groups based on handling: “water-stored” samples, which are stored water after extraction, “air-stored” air for more than year. induce cracking, thermally treated staged ...