Experimental and numerical study on cement paste degradation under external sulfate attack

External sulfate attack is one of the situations that may cause gradual but severe damage in cementitious materials, which may lead to cracking, increased permeability and strength loss. In this paper, thin-walled hollow cement paste cylinders with a wall thickness of 2.5mm were made considering the slow penetration process of sulfate ions under...

The city as a campus

From an analysis of the higher education system in Bogotà, it came out an isolation and social closing of university campuses in the city.<br/>It follows that high knowledge becomes elitist and inaccessible, and that the city and the university are losing their relation.<br/><br/>The design consists in opening a new democratic dialogue between...

Expansion and degradation of cement paste in sodium sulfate solutions

External sulfate attack is a progressive degradation process that may cause expansion, cracking, loss of binder cohesion and increased permeability in cementitious materials. Crystallization pressure theory has often been referred to as the most likely mechanism. However, thus far the stress causing the expansion has not been quantified. In...

Cement paste degradation under external sulfate attack: An experimental and numerical research

Chemical degradation of cementitious materials is a serious threat to the durability and performance of concrete structures. External sulfate attack is one of the situations that may cause gradual but severe damage. Sulfate ions present in seawater, rivers, groundwater and industrial effluent can penetrate into the hardened concrete, and react...

Experimental investigation of ASR-affected concrete – The influence of uniaxial loading on the evolution of mechanical properties, expansion and damage indices

The alkali silica reaction (ASR) in concrete causes internal localized swelling and micro cracking, which result in expansion and correlated deterioration of the concrete material. The stress state of the concrete is known to affect expansion due to ASR, with an anisotropic stress state giving rise to anisotropic expansion. Similarly, the...

Influence of external environment on early-age expansion characteristics of calcium sulfoaluminate cement-based binders

Calcium sulfoaluminate (CSA) cements are widely being promoted as alternative low CO2 binders. CSA cements can also be expansive and designed to be shrinkage-compensating. The main phase of CSA cement is ye’elimite, which hydrates in the presence of calcium sulfate to form ettringite as the main hydration product. The availability of calcium...

Woningen in de derde en vierde uitleg van Amsterdam: Het verband tussen de woningen en de percelen, en de uitleggen zelf

The city of Amsterdam was steadily expanding and Jacob van Deventer's minute map from 1560, shows that people were already settling outside the ramparts and along the Amstel River. Something had to be done. The city council decided to expand the city several times. This report focuses on amsterdam's third and fourth extensions and how the chosen...