WebTwo types of alkali-activated material (AAM) concretes were exposed to various sulphate bearing-solutions for over two years. Physical changes to the concrete specimen and chemical changes in the exposure liquid were studied in an attempt to understand how sulphate attack occurs in such binders and the role the mix variables play in offering … WebThe side view of the samples illustrates that external sulfate attack is a process which progresses into the samples layer by layer, as further described in the following sections. With the mortar samples there is a long delay before seeing any manifestations of sulfate attack even though the degradation of the bottom surface is quite profound.
An ACI Technical Publication - American Concrete Institute
External sulfate attack (ESA) is the process of concrete degradation involving expansive reactions between sulfate ions coming from an external source and the phases in the hardened matrices [1, 2]. Degradation mechanisms vary depending on several factors, such as the type of binder used, the formulation of … See more Figure 1 shows the compressive strength (fc) results expressed in MPa and obtained for each concrete at 28 days of curing. The Standard NF EN 206/CN (French national addition to EN 206) sets C35/45Footnote 1 as … See more Figure 2a, b show the longitudinal expansions measured for concretes cured for 28 and 90 days before attack, respectively. Expansion is plotted versus time in days and the … See more Microstructural/mineralogical analyses and thermodynamic calculations results are presented by concrete category: Portland cement concretes, … See more WebJan 14, 2024 · External sulfate attack is the most common type and typically occurs where water containing dissolved sulfate penetrates the concrete. The composition and microstructure of concrete will... male canning
Types of Sulphate Attack in Concrete- Influences and …
WebSep 7, 2024 · In the early sulfate attack period, the pore structure of the concrete was filled with sulfate attack products (e.g., ettringite and gypsum), and its mass and strength increased. ... “Multi-criteria analysis of the mechanism of degradation of Portland cement based mortars exposed to external sulphate attack,” Cement and Concrete Research ... WebMar 1, 2024 · External sulphate attack (ESA) is a complex degradation process that can compromise the long-term durability of cement-based materials in contact with … Webunder external sulfate attack. A comparison between numerical results and experimental data is provided to validate the proposed models. 2.0 DESCRIPTION OF THE CHEMO-TRANSPORT MODEL 2.1 Mechanism of sulfate attack When sulfate ions penetrate into a cement-based material, a series of reactions take place between the male captum bene retentum significato