Sulfate resistance of portland-limestone cement concrete systems: Linking laboratory and field performances

Performance of Concrete Pavement Incorporating Portland Limestone Cement in Cold Weather

“…There was indication of continual hydration development of both matrices, with comparable primary ettringite and portlandite peaks at 50 to 120 • C and 400 to 450 • C, respectively (e.g., Figure 7). This conformed to the microscopy analysis (e.g., Figure 8), since PLC and GU matrices attained comparable and homogenous morphologies without visible signs of micro-cracking or infilling of air voids with complex assemblages typically resulting from chemical attack of concrete [13][14][15]. Furthermore, EDX showed the presence of minor chloride traces in the systems, which substantiated the sufficient degree of hydration and high resistance of the mixtures used to the ingress of chloride ions from the applied de-icers, especially in the case of PLC-produced concrete.…”

“…Limestone powder has attracted many researchers due to its wide availability and low cost. To properly optimize the use of LS, researchers have conducted a lot of research on the action mechanisms of limestone of different sizes, dosages, dissolution rates and polymorphology on different concrete properties [2,3,[10][11][12][13][14][15][16][17]. While limestone powder is considered a partially inert filler, it can positively affect the development of concrete microstructures owing to its fine nature (1000 to 6000 m 2 /kg) [10], which optimizes particle size distribution and improves particle packing of produced cement [10].…”

“…In addition, fine limestone particles (0.7 to 15 µm) [10] were reported to act as nucleation sites for hydration products to precipitate on, and they engage with aluminate phases to form carboalumiante compounds, thus improving microstructural development of hardened paste compared to that produced from hydration of ordinary cement [3,10]. Several laboratory studies have highlighted the benefits of PLC with respect to improving concrete pumpability/workability [3] and increasing its resistance to ingress of fluids, acids, carbonation and chloride-based salts [11][12][13][14][15][16][17]. In addition, the use of PLC in concrete improved its resistance to freezing and thawing cycles with/without de-icers [13,14,16].…”

Research on Resistance to Sulfate and Chloride of Reinforced Metakaolin-Based Geopolymers

“…Aggressive environmental conditions depend on the concentration and mobility of the sulfate ions, the type of cations it has (Ca 2+ , Mg 2+ , Na + , and K + ), and pH (Komnitsas et al, 2013;Ren et al, 2017). As a result of the sulfate attack, compounds such as calcium hydroxide (CH), monosulfate (AFm), and tricalcium aluminate (C3A) react with sulfate ions, causing expansive salt crystals such as gypsum and ettringite (ettringite is more harmful than gypsum) to form in the hardened cement paste (Tiburzi et al, 2020;Nosouhian et al, 2019). Consequently, the expansion and cracking caused by the sulfate effect, adversely affect the structural integrity of the concrete.…”