On the competitive antagonism effect in combined chloride-sulfate attack: A numerical exploration

Abstract The resistance of concrete under chloride-sulfate attack dominates the durability of marine constructions. The binder played a more important role in chloride-sulfate resistance of concrete due to the dynamic hydration process. Incorporating supplementary cementitious materials (SCMs) was beneficial to the microstructure densification of cement paste, but the low hydraulic activities of SCMs resulted in the decrease of mechanical properties, activating activities of SCMs would raise the cracking risk of cement paste. On the basic of close packing theory, a gap-graded blended cement contained calcined hydrotalcite and metakaolin was adopted to prepare concrete with high resistance under chloride-sulfate attack in present study. The gap-graded blended cement concrete presented comparable strength with Portland cement concrete, even though only 25% clinker used in the blended cement. Because of the continuous hydration of alumina-rich SCMs and functional components, the secondary hydration products with high chloride binding capacity helped blocking ions ingress, resulting in the one-magnitude decrease of chloride diffusivity. At the early period of soaking duration in chloride-sulfate solution, the sulfate ions were beneficial to delaying the migration of chloride. And the cracks introduced by expansive products from sulfate attack would observably accelerate the release and continuous ingress of chloride at late period.

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Sulfate Attack Induced Dry–Wet Failure Modes and a Constitutive Model for Mortar Specimens with a Single Intermittent Fracture

International Journal of Geomechanics ◽

10.1061/(asce)gm.1943-5622.0001909 ◽

2021 ◽

Vol 21 (2) ◽

pp. 04020249

Author(s):

Tielin Han ◽

Zhihui Li ◽

Yunsheng Chen

Keyword(s):

Constitutive Model ◽

Failure Modes ◽

Sulfate Attack

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PHYSICOCHEMICAL ANALYSIS OF GROUND WATER AND SURFACE WATER IN KOTA REGION, RAJASTHAN, INDIA

FLORA AND FAUNA ◽

10.33451/florafauna.v24i1pp177-182 ◽

2018 ◽

Vol 24 (1) ◽

Author(s):

NITU SINGH ◽

FATIMA SULTANA

Keyword(s):

Surface Water ◽

Ground Water ◽

Growth And Development ◽

Physicochemical Parameters ◽

Total Dissolved Solids ◽

Physicochemical Analysis ◽

Total Hardness ◽

Developing Nation ◽

The Sustainable Development ◽

Chloride Sulfate

India is a developing nation and is dependent on its natural resources for growth and development. Water, being one of the vital natural resource, must be used judicially for the sustainable development. Present study focuses on the analysis of physicochemical parameters (pH, Turbidity, Alkalinity, Total Hardness, Total dissolved solids, Conductivity, Chloride, Sulfate, Fluoride contents) of ground water and surface water in Kota City (Rajasthan). The study shows the adverse impact of exploitation and urbanization on water resources of Kota City (Rajasthan). Some physicochemical parameters exceed the desirable limits as defined by WHO and Indian Standards in the selected sites. The level of pollution in ground water and surface water of Kota City is increasing due to urbanization.

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