China
Africa
Explore chapters and articles related to this topic
Foundations
Published in Derek Worthing, Nigel Dann, Roger Heath, of Houses, 2021
Derek Worthing, Nigel Dann, Roger Heath
In some sub-soils, there can be a problem with sulfate attack. Calcium, magnesium and sodium sulfates occur naturally in some clays and other sub-soils. They can, in wet conditions, attack the concrete (as well as below-ground cement mortars and some types of bricks) and cause severe degradation of the foundation. A high water table will exacerbate this problem. The sulphates dissolve in the groundwater and permeate any cement-based product, in this case the concrete foundation. This leads to an aggressive chemical reaction between the sulfates in solution and one of the chemicals in the cement. The resulting compound expands rapidly as it forms and this can crack the foundation concrete. If sulfate attack is a possibility, it is wise to use sulfate-resisting cement.
Literature Review
Published in Habeeb Lateef Muttashar, Sustainable Construction Materials, 2019
Generally, sulfate attacks occur when the cement reacts with sulfate-containing solutions, including natural or polluted ground water. In OPC, such attacks lead to a loss of mechanical strength, expansion, surface layer spalling, and finally breakdown (Žarnić et al., 2001). Meanwhile, inorganic alkaline polymers or GPCs such as alkali-activated metakaolin and FA show excellent tolerance to normal sulfate and sea water attacks due to having lower calcium phases. Bakharev (2005a) mentioned that a continuous cross-linked polymer structure of alumino-silicate is formed when NaOH is used as an alkali activator. Rangan (2008) pointed out that no damage occurs to the surface of FA-based GPCs when sodium silicate and NaOH are used as the alkaline activators. The specimen was immersed in sodium sulfate solution for about 1 year before conducting the test.
/ Durability, Serviceability and Fire
Published in L.H. Martin, J.A. Purkiss, Concrete Design to EN 1992, 2005
This occurs due to attack from free sulfates contained in groundwater or soil, and is therefore generally limited either to buried structures including foundations or structures in an aggressive environment where sulfates are naturally present, e.g. certain types of sewage, industrial effluent or chemical process plants. It is generally sufficient to combat sulfate attack by using Sulfate-Resisting Portland Cements (SRPC). In these cases, the requirement to ensure the existence of low permeability concrete in the structure is paramount as any ingress of sulfates should be prevented (Dunster and Crammond, 2003).
Influence of calcined medium grade clay on the properties of Portland cement pastes
Published in Geosystem Engineering, 2022
Nailia R. Rakhimova, Vladimir P. Morozov, Aleksey A. Eskin
Adoption of new SCMs necessitates comprehensive studies on the effect of them on the properties of fresh and hardened pastes, mortars and concretes. The important issue in the evaluation of new SCMs is an effect on durability of blended cements including various aggressive substances attack. One of the main durability problem of PC-based concretes is a resistance to sulfate attack when sulfates ingress into concrete elements from a sulfate-rich environment such as soil, seawater, decaying organic matter and industrial effluent. These external sulfate ions react with the components of cement paste, resulting in concrete deterioration over time. Sulfate attack in concrete can cause spalling, expansion, cracking, increased permeability and strength loss (Tian & Cohen, 2000). Large panel of structural elements including dams, concrete pavement, bridge piers, concrete piles, buried concrete foundations, highway or railway tunnels and floor slabs have faced substantial deterioration from sulfate attack around the world (Drimalas et al., 2011; Elahi et al., 2021; Lee et al., 2005; Ma et al., 2006; Mingyu et al., 2006; Rahman & Bassuoni, 2014; Sahu & Thaulow, 2004; Thomas et al., 2008).
Sulfate resistance of Portland-Limestone cement mortars cured at 20 °C and 60 °C
Published in Journal of Sustainable Cement-Based Materials, 2022
Aiwen Xu, Ji Lu, Jiangtao Xu, Duyou Lu, Zhongzi Xu
Concrete sulfate attack refers to the degradation caused by the reaction of external sulfate from the environment, e.g. ground water or soils, sea water, with the hydrates. It may lead to the precipitation of ettringite, gypsum (CaSO4·2H2O) and/or thaumasite (Ca6[Si(OH)6]2(SO4)2(CO3)2·24H2O), resulting in expansion, cracking and softening as well as strength loss of cement paste, which significantly shortens the service life of concrete structures [11–15].
Combination of immersion and semi-immersion tests to evaluate concretes manufactured with sulfate-resisting cements
Published in Journal of Sustainable Cement-Based Materials, 2019
E. Menéndez, R. García-Rovés, B. Aldea, S. Ruíz, V. Baroghel-Bouny
The sulfate attack in concrete structures basically consists of the chemical–physical reaction of the sulfate ions that interact with the hardened concrete. This type of attack can be external or internal depending on the situation of the sulfates in the system. If the sulfate ions are in the environment surrounding the structure itself and these penetrate into the concrete, it is considered external sulfate attack (ESA). If the sulfate is within the concrete structure, it is an internal sulfate attack (ISA).