Carbonation of concrete made with dredged marine sand and its effect on chloride binding

Li, Yongqiang; Cui, Hongzhi; Dong, Zhijun; Xing, Feng; Zhang, Haochuang; Lo, Tommy Y.

doi:10.1016/j.conbuildmat.2016.05.011

Cited by 100 publications

(31 citation statements)

References 33 publications

(43 reference statements)

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“…Moreover, one of the foremost issues [6,7] affecting the durability of concrete structures is steel corrosion caused by the carbonation of concrete [8][9][10], which also reduces the durability of reinforced concrete structures.…”

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confidence: 99%

Evaluation of the combined deterioration by freeze–thaw and carbonation of mortar incorporating BFS, limestone powder and calcium sulfate

Zhang

Kim

et al. 2017

Mater Struct

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The durability performance of cementitious material is traditionally based on assessing the effect of a single degradation process. However, this study investigates the coupled deterioration properties of mortar incorporating industrial solid wasteground granulated blast furnace slag (BFS) and different mineral admixtures, such as calcium sulfate (CS) and limestone powder (LSP). The combined deterioration properties caused by carbonation and frost damage in the mortar sample were experimentally investigated with respect to accelerated carbonation and freeze-thaw tests. Different degrees of deterioration, i.e. after subjected to 12, 30 and 60 freeze-thaw cycles, were induced in the freeze-thaw tests. The experimental investigation of single degradation revealed that the compressive strength, frost resistance and carbonation resistance decrease as the BFS replacement ratio increases by weight from 0 to 45%. The less amount of CH in the BFS cement leads to the carbonation progress more easily. Moreover, to achieve the same strength as ordinary Portland cement, 2 wt% CS and 4 wt% LSP in the BFS mortar are required. However, the data shows that incorporating LSP into the BFS mortar produces a lower frost resistance. The combined damage tests revealed that different deterioration degrees resulting from 12, 30 and 60 freeze-thaw cycles slightly decreased the carbonation resistance, which is related to the decrease in the inkbottle pore volume due to its water retention characteristics. Simultaneously, the pre-carbonation deterioration could effectively decrease the surface mass scaling of the freeze-thaw and the pore structure undergoes densification due to pre-carbonation.

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confidence: 99%

Evaluation of the combined deterioration by freeze–thaw and carbonation of mortar incorporating BFS, limestone powder and calcium sulfate

Zhang

Kim

et al. 2017

Mater Struct

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“…For a pH drop from 13.5 down to 12.5, the free chloride concentration increased about 1.5-fold ( Figure 5 ). The important new information compared to literature work in References [ 39 , 41 , 42 ], where full carbonation (thus pH ≈ 9) was reached, is that a large amount of released free chloride ions from bound chloride occurs between pH 13.5 and 12.5; thus, in a range of pore solution pH that is usually considered “alkaline”. This has implications for assessing the corrosion risk in reinforced concrete, which will be discussed in the next section.…”

Section: Discussionmentioning

confidence: 91%

“…No chloride ions entered into the mortar samples and this can be explained only by a release of initially bound chloride. Indeed, it is known that carbonation of the cement paste results in the release of bound chlorides due to the increase in the solubility of Friedel’s salt and to the decomposition of calcium-silicate-hydrate (C-S-H) gel, which may contain adsorbed chlorides [ 39 , 40 , 41 , 42 , 43 , 44 ]. Applying the novel method of simultaneous monitoring of both free chloride concentration and pH, this general mechanism that can be described in much more detail.…”

Section: Discussionmentioning

confidence: 99%

Development of a Novel Methodology to Assess the Corrosion Threshold in Concrete Based on Simultaneous Monitoring of pH and Free Chloride Concentration

Femenias

Angst

Moro

et al. 2018

Sensors

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Both the free chloride concentration and the pH of the concrete pore solution are highly relevant parameters that control corrosion of the reinforcing steel. In this paper, we present a method to continuously monitor these two parameters in-situ. The approach is based on a recently developed electrode system that consists of several different potentiometric sensors as well as a data interpretation procedure. Instrumented mortar specimens containing different amounts of admixed chlorides were exposed to accelerated carbonation, and changes in free chloride concentration and pH were monitored simultaneously over time. The results revealed the stepwise decrease in pH as well as corresponding increases in free chlorides, resulting from the release of bound chlorides. For a pH drop of about 1 unit (from pH 13.5 down to pH 12.5), the free chloride concentration increased up to 1.5-fold. We continuously quantified the ratio Cl−/OH− that increased steeply with time, and was found to exceed a critical corrosion threshold long before carbonation can be detected with traditional indicator spray testing, even at admixed chloride contents in the order of allowable limits. These results can strongly influence the decision-making in engineering practice and it is expected to significantly improve condition assessments of reinforced concrete structures.

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“…Liu. W et al [26] Chloride ion which is present in sea sand has some beneficial effect on the carbonation resistance of concrete. 26…”

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confidence: 99%

Application of Seawater and Sea Sand to Develop Geopolymer Composites

Luhar¹,

Luhar²

2020

IJRTE

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Worldwide, concrete is predominantly used as a versatile building material with its highest consumption on the earth. Nevertheless, its exigency accelerates day by day exhausting restricted natural resources in its manufacturing. Consequently, in order to prevent the degradation of these natural confined aggregates resources, it’s highly essential to employ other alternative profuse materials in their place. On the one hand, the sea Sand is existing in huge quantity below seas and oceans while on the other hand, restricted river Sand resources are being quarried haphazardly and hence reaching to their end. What’s more, to flashlights on, the production of every ton of cement contributes to the emission of an almost equal quantity of CO2 with high energy consumption. Also, it is worth mentioning that freshwater resources are in the limited quantity and, therefore, mankind is not getting sufficient fresh water even to drink in some corners of the world. In present experimental investigations, all the above burning dilemmas are kept in mind and hence, the sea Sand is used as an alternative to river Sand whereas sea water is used instead of distilled water for laboratory investigations on the properties of Geopolymer concrete and mortar in the total absence of Ordinary Portland Cement. The results demonstrated that the sea sand and seawater have no doubt affected the strength of Geopolymer concrete and mortar but just insignificantly.

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Carbonation of concrete made with dredged marine sand and its effect on chloride binding

Cited by 100 publications

References 33 publications

Evaluation of the combined deterioration by freeze–thaw and carbonation of mortar incorporating BFS, limestone powder and calcium sulfate

Evaluation of the combined deterioration by freeze–thaw and carbonation of mortar incorporating BFS, limestone powder and calcium sulfate

Development of a Novel Methodology to Assess the Corrosion Threshold in Concrete Based on Simultaneous Monitoring of pH and Free Chloride Concentration

Application of Seawater and Sea Sand to Develop Geopolymer Composites

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