Durability Assessment of Blended Concrete by Air Permeability

Katpady, Dhruva Narayana; Hazehara, Hirotaka; Soeda, Masashi; Kubôta, Takashi; Murakami, Satoshi

doi:10.1186/s40069-018-0260-9

Cited by 17 publications

(9 citation statements)

References 35 publications

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“…As can be seen from Figure 10, the concrete sample is mainly composed of 3CaO•SiO 2 , 2CaO•SiO 2 , CaCO 3 , Ca(OH) 2 , and C-S-H. As can be seen from Table 8, the carbon element invades the insides of the test specimens and a chemical reaction occurs as per the above equation (1) to (4). The 3CaO•SiO 2 , 2CaO•SiO 2 , and Ca(OH) 2 are largely consumed and a large amount of CaCO 3 is generated.…”

Section: Xrd Analysismentioning

confidence: 97%

“…The passivation film formed on the surface of the steel in a high alkalinity environment is destroyed, which causes the chloride ions adhering to the concrete to be converted into free chloride ions. In severe cases, concrete shrinkage deformation occurs which in-turn affects the structural volume stability [1][2][3][4][5]. Carbonation is an important factor that causes durability problems in concrete structures and reducing service life.…”

Section: Introductionmentioning

confidence: 99%

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Carbonation Resistance Performance and Micro-Structure Analysis of Glazed Hollow Bead Insulation Concrete

2019

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In this paper, the carbonation depths of glazed hollow bead insulation concrete (GHBC) and normal concrete (NC) at different carbonation ages are tested. The microstructure of GHBC and NC before and after carbonation were observed and compared by mercury intrusion porosimetry (MIP), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). The results showed that NC had better carbonation resistance than GHBC, and GHBC had a carbonation depth of 1.61 times than that of NC at 28 days accelerated carbonation experiment. The microstructural analysis showed that with the decrease of porosity of the samples, the carbon content and CaCO3 content increased after carbonation. The porosity of NC decreased from 14.36% to 13.53%, the carbon content increased from 4.42% to 5.94%, and the CaCO3 content increased from 18.5% to 56.0%. The porosity of GHBC decreased from 22.94% to 20.71%, the carbon content increased from 4.97% to 5.31%, and the CaCO3 content increased from 70.0% to 82.0%. The above results showed that carbon reacts with hydration products 3CaO·SiO2, 2CaO·SiO2, and Ca(OH)2 to produce a large amount of CaCO3 which causes a large amount of pores to be filled and refined hence the porosity and pore size were reduced leading to increase in the compactness of the material. From the results obtained, the carbonation depth prediction formula of glazed hollow bead insulation concrete was developed, and carbonation life was predicted.

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Section: Xrd Analysismentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Carbonation Resistance Performance and Micro-Structure Analysis of Glazed Hollow Bead Insulation Concrete

2019

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“…Transport laws based on power laws have been known for a long time and have been applied to the air permeability of concrete in [15]. A high correlation in concrete has also been found for coefficient of air permeability, carbonation depth and chloride ion diffusion in [17]. However, the type of cement and the usage of supplementary cementitious materials have a strong influence on the diffusion of chloride ions in concrete and may shift the relations given in Fig 3.…”

Section: Concrete Durability Indicatorsmentioning

confidence: 99%

Mix-Design and Control of Exposure Class of Durable Concrete

Paulini

2019

MATEC Web Conf.

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Durability requirements for concrete are determined by climatic, chemical and mechanical effects, depending on the climatic location and intended use of structural parts. The European standard EN 206-1 defines different types of exposure classes and specifies requirements for concrete, such as type and minimum quantity of cement, maximum w/c ratio, minimum compressive strength or minimum entrained air pore content. Additional characteristics required for a higher workability often lead to contradictory situations in practice and cannot be satisfactorily resolved by varying the mix design of the concrete. Based on a real life scenario where a C35/45 XD3 concrete had been used in the construction of a multi-storey car park, which presented serious cracking after only a short service time, this paper proposes a number of methods designed to assess the quality and durability of concrete. The proof of exposure classes at the hardened building concrete is not regulated in existing national standards. Therefore, in many court disputes it is difficult to prove the quality of the hardened concrete because of lacking regulations. However, it is possible to verify the w/c-ratio using the capillary porosity. The basic relationships between cement content, w/c-ratio and capillary porosity are derived and discussed. Higher proportions of cement, which are necessary to achieve a better workability or higher strength, result in a reduced modulus of elasticity and increased shrinkage as well as a higher risk of cracking. The associated increase of capillary pore volume and of permeability reduces the service life of concrete. The determination of performance-based concrete properties such as permeability, chloride migration or electrical conductivity further complements the assessment of concrete durability. These properties can be used for estimating the resistance of the capillary pore structure to specific damage mechanisms.

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“…ere have been many studies on the durability evaluation of concrete. Katpady et al [9] measured the air permeability and its index to evaluate the durability of concrete. Qin et al [10] evaluated the durability of concrete specimens with durability values and predicted the changing pattern of concrete durability values.…”

Section: Introductionmentioning

confidence: 99%

Durability Evaluation of Concrete in Cold and Arid Regions Based on Grey Relational Theory

Gong

Liang

Zhang

et al. 2022

Advances in Civil Engineering

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Aiming at the outstanding problem of concrete durability in cold and arid regions, the Datonghe-Qingwangchuan Diversion Project in Gansu Province, China, was used as a typical research area, and erosion products were determined by field sampling and laboratory XRD analysis. Three durability evaluation indices, namely, the mass loss rate, relative dynamic elastic modulus (RDEM), and compressive strength loss rate, were measured via indoor accelerated testing. Based on grey relational theory, a concrete durability evaluation model was constructed. The critical failure values of the three evaluation indices were introduced as a set of data to optimize the model and determine the grey relational degree of each group of concrete specimens under different working conditions. The results show that using the test results and the optimized grey relational analysis evaluation model, the concrete specimens mixed with an air-entraining agent have strong resistance to composite erosion. The durability of concrete specimens with an air-entraining agent content of 0.016% and fly ash content of 15% is better, and a high content (30%) of fly ash accelerates the damage of concrete specimens. The model calculations are consistent with the test results. This method can solve the problem of the durability of concrete specimens in the whole test cycle not being fully evaluated. The results of the study provide useful references for concrete mix proportion optimization and durability evaluation problems.

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Durability Assessment of Blended Concrete by Air Permeability

Cited by 17 publications

References 35 publications

Carbonation Resistance Performance and Micro-Structure Analysis of Glazed Hollow Bead Insulation Concrete

Carbonation Resistance Performance and Micro-Structure Analysis of Glazed Hollow Bead Insulation Concrete

Mix-Design and Control of Exposure Class of Durable Concrete

Durability Evaluation of Concrete in Cold and Arid Regions Based on Grey Relational Theory

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