The effect of the composition and production process of concrete on the 222Rn exhalation rate

Jong, Peter de; Dijk, W. van; Hulst, J.G.A. van; Heijningen, R.J.J. van

doi:10.1016/s0160-4120(96)00120-1

“…De Jong [8] reported that an addition of fly ash in general reduces the general pore size, which is consistent with findings by Zhuqing & Guang [22], where the relative critical pore size of cement paste blended with fly ash is smaller than for reference cement paste after 90 days of curing and onwards. Setina et al [23] reported similar conclusions where the use of micro silica as a SCM reduced the total pore volume and also an overall smaller pore size compared to a reference concrete.…”

Section: Discussionsupporting

confidence: 89%

“…Accordingly, an additive, that repels water droplets (hinders free transport -clogging the pores) from the concrete surface, may also have a direct effect of the permeability or diffusion rate within the concrete [8].…”

Section: Ionizing Radiation and Healthmentioning

confidence: 99%

Reduction of Radon Gas in Concrete Using Admixtures and Additives

Döse

¹

,

Silfwerbrand

²

2018

Nordic Concrete Research

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The second largest cause of lung cancer is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI) has examined three concrete recipes where only an additive as well as fly ash were added as single constituents to a reference recipe and compared to a reference concrete. The inputs of an additive as well as a supplementary cementitious material (fly ash) were made as a mean to investigate their potential influence on the radon exhalation rates of the concrete. Measurements were performed with an ATMOS 33 ionizing pulsation chamber for at least five different occasions for each recipe during a 22 month period. The results indicate a reduction of the exhalation rate by approximately 30-35 % for each altered recipe. This means roughly 1.5-2 mSv per year decrease in effective dose to a human using an additive or a supplementary cementitious material such as fly ash in relation to the investigated standard concrete.

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“…It was noted that building materials of geometrical differences could associate with different radon emanation rates. In comparison with other common building materials, the radon emanation rates of the tested partition materials samples were slower (Al‐Jarallah, 2001; Al‐Jarallaha et al , 2001; Carrera et al , 1997; Chao et al , 1997; Gao et al , 2002; Jong et al , 1996; Keller et al , 2001; Stoulos et al , 2003; Yeung, 1996; Yu, 1994; Yu et al , 1995). In contrast, the radon emanation rates of a concrete block and two typical granite slabs (granite‐I and granite‐II) they were found to be 8.7, 13.4 and 0.58 Bq m −2 hr −1 respectively in a small chamber (Chao et al , 1997).…”

Section: Resultsmentioning

confidence: 84%

“…In an indoor environment, building construction materials are a major emission source of radon. Therefore, selection of the building materials is one of the primary concerns regarding radon level control for the indoor environment (Al‐Jarallah, 2001; Al‐Jarallaha et al , 2001; Carrera et al , 1997; Chao et al , 1997; Gao et al , 2002; Jong et al , 1996; Keller et al , 2001; Stoulos et al , 2003; Yeung, 1996; Yu, 1994; Yu et al , 1995).…”

Section: Introductionmentioning

confidence: 99%

Radon emanation rates of common partition materials in Hong Kong

Mui

¹

,

Wong

²

,

Au‐Yeung

³

2005

Facilities

1

0

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PurposeTo determine the radon emanation rates of common partition materials in Hong Kong.Design/methodology/approachAn initial slope of radon gas growth against time and a mass balance analysis can be used to quantify the magnitude of these rates from different types of partition materials. In particular, the radon‐222 emanations from boards of calcium silicate, gypsum and lightweight concrete were measured experimentally in a small impervious radon chamber.FindingsThe radon‐222 emanations from boards of calcium silicate, gypsum and lightweight concrete were measured experimentally in a small impervious radon chamber, and expressed as becquerels per square meter per hour of air (Bq m−2 hr−1). The rates found were 2.43, 0.22 and 0.46 Bq m−2 hr(1 respectively. Comparing with the emanation rate and the quantities of radon emitting construction materials in Hong Kong, these three partition materials have a low radon emitting level.Research limitations/implicationsThe model parameters used in the study were not exhaustive and were determined from samples of materials used in Hong Kong.Practical implicationsA useful source of reference for determining the radon emanation rates of common partition materials used in building developments. The results can be used to identify the exposure risk of radon in buildings.Originality/valueThis paper proposes a mathematical model of radon emanation rates of common partition materials. The model offers practical helps to professionals planning, designing and managing the selection of building materials in buildings.

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“…For fly ash a reduction of 30-35 % could be shown compared to the reference concrete. [8] Reported that an addition of fly ash in general reduces the general pore size. [9,10] reported similar conclusions where the use of fly ash and micro silica as a SCM reduced the total pore volume and also an overall smaller pore size compared to a reference concrete.…”

Section: Discussionmentioning

confidence: 99%

Supplementary Cementitious Materials and Additives – Effective Measures to Hinder Radon in Concrete

2018

jae

1

0

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The second largest cause of lung cancer is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI) has examined ten different concrete recipes containing an additive or Supplementary Cementious Material (SCM), such as fly ash, slag or silica and combinations thereof. The SCM´s were added in small to moderate portions and substituted the reference Portland cement (OPC). The inputs of an additive as well as a supplementary cementitious material were made as a mean to investigate their potential influence on the radon exhalation rates of the concrete as well as the radon gas diffusion length (L) that could be expected from the different recipes. Measurements were performed with an ATMOS 33 ionizing pulsation chamber. The results indicate a reduction of the exhalation rate by approximately 10-55 % depending on recipe at an RH of 75 %. The diffusion coefficients, corrected for background subtraction vary in the interval 1.1 x 10-10 – 7.6 x 10-12 m/s2. The diffusion lengths vary between 2 and 9 mm. In the case where the largest reduction of the exhalation rate is achieved, this roughly correspond to >2 mSv per year decrease in effective dose to a human. Consequently, using an additive or a SCM, as part of the mix, would be an option to effectively lower the radon gas exhalation in their initial stage of production. Secondly, the use of additives and SCM´s will contribute to a lower environmental impact (CO2).

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The effect of the composition and production process of concrete on the 222Rn exhalation rate

Cited by 16 publications

References 10 publications

Reduction of Radon Gas in Concrete Using Admixtures and Additives

Reduction of Radon Gas in Concrete Using Admixtures and Additives

Radon emanation rates of common partition materials in Hong Kong

Supplementary Cementitious Materials and Additives – Effective Measures to Hinder Radon in Concrete

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