Siliceous Concrete Research Articles

Evaluation of Protective Effectiveness and Microstructure of Silicate Concrete Sealer

This study employed Taguchi method to identify key factors influencing the protection provided by the surface treatment of reinforced concrete structures. We evaluated the protective characteristics of silicate concrete sealer (SCS) as well as its underlying mechanisms. An L12 (27) orthogonal array was produced using seven control factors and two levels to obtain the necessary data from only twelve experiments. Tests were performed to evaluate compressive strength, water absorption, and permeability. The major factors influencing the effectiveness of SCS included the water-binder ratio of the substrate, cumulative curing time of the sealer, content of pozzolanic material, and type of sealer materials. XRD analysis and SEM observation revealed the composition and efficacy of SCS in protecting concrete. The SCS reacted chemically with the cement hydration product Ca (OH)2 and filled the pore structure with C-S-H gel, which succeeded in greatly improving the mechanical properties of the concrete.

Exceptionally preserved crustaceans from the Oxfordian of eastern France (Terrain à Chailles Formation, Haute-Saône)

The Oxfordian fauna from the Terrain à Chailles Formation, eastern France (Haute-Saône, Franche-Comté) is remarkable for its exceptionally preserved crustaceans found in siliceous concretions locally named “chailles”. The crustacean fauna includes 9 different species assigned to the Glypheidae, the Erymidae, the Eryonidae and the Axiidae. Glypheid and erymid lobsters are the most diversified groups with four and three different species respectively. Re-examination of numerous new specimens allows to a more modern and more complete characterization of Glyphea regleyana (Desmarest, 1822), Glyphea muensteri von Meyer, 1840 and Eryma ventrosa (von Meyer, 1835). New detailed anatomic descriptions of these species highlight the presence of marked sexual dimorphism in G. regleyana and probably in E. ventrosa. They reveal processes of autotomy and phenomena of ecdysis in G. regleyana, E. ventrosa and G. muensteri. Quantitative analyses based on 424 nodules show three dominant species: 1) Glyphea regleyana (50.5% of nodules); 2) Eryma ventrosa (24.8%); and 3) Glyphea muensteri (16.5%). Convergent lines of evidence from depositional environment, comparisons with others Jurassic crustaceans and modern analogues indicate that the crustacean fauna from the Terrain à Chailles Formation probably inhabited a moderately deep water setting most probably about 100–150 m (lower circalittoral zone) where light intensity was even sensitive. These crustaceans constitute a very original assemblage intermediary between the communities from the shallow carbonate platforms (e.g., Solnhofen) and those from the bathyal zone (e.g., La Voulte). This new set of data sheds new light on the colonization of the distal platforms by crustacean communities in the Mesozoic.

Guzhangian (mid Cambrian) trilobites from siliceous concretions of the Valtorres Formation, Iberian Chains, NE Spain

AbstractIn the carbonate-siliciclastic strata of West Gondwana (e.g. in the Montagne Noire, France), the aftermath of the mid Languedocian (mid Cambrian) regression is characterized by a late Languedocian major turnover of trilobite families and a Furongian–early Tremadocian radiation related to the stepwise immigration of trilobite invaders from East Gondwana under persistent transgressive conditions. The scarcity of upper Languedocian fossil accumulations in clayey substrates has inspired the sampling of the palaeogeographically most distal parts of the Iberian Chains (Spain), where diagenetic dissolution of ubiquitous hexactinellid sponge spicules has favoured the formation of siliceous concretions. These have yielded the trilobitesPeronopsiscf.insignis,Oidalagnostus trispinifer,Proampyx difformis(=Proampyx aculeatus),Bailiaspis?glabrata(=Holocephalina agrauloides, by ontogeny),Holasaphuscf.centropygeand a paradoxidid gen. et sp. indet. Despite preservation and sampling biases, the identification of this taphonomic window in offshore clayey substrates of West Gondwana allows the recognition of a strong biogeographical link with Baltica, and the correlation of the global Guzhangian Stage and theSolenopleura?brachymetopaZone of Scandinavia with part of the Mediterranean upper Languedocian Substage.

PRESERVATION OF GIANT ANOMALOCARIDIDS IN SILICA-CHLORITE CONCRETIONS FROM THE EARLY ORDOVICIAN OF MOROCCO

The recently discovered Fezouata Biota, from the Early Ordovician (late Tremadocian to late Floian) of Morocco, preserves a diverse soft-bodied fauna. While preservation is mostly of Burgess Shale-type, giant anomalocaridids also occur in siliceous concretions. Petrographic and geochemical analyses of these concretions reveal their growth history and the circumstances that led to the fossilization of nonbiomineralized anatomy within them. The large ( .1 m) concretions are homogeneous in composition and geochemical characteristics, suggesting rapid, pervasive growth of mineral frameworks during decay of the large animals at, or near, the sediment-water interface. Concretions are comprised of ultrafine-grained (2–20 mm) authigenic quartz, Fe chlorite, and calcite, a composition unlike other described marine concretions. Abundant pyrite, now represented by oxide pseudomorphs, grew adjacent to the anomalocaridid carcasses, but rarely within the matrix of the concretions. This distribution indicates that sulfate reduction around the carcasses was vigorous within otherwise organic-poor sediments resulting in the establishment of prominent chemical gradients around the giant anomalocaridids that led to early precipitation of mineral overgrowth around nonbiomineralized tissues. Rapid precipitation of intergrown silica and Fe chlorite required an abundant source of silica, iron, and aluminum. These ions were likely derived from dissolution of volcanic ash in the sediments. Limited intergrown calcite (d 13C avg. 212.2%o ,n 5 23) precipitated from bicarbonate that was generated largely by sulfate reduction of organic tissues of the carcasses. Whereas Burgess Shale-type preservation of fossils in the Fezouata biota required suppression of degradation, exceptional preservation of anomalocaridids within the siliceous concretions resulted from extensive microbial decomposition of a large volume of organic tissues. Rapid mineralization was facilitated by localization of microbial activity around the large carcasses and must have required an unusually reactive sediment composition.

Environmental control on concretion-forming processes: Examples from Paleozoic terrigenous sediments of the North Gondwana margin, Armorican Massif (Middle Ordovician and Middle Devonian) and SW Sardinia (Late Ordovician)

Concretions of various compositions are common in the Paleozoic terrigenous successions of the north Gondwana margin. This study focuses on phosphatic (P) and siliceous (Si) concretions present in some successions of the Armorican Massif (NW France) and SW Sardinia (W Italy). It shows that they consist of mudstones, fine- to very fine-grained sandstones or shellbeds with a more or less abundant P-cement and form a continuum between a phosphatic end-member and a siliceous biogenic end-member. The P2O5 contents are ranging from 0.26% to 21.5% and are related to apatite. The SiO2 contents vary from 25% to 82% and are linked both to a terrigenous phase and to a biogenic silica phase. Concretions showing the lower P-contents (P2O5<1.5%) are often enriched in biogenic silica (SiO2/Al2O3>5). Comparison with the surrounding sediments shows that all the concretions are enriched in chlorite and in Middle Rare Earth Elements (Las/Gds: 0.12–0.72) and some of them in Y (up to 974ppm), Rare Earth Elements (more than 300ppm) and Sr (260–880ppm).The concretions with highest biogenic silica concentrations are contained in the outer shelf sediments whereas the other concretions are present from the proximal part of the inner shelf to the outer shelf. A genetic model in two stages is proposed. During early diagenesis, the dissolution of shells and degradation of organic matter progressively enrich the pore water in dissolved Si, Ca and P. When the suboxic zone is reached, P-precipitation begins, leading to the formation of protoconcretions. In shallow environments, the relative permeability of sediments and the winnowing or reworking of the upper few centimetres by bottom currents allow for suboxic conditions to be maintained, leading to P-rich concretion formation. In deeper environments, the anoxic zone is reached more rapidly, thereby preventing extensive phosphogenesis. Nevertheless in the protoconcretions the early P-cement preserves pore spaces from compaction. In the presence of biogenic siliceous particles, the fluids are enriched in dissolved silica and diffuse towards the protoconcretions. Silica precipitation can thus occur later in the intergranular spaces.

The corrosion investigation of rebar embedded in the fibers reinforced concrete

One effective method for preventing corrosion of steel reinforcement and improving the mechanical properties of concrete is changing the physical nature of concrete by adding different materials. In this study, we have used polypropylene fibers as an additional material. We have compared the corrosion rate of rebar using different volume ratios and sizes of polypropylene fibers. Reinforcement potential increased as the amount of fibers increased from 0 to 2kgm−3. The polypropylene fibers delay the initial corrosion process by preventing cracking, thereby decreasing permeability of the concrete. In addition, the corrosion rate of concrete samples made with Kish Island coral aggregate was compared to samples made with a siliceous aggregate. The corrosion rate in this concrete is more than twice that in siliceous concrete. We concluded that coral aggregate is improper for making concrete and using in concrete structures in the onshore atmosphere.

Strain model for traditional and self-compacting concrete during fire

In this paper, a complete strain model is derived that describes the strains developed during fire (up to 400 °C) and is based on the model of Anderberg et al., published in 1976. This model describes the total measured deformation as a superposition of four strain types: free thermal strain, instantaneous stress-related strain, creep strain and transient strain. The strains are derived from loading tests on cylinders with dimensions O106 × 320 mm, submitted to load ratios of 0%, 20% and 30% of the initial strength before heating. For damage to the oven to be avoided, the instantaneous stress-related strain is found from Young's modulus tests immediately after cooling. All tests occurred at a heating rate of 5 °C/min, and the specimens were pre-dried to avoid explosive spalling. The investigated concretes are a traditional and a self-compacting concrete with a testing age of about 30 months. Only small differences between both concrete types are found for the transient strain despite the different fracture of cement matrix. For the studied test conditions, the modern siliceous concretes such as self-compacting concrete yielded similar results as the traditional siliceous concretes tested in the 1970s. Copyright © 2012 John Wiley & Sons, Ltd.

Performance testing of engineered corium cooling systems

Abstract The coolability of ex-vessel core debris continues to be an issue of concern in the realm of light water reactor safety. Extensive research into corium/concrete interaction phenomena has been unable to establish the certainty of melt quench and stabilization within the containment boundary for all credible cases of cooling restricted to top flooding. As a result, there has been continuing interest in engineered systems that can augment cooling. This paper describes the testing of two passive cooling concepts that inject water into corium from below via nozzles embedded within the basemat: one with porous concrete nozzles and the other with a type of composite nozzle. The latter supplements water injection with noncondensable gas to stabilize flow and suppress vapor explosions. Each test involved a 136 kg melt composed of 56/23/14 wt% UO 2 /ZrO 2 /siliceous concrete at an initial depth of 30 cm. The setup with the porous concrete nozzles successfully injected water into the melt at heads as low as 2.3 m. The composite nozzle test was partially successful, with three nozzles delivering coolant while a fourth was damaged by the melt and failed to inject water. The melts cooled twice as fast as similar ones tested in a top flooding configuration. These experiments confirmed earlier work at Forschungszentrum Karlsruhe and elsewhere indicating that cooling via bottom water injection is a particularly effective method for quenching ex-vessel corium melts.

Influence of Cooling Methods and Standing Time on Different Aggregate Concrete Strengths after Elevated Temperature

After heated to high temperature, the strength test of concrete cube specimens made by siliceous and calcareous coarse aggregates was carried out. We analyzed the influence of cooling methods and standing time on concrete compressive strength respectively. The test results show that the compressive strength is generally decreased with increase in temperature. The relative residual strength of calcareous aggregate concrete is higher than siliceous aggregate concrete at higher temperature, so siliceous aggregate concrete has more significant fire resistance than calcareous aggregate concrete. Between 200°C and 550°C, the cooling methods have a great influence on concrete strength. The minimum of concrete strength appears at the 28th day after elevated temperature for both calcareous aggregate concrete and siliceous aggregate concrete in air cooling condition, whereas the minimum appears at the first week in water cooling condition. In addition, concrete strength values become steady with the lapse of time after the fire.

Rheological, Mechanical and Structural Performances of Crushed Limestone Sand Concrete

The crushed limestone sand is an abundant material in Tunisia, which induces many environmental problems. Indeed, available stocks of siliceous sand drastically decrease because of its massive use in hydraulic concrete. Some recent research works, carried out in Tunisia, concluded that crushed limestone sand may be used in concrete manufacture instead of siliceous sand traditionally used. In this context, an experimental study was achieved in order to quantify the influence of a partial or total substitution of siliceous sand by crushed limestone sand on hydraulic concrete performances. Preliminary chemical and physical tests on crushed sand indicated that it presented the minimum requirement for its use as aggregate in hydraulic concrete. 79 concretes were then prepared with siliceous sand, crushed limestone sand and a mix of the two sands. Their slump value and compressive strengths were measured on plain concretes. Complementary structural tests on reinforced concrete beam were also performed. The results proved that crushed limestone sand concretes showed workability and mechanical performances closed to those of siliceous sand concretes.

Coefficients of Thermal Expansion of Concrete with Different Coarse Aggregates–Texas Data

Abstract The first section of this paper summarizes the efforts of Texas Department of Transportation (TxDOT) to evaluate the coefficients of thermal expansion (COTEs) of a total of 93 concrete mixtures, of which the only difference is the coarse aggregate incorporated. The mean COTE value of siliceous gravel concrete is about 30 % higher than that of limestone concrete. The data in Texas shows that the upper 50 % COTE values of limestone concrete overlaps the lower 20 % COTE values of siliceous gravel concrete. The results strongly suggest that pre-qualification of coarse aggregate for typical paving concrete in aspect to COTE should be considered. A model by Emanuel and Hulsey is used to back calculate COTE of coarse aggregate. The second section of this article compares the COTE data set on existing pavement measured by Federal Highway Administration with those obtained at TxDOT concrete laboratory.

HECLA experiments on interaction between metallic melt and hematite-containing concrete

In a hypothetical severe accident in a nuclear power plant, molten materials may come into contact with concrete, causing concrete ablation. In five HECLA experiments the interaction between metallic melt and concrete was investigated by pouring molten stainless steel at almost 1800 °C into cylindrical concrete crucibles. The tests were transient, i.e. no decay heat simulation was used. The main objective was to test the behavior of the FeSi concrete, containing hematite (Fe 2O 3) and siliceous aggregates. This special concrete type is used as a sacrificial layer in the Olkiluoto 3 EPR reactor pit, and very scarce experimental data is available about its behavior at high temperatures. It is concluded that no clear differences between the ablation of FeSi concrete and ordinary siliceous concrete were observed. The ablation depths were small, 25 mm at maximum. No dramatic effects, such as cracking of large pieces of concrete due to the thermal shock, took place. An important side result of the test series was gaining knowledge of the properties of the special concrete type. Chemical analyses were conducted and mechanical properties were measured.

European Experiments on 2-D Molten Core Concrete Interaction: HECLA and VULCANO

This paper presents results from two ongoing European experimental programs on molten core concrete interactions: HECLA at VTT and VULCANO at the Commissariat à l’Énergie Atomique. In the HECLA experiments, metallic melt is poured into a cylindrical concrete crucible. The focus is on the initial, pouring phase of the interaction. Therefore, decay heat simulation is not required. The HECLA-2 experiment involved 50 kg of stainless steel at 1700°C and siliceous concrete. The final ablation depths were 25–30 mm in the basemat and ~15 mm in the side wall. The VULCANO VB experiments have been devoted to the study of the interaction of 28 to 45 kg of oxidic corium with silica-rich or limestone-rich concretes. These tests focus on long-term ablation and require the use of induction heating to simulate the decay heat fluxes. Anisotropic ablation between the horizontal and vertical direction has been observed with silica-rich concrete, confirming the CCI tests. A new series of experiments VULCANO VBS has been launched in which there are both oxide and metallic phases in the melt. In these tests, magnetic screening is used so that the induction power is provided almost only to the upper oxidic layer after stratification.Note: Some figures in this paper are in color only in the electronic version.

Simulation of corium concrete interaction in 2D geometry

Benchmarking work was recently performed for the issue of molten corium concrete interaction (MCCI). A synthesis is given here. It concerns first the 2D CCI-2 test with a homogeneous pool and a limestone concrete, which was used for a blind benchmark. Secondly, the COMET-L2 and COMET-L3 2D experiments in a stratified configuration were used as a post-test (L2) and a blind-test (L3) benchmark. More details are given here for the recent benchmark considering a matrix of four reactor cases, with both a homogeneous and a stratified configuration, and with both a limestone and a siliceous concrete. A short overview is given on the different models used in the codes, and the consistency between the benchmark actions on experiments and reactor situations is discussed. Finally, the major uncertainties concerning MCCI are also pointed out.

An improved interface model for molten corium–concrete interaction

In the field of research for Severe Accidents of PWRs, calculation results are needed to estimate when corium achieves basemat melt-through. In this framework, knowledge of the heat transfer coefficient as well as the temperature at the interface between the melt and the solid are key issues. It has been previously emphasized that physico-chemistry of the melt (composition) affects the temperature. However, the effect of gas sparging and liquid concrete release on the mechanical stability of the solid layer and on the interface temperature has not been analysed in detail. ARTEMIS 1D tests were launched to analyse the phenomenology at the interface. A general conclusion for all these tests is that a solid medium enriched in refractory species exists at the interface between the pool and the concrete. Tests 2 and 6, which are close to reactor representative conditions, could be well described with the assumption T interface = T liquidus. The analysis of tests 3 and 4 revealed that the interfacial medium is thicker by a factor of 4–5 times than calculated with the assumption of pure conduction heat transfer. Detailed analysis leads to the conclusion that the interfacial medium is made of a porous layer of refractory particles embedded in a liquid phase. The liquid density difference, between the porous medium and chimneys, results in recirculation of the liquid in the porous layer. This recirculation is responsible for a convective contribution to heat transfer through the porous layer. The convective heat flux is partly linked to cooling of the recirculating liquid, but also to its partial solidification. The solidification results in gradual plugging and enrichment of the porous layer in refractory species and in the increase of the resistance to heat transfer. The phenomena have been modelled and ARTEMIS tests 3 and 4 are well reproduced. The complete plugging of the porous medium, associated with thermodynamic equilibrium at the interface between the solid medium and the pool leads naturally to the solid crust model implemented in TOLBIAC-ICB. The latter model appears, thus, as a simplification of the porous medium approach described here. Thick interfacial layers, which have composition between refractory and corium mixture, have been observed in ACE and MACE tests with LCS (Limestone–Common Sand) or Limestone concrete and can be explained with the proposed model approach. For siliceous concrete, convection within a porous medium is not possible due to the large viscosity.

The COMET-L3 experiment on long-term melt–concrete interaction and cooling by surface flooding

The COMET-L3 experiment considers the long-term situation of corium/concrete interaction in an anticipated core melt accident of a light water reactor after the metal melt is layered beneath the oxide melt. The experimental focus is on the cavity formation in the basemat and the risk of a long-term basemat penetration by the metallic part of the melt. The experiment investigates the two-dimensional concrete erosion in a cylindrical crucible of 60 cm in diameter fabricated from siliceous concrete in the first phase of the test, and the influence of surface flooding in the second phase. The initial mass of the melt was 425 kg steel and 211 kg oxide. Decay heating in the two-component metal and oxide melt is simulated by sustained induction heating of the metal phase that is overlaid by the oxide melt. In the initial phase of the test, the overheated, highly agitated metal melt causes intense interaction with the concrete, which leads to fast decrease of the initial melt overheat and reduction of the initially high concrete erosion rate. Thereafter, the erosion by the metal melt slows down to about 0.07 mm/s into the axial direction. Lateral erosion is by a factor of 3 smaller. Surface flooding of the melt is initiated at 800 s. Flooding does not lead to strong melt/water interactions and to penetration of water into the melt. Concrete erosion continues with about 0.040 mm/s until the melt reaches the maximum erosion limit of the crucible. Post-test analysis of the solidified melt was performed after the crucible was sectioned. The solidified melt shows no indication of water ingression from the upper surface. Tight surface crusts explain poor heat removal to the flooding water and the ongoing concrete erosion also after the top flooding. Details of the experiment are reported. The experiment shall be used for validation of models and computer codes for safety assessment.

Modelling of unbonded post-tensioned concrete slabs under fire conditions

This paper investigates the structural behaviour of unbonded post-tensioned one-way spanning concrete slabs in fire conditions. The slabs were simply supported and reinforced with 15.7 mm nominal diameter seven-wire mono-strand tendons. A nonlinear finite element model for the analysis of post-tensioned unbonded concrete slabs at elevated temperatures was developed. The mechanical and thermal material nonlinearities of the concrete, prestressing tendon and anchorages have been carefully inserted into the model. The interface between the tendon and surrounding concrete was also modelled, allowing the tendon to retain its profile shape during the deformation of the slab. The temperature distribution throughout the slab, time–deflection behaviour, time–longitudinal expansion, time–stress behaviour in the tendon, and the failure modes were predicted by the model and verified against test data. The study has shown that the coefficients of thermal expansion currently used in the European Code for calcareous and siliceous concrete can lead to inaccurate predictions of the structural behaviour. A parametric study was conducted to investigate the effects on the global structural behaviour due to the change in the aggregate type, load ratio and boundary conditions. It was shown that by varying the boundary conditions the fire resistance was greatly affected. Although changing the aggregate type and load ratio affected the time-displacement response, the fire resistance defined by failure of the slab was not affected due to the splitting mode of failure above the tendon locations not being affected by these parameters. Comparison with the codes shows that the UK code BS8110 is generally unconservative, whereas the Eurocode EN1992-1-2 provides reasonable design rules.

A heat transfer analysis of the CCI experiments 1–3

This paper presents an attempt to evaluate the heat transfer rates and gas release rates in the CCI core–concrete interaction experiments 1–3, performed within the OECD MCCI project. A new method for calculating the heat transfer rates has been developed. It is based on calculating integrals of the concrete enthalpies with the help of piecewise exponential interpolation curves. The new method takes into account heat conduction in the concrete. Compared to traditional methods, the new method gives better results during slow concrete ablation, and its time resolution is significantly better. The gas release rates from the concrete were also calculated. A regression analysis was conducted for the heat transfer coefficients and gas release rates. Three correlations for the bubbling-enhanced heat transfer were developed. For the basemat, a single correlation can be used for both siliceous and limestone/common sand (LCS) concrete types. For the sidewall, two different correlations are needed for the two concrete types. With the same superficial gas velocity, the heat transfer rate to siliceous sidewalls is higher than to LCS sidewalls. This suggests that the reason for the different radial ablation rates of the concrete types observed in the tests is not the lower gas content of siliceous concrete.

EXCEPTIONAL FOSSIL PRESERVATION IN THE CONASAUGA FORMATION, CAMBRIAN, NORTHWESTERN GEORGIA, USA

Mudstones and siliceous concretions in the middle Cambrian Conasauga Formation, northwestern Georgia, contain body and trace fossils showing nonmineralized preservation and represent two temporally and spatially different marine environments. Identifiable, nonbiomineralized taxa include components of a Burgess Shale–type biota with red and green algae, primitive sponges, and the arachnomorph arthropod Naraoia compacta . Also exceptionally preserved are the filamentous appendages of a large ptychopariid trilobite and assemblages of oriented hyolithid tests we interpret as priapulid coprolites and cololites. Exceptional preservation in the Conasauga Formation has multiple causes. The Conasauga contains superabundant siliceous concretions, many with skeletal, trace, and some nonbiomineralized fossils. Shale specimens, especially sponges with preserved details, and whole-body trilobite preservations, often have iron (Fe) oxide halos that resulted from a biochemical cascade including bioimmuration, decomposition gas anoxia, Fe-sulfide crystallization, and Fe oxidation. Preservation of soft tissue is also partly attributable to the well-sorted clay matrix of inner shelf Conasauga shales, which allowed mechanical imprinting of body fossils. Several nonbiomineralized fossils show algal overgrowths, suggesting an additional form of bioimmuration. Exceptional preservation in the Conasauga Formation is relatively poor compared with such better-known Cambrian Lagerstatten as the Burgess and Wheeler Shales; nevertheless, it is significant for three reasons. The siliceous concretions are a rare vehicle for exceptional preservation and feature three-dimensional fossils rather than the more common compressed specimens. The older Conasauga biota occupied a shallow-shelf environment, a setting in which exceptional preservation is poorly understood. The Conasauga Formation extends the geographic range of a Burgess Shale–type biota to the extreme southeastern USA.

Radon emanation rates of common partition materials in Hong Kong

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.