Partner: Wojciech Kubissa

Warsaw University of Technology (PL)

Recent publications
1.Jaskulski R., Glinicki M.A., Ranachowski Z., Kubissa W., Organic phosphorus compounds as heat release regulators in hardening shielding concrete, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2019.03.081, Vol.209, pp.167-175, 2019
Abstract:

The paper presents the results of the study of the influence of the addition of retarding superplasticising admixture based on triisobutyl phosphate and modified phosphonates on the amount of heat generated by hardening shielding concrete. A four-point measurement of the heat generated during the hardening of concrete with an admixture dose of 0, 0.5, 1.0 and 2.0% by weight of the cement was made and the concurrent measurement of the heat released by the hardening cement paste was measured with an isothermal calorimeter. Based on the results from the calorimeter, the effect of the admixture on the temperature field in the hardening concrete mass elements was simulated for different aggregates. The results indicate that the admixture clearly lowers the temperature gradient in hardening mass concrete. In the simulations, the most clear effect was achieved in the case of concrete with barite aggregate, where the gradient value was reduced from 10 C/m to 8 C/m for an admixture content equal to 2.0%. 2019 Elsevier Ltd. All rights reserved.

Keywords:

Temperature gradient, Heat release, Shielding concrete, Mass concrete, Fresh concrete, Phosphorus compounds

Affiliations:
Jaskulski R.-other affiliation
Glinicki M.A.-IPPT PAN
Ranachowski Z.-IPPT PAN
Kubissa W.-Warsaw University of Technology (PL)
2.Jaskulski R., Glinicki M.A., Kubissa W., Dąbrowski M., Application of a non-stationary method in determination of the thermal properties of radiation shielding concrete with heavy and hydrous aggregate, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, ISSN: 0017-9310, DOI: 10.1016/j.ijheatmasstransfer.2018.07.050, Vol.130, pp.882-892, 2019
Abstract:

Results of measurements of the specific heat and the thermal conductivity of concrete with blended special aggregate for neutron and gamma radiation shielding are presented. Experimental tests were performed on concrete with heavyweight aggregate (magnetite, barite), hydrogen-bearing aggregate (serpentine) and amphibolite aggregate. The thermal properties of concrete were determined using a nonstationary method. The highest specific heat was found for concrete with serpentine aggregate. Simple models for predicting the specific heat and the thermal conductivity on the basis of concrete mix design were evaluated to include the blends of heavyweight and hydrogen-bearing aggregates. The thermal conductivity of concrete was found to be linearly dependent on the concrete density in the range from 2200 to 3500 kg/m3. Its increase due to water saturation of concrete was not dependent on the open porosity of concrete. It was found that the specific heat can be fairly well predicted using the rule of mixtures formula. The thermal conductivity of concrete can be approximately predicted using a parallel model in the case of water-saturated concrete. The thermal conductivity prediction for dry concrete is also discussed.

Keywords:

Blended aggregate, Concrete mix design, Density, Non-stationary method, Open porosity, Thermal properties, Thermal conductivity, Specific heat, Radiation shielding

Affiliations:
Jaskulski R.-IPPT PAN
Glinicki M.A.-IPPT PAN
Kubissa W.-Warsaw University of Technology (PL)
Dąbrowski M.-IPPT PAN
3.Kubissa W., Glinicki M.A., Dąbrowski M., Permeability testing of radiation shielding concrete manufactured at industrial scale, MATERIALS AND STRUCTURES, ISSN: 1359-5997, DOI: 10.1617/s11527-018-1213-0, Vol.51, No.83, pp.1-15, 2018
Abstract:

The effect of the composition of industrial concrete designed for radiation shielding structures on the air permeability and the diffusion of moisture was studied. The mix design for heavyweight concrete of bulk density 3168–3317 kg/m3 was developed using barite and magnetite aggregate and cements blended with fly ash and blastfurnace slag. Structural elements, like columns of a height of 4 m and massive blocks made of mixtures with different cements were manufactured using ready mixed concrete pumped into the formwork. Core specimens were taken from the elements at different locations. The air permeability index was tested using Autoclam device. Evaluation of the quality of concrete on the basis of API results varied from “very good” to “good”. The moisture distribution inside concrete specimens was equilibrated to RH = 60 ± 5%. Observation of RH changes allowed to determine the moisture diffusion coefficient. Significant differences of the permeability and moisture diffusion coefficient depending on the location of the core specimens drilling and mix design of concrete were found. The D coefficient provided a good reflection of the different quality of heavyweight concrete in structural elements.

Keywords:

Air permeability, Autoclam, Barite, Blended cement, Cracking, Heavyweight aggregate, Magnetite, Moisture diffusion, Radiation shielding concrete, Relative humidity

Affiliations:
Kubissa W.-Warsaw University of Technology (PL)
Glinicki M.A.-IPPT PAN
Dąbrowski M.-IPPT PAN
4.Kubissa W., Glinicki M.A., Influence of internal relative humidity and mix design of radiation shielding concrete on air permeability index, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2017.04.177, Vol.147, pp.352-361, 2017
Abstract:

The permeation properties of concrete are strongly influenced by the degree of saturation of capillary pores. Test results of the Autoclam air permeability index (API) of radiation shielding concrete are presented. Concrete specimens were made with CEM I and CEM III/A cements and special aggregates for radiation shielding: crushed barite, magnetite, serpentine and amphibolite. Two procedures of accelerated drying with simultaneous measurement of moisture distribution in the specimens were proposed. The specimens were tested at different RH levels from a fully saturated state to an oven dried state. The linear relationship between the API and RH was obtained. Effects of heavyweight and hydrogen-bearing aggregates on air permeability index were revealed.

Keywords:

Autoclam air permeability, Relative humidity, Heavyweight aggregate, Barite, Magnetite, Serpentine, Radiation shielding concrete, Slag cement

Affiliations:
Kubissa W.-Warsaw University of Technology (PL)
Glinicki M.A.-IPPT PAN