Advances in Concrete Binders and Reinforced Concrete

A special issue of Construction Materials (ISSN 2673-7108).

Deadline for manuscript submissions: closed (31 October 2023) | Viewed by 29569

Special Issue Editors


E-Mail Website
Guest Editor
School of Civil Engineering, National Technical University of Athens (NTUA), Athens, Greece
Interests: chemistry of cement; supplementary cementitious materials (metakaolin, fly ash, silica fume and slag); concrete technology (self-compacted concrete, lightweight concrete, smart–self-curing/healing/sensing concrete and fiber-reinforced concrete); durability of concrete; constructions’ service life

E-Mail Website
Guest Editor
Institute of Theoretical and Applied Mechanics of the Czech Academy of Sciences, 19000 Prague, Czech Republic
Interests: cement chemistry; concrete technology; durability of cement-based materials in corrosive environments; microstructural analysis; supplementary cementing materials; magnesium phosphate cements; alkali-activated binders; self-healing; cultural heritage building materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Construction Materials (ISSN 2673-7108) is an international, open access and peer-reviewed journal that publishes research findings and developments in the field of construction materials.

This Special Issue aims to provide insights into the properties and characteristics of different inorganic binders that can be used as the main component in concrete mix designs and reveal their role in the performance of concrete and its applications. Inorganic binders, including Portland cement, alkali-activated materials and magnesium cements, potentially incorporating wastes (fly ash, slags, etc.) or artificial supplementary materials (clays, silica fume, etc.), are welcome to join concrete. Energy-efficient materials, new technologies and techniques (self-healing/curing/sensing, etc.), in addition to concrete designs for optimum performance in terms of mechanical response and/or service life, are also in the scope of this Special Issue.

The length of papers is not restricted so that the experimental and methodical details can be presented. If the full details of the study procedure cannot be included as part of the main manuscript, we also encourage the submission of supplementary documents.

Prof. Dr. Efstratios Badogiannis
Dr. Konstantinos Sotiriadis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Construction Materials is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • concrete
  • inorganic binders
  • supplementary cementing materials
  • wastes
  • alkali-activated materials
  • magnesium cements
  • reinforced concrete
  • corrosion
  • durability
  • energy efficient design
  • performance optimization.

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (11 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

21 pages, 10265 KiB  
Article
Efficiency of CFRP Strengthening Measures for Reinforced Concrete Structural Members Using Toughened Epoxies
by Dimitra V. Achillopoulou, Angeliki Kosta, Nikoleta K. Stamataki, Antonino Montalbano and Fabien Choffat
Constr. Mater. 2024, 4(1), 173-193; https://doi.org/10.3390/constrmater4010010 - 1 Feb 2024
Cited by 1 | Viewed by 1579
Abstract
This paper aims to investigate the interface efficiency of Carbon Fiber Reinforced Polymers (CFRP) adhesively bonded on concrete, a commonly used retrofitting measure applied for enhancing the deformability and strength of decaying structures or existing ones with low capacity. The efficiency quantification is [...] Read more.
This paper aims to investigate the interface efficiency of Carbon Fiber Reinforced Polymers (CFRP) adhesively bonded on concrete, a commonly used retrofitting measure applied for enhancing the deformability and strength of decaying structures or existing ones with low capacity. The efficiency quantification is expressed with the Interface Capacity Index (IC). The index correlates the thickness and strength of each layer of the strengthening system and accounts for the transferred loads (ICL) and the strain distribution that causes the failure propagation on the concrete substrate (ICfp). The investigation focuses on different CFRP strengthening schemes (laminated fabrics, prefabricated plates, Near Surface Mounted bars-NSM) applied to concrete substrates using different adhesive layers. Two cases were studied for different levels of concrete’s integrity: (a) healthy and (b) containing corrosion products. The experimental results were used to calibrate the numerical models and to evaluate the effects of different strengthening strategies. The results show the tendency of the strengthening systems to shift the interface performance from fully elastic to non-linear. Further, the quantification of the efficiency of retrofitting can be addressed by accounting for the mechanical and geometrical properties at the interface level, representing different failure modes and integration levels. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

15 pages, 8175 KiB  
Article
Effect of Water Magnetization Technique on the Properties of Metakaolin-Based Sustainable Concrete
by Ahmed M. Elkerany, Mohamed M. Yousry Elshikh, Ahmed A. Elshami and Osama Youssf
Constr. Mater. 2023, 3(4), 434-448; https://doi.org/10.3390/constrmater3040028 - 22 Nov 2023
Cited by 3 | Viewed by 1544
Abstract
Using metakaolin (MK) in concrete with magnetized water (MW) has a high possibility to enhance concrete suitability. In this study, the effect of using MK and MW on concrete characteristics was studied through testing twelve concrete mixes. Seven ratios of MK were used [...] Read more.
Using metakaolin (MK) in concrete with magnetized water (MW) has a high possibility to enhance concrete suitability. In this study, the effect of using MK and MW on concrete characteristics was studied through testing twelve concrete mixes. Seven ratios of MK were used in this study, namely 0%, 5%, 10%, and 20%, as an alternative to cement and +5%, +10%, and +20% as a cement additive. In addition, five water magnetization methods were applied on MK concrete. In the first stage of this study, the impact of different MK ratios on the workability of concrete, compressive strength, flexural strength, and tensile strength was studied using traditional tap water (TW) as the concrete mixing water. In the second stage, the best mix (best MK ratio) from the first stage was chosen to study the effect of the water magnetization method on concrete properties and to determine the best method for water magnetization. Scanning electronic microscope (SEM) analysis was also carried out on selected mixes to closely investigate the effect of MK and MW on concrete microstructure. The results showed that the best ratio of MK in concrete was +10% (MK as a 10% cement addition), and the best water magnetization method was to pass the water through 1.6 tesla then through 1.4 tesla magnetic fields. The SEM analysis confirmed the absence of pores after using MW instead of regular TW by increasing the calcium silicate hydrate (CSH) gel and reducing calcium hydroxide (CH). Using MK and MW enhanced the compressive strength by up to 33%, 32%, and 27% at 7, 28, and 365 days, respectively, and MW enhanced the workability by up to 3% compared to that of the control mix. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

15 pages, 11853 KiB  
Article
Effect of Electrochemical Corrosion on the Properties of Modified Concrete
by Anastasiya Gordina, Aleksandr Gumenyuk, Irina Polyanskikh, Grigorij Yakovlev and Vít Černý
Constr. Mater. 2023, 3(2), 202-216; https://doi.org/10.3390/constrmater3020013 - 25 Apr 2023
Cited by 1 | Viewed by 1871
Abstract
Analysis of the use of reinforced concrete structures confirmed the destruction of reinforced products based on Portland cement due to stray currents, which makes it impossible to achieve the required durability and reliability of structures. The present work shows the results of a [...] Read more.
Analysis of the use of reinforced concrete structures confirmed the destruction of reinforced products based on Portland cement due to stray currents, which makes it impossible to achieve the required durability and reliability of structures. The present work shows the results of a study on the diffusion permeability of samples with different degrees of electrical conductivity. The relative value of the electrode potential was measured by the open circuit potential method. The novelty of this work is its analysis of the quantitative and qualitative characteristics of the structure of the mineral matrix with specified electrical properties after long-term exposure to electrochemical corrosion. In this work, an assessment was carried out, for the first time, on the effects of electrochemical corrosion on modified composites with predominantly electrically conductive and electrically insulating properties. An increase in the electrical conductivity of the composite was found to reduce the potential difference. The use of such composites helped protect the reinforcement from electrochemical corrosion. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

16 pages, 8807 KiB  
Article
Effect of Excessive Bleeding on the Properties of Cement Mortar
by Mimoune Abadassi, Youssef El Bitouri, Nathalie Azéma and Eric Garcia-Diaz
Constr. Mater. 2023, 3(2), 164-179; https://doi.org/10.3390/constrmater3020011 - 21 Apr 2023
Cited by 2 | Viewed by 2934
Abstract
The bleeding of cementitious materials corresponds to the settlement of the granular skeleton accompanied by the accumulation of water at the surface (bleed water). Part of this water (internal bleeding) remains trapped under the aggregates (sand or gravel) or the reinforcements. The excess [...] Read more.
The bleeding of cementitious materials corresponds to the settlement of the granular skeleton accompanied by the accumulation of water at the surface (bleed water). Part of this water (internal bleeding) remains trapped under the aggregates (sand or gravel) or the reinforcements. The excess of this trapped water can weaken the bond between the cementitious matrix and the aggregates (or the reinforcements), which affects the mechanical performance and durability of the material. This study aims to investigate the effect of excessive bleeding induced by superplasticizer on the properties of mortars. For this, a study of cement paste bleeding in the presence of superplasticizer was carried out. The effects of the water-to-cement ratio (w/c) and the superplasticizer (SP) dosage on this bleeding have been characterized. Then, the influence of the proportion of sand on the bleeding was examined by varying the sand/cement (s/c) ratio. The water trapped by sand (internal bleeding) was determined by the difference between the external bleeding on the cement paste and the external bleeding on the corresponding mortar. The results show that the internal bleeding increases with the s/c ratio and the SP dosage, until it reaches a plateau. The effect of the internal bleeding on the mechanical properties and the porosity of the mortar were then examined. Microscopic observations were made to assess the quality of the paste/sand bond. The results showed that the internal bleeding causes a degradation of the paste/sand bond (a more porous bond), resulting in a decrease in the mechanical strength (by 30% for compressive strength and 25% for flexural strength) of the hardened mortar. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

24 pages, 18698 KiB  
Article
Cyclic Behavior of FRP Strengthened Beam-Column Joints under Various Concrete Damage Levels
by Rajai Al-Rousan, Osama Nusier, Khairedin Abdalla, Mohammad Alhassan, Emmanouil A. Vougioukas, Athanassios A. Stamos and Nikos D. Lagaros
Constr. Mater. 2023, 3(1), 38-61; https://doi.org/10.3390/constrmater3010004 - 28 Jan 2023
Cited by 5 | Viewed by 2647
Abstract
This paper is intended to examine the efficiency of utilizing the FRP composite material with an externally bonded technique in enhancing the behavior of the damaged B-C joints and controlling their failure mode using the NLFEA approach. At first, the modeled Beam-Column joint [...] Read more.
This paper is intended to examine the efficiency of utilizing the FRP composite material with an externally bonded technique in enhancing the behavior of the damaged B-C joints and controlling their failure mode using the NLFEA approach. At first, the modeled Beam-Column joint was validated as per the previously-attained experimentally-attained results. Later, the model was widened to experiment with the impact of axial-column load and the concrete compressive strength on the reinforced and un-reinforced models with FRP. To run the experiment, there were three cases of applying the axial column load: no load applied (0%), applying 25%, applying 50%, and applying 75%, while the concrete compressive strength degradation level was (0% damage), (25% damage), and (50% damage). All models were evaluated for structural performance, considering: the failure mode, stresses distribution, and the ultimate capacities in pulling and pushing with its corresponding displacements. However, the horizontal load-displacement hysteretic loops and envelopes, stiffness degradation, displacement ductility, and energy dissipation were reported. The experimental results revealed that using FRP to externally-reinforce B-C joints improved overall cyclic performance, as the FRP caused a rise in the ultimate load capacity, horizontal displacement, ductility of displacement, and displacement energy dissipation, while it slowed down the stiffness degradation. In addition, the FRP material converted the failure mode of the region between the joint and column from brittle to ductile due to the formation of a plastic hinge only on the side of the beam when the axial column load exceeded 25%. It must be noticed that when the column’s axial load is less than 25%, the ultimate capacity of axial load and resultant deflection is solely improved. However, it has been stated that increasing the column’s axial loading by 25% increases the resulting stiffness degradation by 3% for undamaged joints, which further increases by 16% for each increased damage level. In contrast, the absorbed energy is increased by 170% under axial loading, increasing by 25%, which is reduced to only one-fourth under the various damage levels. Generally, the resulting observations help specialized engineers retrofit appropriate B-C joints in already-standing buildings due to their accuracy. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

22 pages, 4353 KiB  
Article
Influence of the Type of Cement on the Durability of Concrete Structures Exposed to Various Carbonation Environments in Greece: A Contribution to the Sustainability of Structures
by Christos Tassos, Kosmas K. Sideris, Alexandros Chatzopoulos, Emmanouel Tzanis and Marios S. Katsiotis
Constr. Mater. 2023, 3(1), 14-35; https://doi.org/10.3390/constrmater3010002 - 14 Jan 2023
Cited by 5 | Viewed by 3614
Abstract
The research objective of this paper is to investigate the effect of different types of cement and different climatic conditions on the durability of reinforced concrete structures to understand and address issues of durability and erosion. The types of cement used were CEM [...] Read more.
The research objective of this paper is to investigate the effect of different types of cement and different climatic conditions on the durability of reinforced concrete structures to understand and address issues of durability and erosion. The types of cement used were CEM I 42.5N, CEM II/A-M (P-LL) 42.5N and CEM II/B-M (W-P-LL) 32.5N. Mixtures of three different cement mortars and six different concretes were prepared with these three types of cement. Cement mortars were produced according to the European standard EN 196-1. Concrete mixtures were of the strength classes C25/30 and C30/37. Concrete mixtures produced according to the specifications of the European standard EN 206 may have a shorter service life due to carbonation-induced corrosion if the choice of the cement type is not made carefully. The results indicate that the carbonation rate of concrete mixtures is significantly influenced by the type and strength class of the cement used. Using meteorological data from six regions of Greece, an empirical carbonation prediction model for these regions was obtained. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

14 pages, 16093 KiB  
Article
A Novel Approach for Maintenance and Repair of Reinforced Concrete Using Building Information Modeling with Integrated Machine-Readable Diagnosis Data
by Hendrik Morgenstern and Michael Raupach
Constr. Mater. 2022, 2(4), 314-327; https://doi.org/10.3390/constrmater2040020 - 16 Dec 2022
Cited by 2 | Viewed by 2756
Abstract
Building Information Modeling (BIM) is increasingly establishing a model-based work process in the construction industry. Though it can be considered the standard for the planning of new buildings, the use cases for existing buildings are still limited. Nonetheless, BIM models provide promising possibilities [...] Read more.
Building Information Modeling (BIM) is increasingly establishing a model-based work process in the construction industry. Though it can be considered the standard for the planning of new buildings, the use cases for existing buildings are still limited. Nonetheless, BIM models provide promising possibilities which are increasingly being researched in different fields of application. At the Institute for Building Materials Research (ibac) at RWTH Aachen University, a novel approach for maintenance and repair of reinforced concrete is being developed, using BIM models enriched with machine-readable diagnosis data. This paper proposes a digital workflow and highlights the added value for planning repair measures. Using BIM in maintenance and repair can accelerate the planning process and decrease the required material consumption for the execution. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

17 pages, 4566 KiB  
Article
Effect of Metakaolin and Lime on Strength Development of Blended Cement Paste
by Kosar Hassannezhad, Yasemin Akyol, Mehmet Can Dursun, Cleva W. Ow-Yang and Mehmet Ali Gulgun
Constr. Mater. 2022, 2(4), 297-313; https://doi.org/10.3390/constrmater2040019 - 14 Nov 2022
Cited by 8 | Viewed by 3742
Abstract
To develop a more reactive pozzolan for supplementary cementitious materials (SCMs), the co-calcination of kaolinite and limestone was investigated for its contribution to hydration of blended cement. Kaolinite (with ~50 wt% quartz impurity) was calcined at 700 °C, and a mixture of kaolinite [...] Read more.
To develop a more reactive pozzolan for supplementary cementitious materials (SCMs), the co-calcination of kaolinite and limestone was investigated for its contribution to hydration of blended cement. Kaolinite (with ~50 wt% quartz impurity) was calcined at 700 °C, and a mixture of kaolinite and limestone was calcined at 800 °C. These activated SCMs were added to ordinary Portland cement (OPC), replacing ca. 30 wt% of the OPC. The compressive strength of these blended cement paste samples was measured after 28 and 90 days, while the hydration products and microstructural development in these blended cement pastes were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results revealed that adding free lime to OPC, together with metakaolin, led to enhanced compressive strength. The compressive strength of this new blended cement paste reached 113% and 112% of the compressed strength of pure OPC paste after 28 and 90 days of hydration, respectively. Furthermore, this study showed that the improvement was due to the increased consumption of Portlandite (CH), the formation of calcium aluminosilicate hydrate (CASH), and the reduction of porosity in the sample containing free lime and metakaolin. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

21 pages, 5324 KiB  
Article
Self-Compacting Cementitious Composites with Heavy Fuel Fly Ash Replacement
by Antroula Georgiou, Nicolaos Chousidis and Ioannis Ioannou
Constr. Mater. 2022, 2(4), 276-296; https://doi.org/10.3390/constrmater2040018 - 10 Nov 2022
Cited by 1 | Viewed by 2247
Abstract
Sustainability in construction is related to the use of industrial by-products, such as fly ash (FA). FA varies in chemical/mineralogical composition, depending on the raw materials burnt during its production. While FA produced from coal-fired power stations is extensively used in cementitious composites, [...] Read more.
Sustainability in construction is related to the use of industrial by-products, such as fly ash (FA). FA varies in chemical/mineralogical composition, depending on the raw materials burnt during its production. While FA produced from coal-fired power stations is extensively used in cementitious composites, heavy oil FA produced from the firing of heavy fuels (e.g., mazut or diesel) remains largely unused. This paper focuses on the novel use of heavy fuel fly ash (HFFA), as a replacement of Class F FA, in high-volume fly ash self-compacting composites. Two different grain size distributions of HFFA were used in quantities 5–15% w/w of cement and Class F FA for the production of the composites. The assessment of the physico-mechanical properties and microstructure of the end-products at different curing ages suggests that HFFA may be used at quantities ≤10% w/w, without any negative effects. In fact, depending on the quantity and grain size distribution of the HFFA, this may even improve some of the properties of the end-products in the long term, provided that a careful mix design is adopted. The findings show the potential of sustainable reuse of HFFA and are beneficial for its incorporation into design codes. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

17 pages, 4058 KiB  
Article
Investigation of Rheological Test Methods for the Suitability of Mortars for Manufacturing of Textile-Reinforced Concrete Using a Laboratory Mortar Extruder (LabMorTex)
by Matthias Kalthoff, Michael Raupach and Thomas Matschei
Constr. Mater. 2022, 2(4), 217-233; https://doi.org/10.3390/constrmater2040015 - 29 Sep 2022
Cited by 6 | Viewed by 2468
Abstract
One of the promising technologies to produce carbon textile-reinforced concrete structures is extrusion. For defect-free extrusion, high requirements are placed on the fresh concrete, since it must be transportable through the augers in the extruder and must not change the desired geometric shape [...] Read more.
One of the promising technologies to produce carbon textile-reinforced concrete structures is extrusion. For defect-free extrusion, high requirements are placed on the fresh concrete, since it must be transportable through the augers in the extruder and must not change the desired geometric shape after leaving the mouthpiece. For the rheologic description of suitable concretes or mortars for the extrusion process, there is currently a lack of test methods to characterise the fresh concrete before extrusion. At present, new mixtures are first tested in elaborate trials on laboratory extruders before they can be transferred to production scale. The development of compounds is strongly dependent on the know-how and experience of the users. Within the scope of this paper, different methods were investigated and systematic suitability tests for a successful extrusion have been carried out. The results show that the fresh mortar can only be roughly described by the measured data during the mixing process, such as the temperature or the torque. The use of a capillary rheometer only allows a basic characterisation of the fresh mortar. A clear differentiation of the fresh mortar can be made with the help of sphere penetration tests. These allow the mortar to be classified as unsuitable for the extrusion process or as extrudable before the extrusion process, and the suitability of new mixtures can be assessed in advance. The newly developed method offers the possibility of greatly accelerating the implementation of new formulations for the extrusion process, regardless of the experience of the subsequent users, and reducing the need for complex experiments using laboratory extruders. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

19 pages, 4763 KiB  
Article
Mechanical Properties of Rubberised Concrete Confined with Basalt-Fibre Textile-Reinforced Mortar Jackets
by Ioanna Skyrianou, Lampros N. Koutas and Christos G. Papakonstantinou
Constr. Mater. 2022, 2(3), 181-199; https://doi.org/10.3390/constrmater2030013 - 10 Aug 2022
Cited by 6 | Viewed by 2373
Abstract
This paper presents an experimental investigation of the mechanical properties of rubberised concrete confined with basalt-fibre textile-reinforced mortar (TRM) jackets. The main aim is to evaluate the effectiveness of the TRM confinement scheme on cylindrical rubberised concrete specimens by examining five different mixtures [...] Read more.
This paper presents an experimental investigation of the mechanical properties of rubberised concrete confined with basalt-fibre textile-reinforced mortar (TRM) jackets. The main aim is to evaluate the effectiveness of the TRM confinement scheme on cylindrical rubberised concrete specimens by examining five different mixtures (rubber content ranging from 10.5% up to 42% of the total aggregate volume), including a plain concrete reference mixture. Unconfined and confined specimens with either one or two TRM layers were subjected to monotonic axial loading. The results indicate a decrease in the compressive strength of unconfined concrete as the rubber content increased. The stress–strain curves of rubberised concrete became smoother at the peak as the rubber content increased, also exhibiting increased axial strain capacity post-peak. Rubberised concrete exhibited less brittle failure than plain concrete, accompanied by increased lateral dilation. Confinement with TRM increased the compressive strength, while also enhanced the performance in terms of toughness and axial deformation capacity compared to unconfined concrete. Overall, it is concluded that there is a promising potential for using TRM-confined rubberised concrete in applications with ductility demands and low environmental footprint specifications. Full article
(This article belongs to the Special Issue Advances in Concrete Binders and Reinforced Concrete)
Show Figures

Figure 1

Back to TopTop