Browsing by Author "Sutcu M."

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Basalt fiber reinforced foam concrete with marble waste and calcium aluminate cement
(2023-02-01) Bayraktar O.Y.; Yarar G.; Benli A.; Kaplan G.; Gencel O.; Sutcu M.; Kozłowski M.; Kadela M.
As a typical cellular lightweight material, foam concrete is produced by mixing cement, water, aggregate and a suitable foaming agent and has a density usually below 1600 kg/m3. The large number of air spaces present in foam concrete ensures that the concrete has advantages such as lightweight, high fluidity during pouring, excellent thermal and sound insulation, superior fire resistance, and outstanding energy absorption capacity. Its high porosity and the connectivity of the pores, which can allow the entry of negative substances into the concrete environment, cause foam concrete to have a very low physico-mechanical and durability performance. To eliminate or reduce these disadvantages, this study adopted the use of basalt fibers (BF) as eco-friendly fiber type and calcium aluminate cement (CAC) as aluminous cement with waste marble powder (WMP) as aggregates in foam concrete. In that respect, 9 mixes with varying content of foaming agent (FC) and basalt fiber have been prepared. Assessment of mechanical performance was based on compressive and flexural strength after 6 h, 1, 7, and 28 days. Dry bulk density, thermal conductivity, porosity, water absorption, and sorptivity of the concretes were determined. Durability characteristics of the concretes were examined by dry shrinkage, high temperature, magnesium sulfate, sulfuric, and hydrochloric acids. The obtained results showed that the content of BF affected the compressive strength of the mixtures slightly negatively or positively depending on the FC. The lowest value in thermal conductivity was gained as 0.645 (W/m K) for the mixture incorporating 1% BF and 50 kg/m3 foam quantity. In addition, the foam concrete incorporating foam of 30 kg/m3 and 1% BF showed the best resistance against MgSO4. The mixture with 2% BF and 30 kg/m3 FC exhibited the lowest mass loss after HCI exposure.
Characteristics, energy saving and carbon emission reduction potential of gypsum wallboard containing phase change material
(2022-11-25) Yaras A.; Ustaoglu A.; Gencel O.; Sarı A.; Hekimoğlu G.; Sutcu M.; Erdogmus E.; Kaplan G.; Bayraktar O.Y.
Phase change materials (PCM) used in the development of building materials with thermal energy storage (TES) capacity can minimize temperature fluctuations by reducing the heating and cooling load in building envelopes due to their energy storage/release properties. The present study aims to produce, characterize and measure energy performance under real weather conditions of novel gypsum wallboard containing shape-stable attapulgite (ATP) based composite PCM as TES material. Shape-stable composite PCM was prepared by impregnating 1-Dodecanol (DD) into attapulgite (ATG) and then incorporated with gypsum in volume fraction of 25 and 50 %. The impacts of the shape stable ATG/DD composite PCM additive on the thermo-physical and mechanical properties were systematically assessed. The DCS measurements revealed that the shape-stable ATG/DD composite melts at 20.06 °C with a melting enthalpy of 115.9 J/g while the gypsum/shape-sable ATG/DD (50 v/v%) melts at 20.03 °C with melting enthalpy of 20.06 J/g. Thermoregulation tests demonstrated that the indoor temperatures of the test room made by gypsum/shape-stable composite PCM were about 1.2 °C–2.66 °C warmer than that of the reference gypsum room for about 6–12 h in a cold weather. Theoretical calculations showed that the thermal enhanced gypsum wallboard, because of its TES capability, has a favorable future in terms of energy savings and low CO2 emission.
Development, characterization, and performance analysis of shape-stabilized phase change material included-geopolymer for passive thermal management of buildings
(2022-12-01) Gencel O.; Harja M.; Sarı A.; Hekimoğlu G.; Ustaoğlu A.; Sutcu M.; Erdogmus E.; Kaplan G.; Bayraktar O.Y.
The cooperation between phase change materials (PCMs) and geopolymer (GP) is energy-efficient way for improving the thermal performance of construction materials. This study discusses the effect of PCM combination with GP matrix on obtained concretes' mechanical and thermal properties. Attapulgite/lauric-capric acid eutectic mixture (ATP/LCEM) composite was fabricated as shape-stable composite phase change material (SSPCM) and then integrated with GP concrete (GPC) for improvement of the thermal mass of buildings. Thermal, mechanical, physical, morphological, thermal energy storage (TES) characteristics, and solar thermoregulation performances of the developed GPC-SSPCMs were experimentally characterized. The compressive strength was found over 6 MPa for GPC without aggregates (only SSPCM). The compressive and flexural strengths were relatively low, but above the requirements of the current standards. Other properties as thermal conductivity and solar performance make the produced GPC-SSPCMs promising materials for advanced TES applications in buildings. The apparent porosity was around 45% for GPC-SSPCM-50 and 63% for GPC-SSPCM-100, while water adsorption around 21% for GPC-SSPCM-50 and 30% for GPC-SSPCM-100. Thermal conductivity values of 0.375 W/mK for GPC without aggregates recommended this material as an insulator. The produced SSPCM composite melts at 19.00°C with corresponding latent heat of 73.9 J/g, while the GPC-SSPCM melts at 18.30°C with corresponding latent heat of 6.57 J/g. Based on the obtained outcomes, the energy-saving was determined as 5.56 kWh, which is corresponding to the CO2 saving of 15 kg-CO2, 14.68 kg-CO2, and 2.41 kg-CO2 in case of using coal, natural gas, or electricity, respectively as energy source.
Effect of waste marble powder and rice husk ash on the microstructural, physico-mechanical and transport properties of foam concretes exposed to high temperatures and freeze–thaw cycles
(2021-07-12) Gencel O.; Benli A.; Bayraktar O.Y.; Kaplan G.; Sutcu M.; Elabade W.A.T.
An experimental program was performed to evaluate the impact of rice husk ash (RHA) as cement replacement and waste marble powder (WMP) as sand replacement on the microstructural, mechanical and transport properties of foamed concrete exposed to high temperature and freeze–thaw cycles. For this, Portland Cement (PC) was replaced by RHA at 10% and 20%wt of binder and silica sand was replaced by WMP at 25% and 50%wt of fine aggregates to cast foamed concrete mixtures. Two different foam contents of 40 kg/m3 and 80 kg/m3 were used in the production of foamed concretes with water/binder (w/b) ratio of 0.70. Two reference mixtures were produced from silica sand and without RHA at each foam content. Other foam concretes were fabricated from 25% and 50% WMP instead of silica sand and 10% and 20% RHA instead of cement. Fresh properties of mixtures were evaluated by performing slump test. Transport properties of foam concretes were investigated, including porosity, sorptivity and water absorption after 90 days curing. Mechanical properties of foam concretes were investigated, including compressive and flexural strength ultrasonic pulse velocity (UPV) after 7, 28 and 90 days. Drying shrinkage and thermal conductivity of concretes were also studied after 90 days. Durability of concretes were also investigated after exposure to the temperature of 200, 400, 600 and 800 °C and freeze–thaw (F-T) cycles of 100 and 200 in addition to microstructure investigations. Results show that 10% RHA as cement substitute and 50% WMP as sand substitute give optimum percentage especially at late-age of 90 days at foam content of 40 kg/m3. The lowest drying shrinkage and sorptivity were obtained by using 10%RHA and 25%WMP. The results also indicate that water cooled specimens showed more strength loss than air cooled specimens after 200 °C. The worst F-T performance was obtained for the mixture containing 10% RHA and without WMP by 43.8 and 59.8% strength reductions.
Foam Concrete Produced with Recycled Concrete Powder and Phase Change Materials
(2022-06-01) Gencel O.; Nodehi M.; Hekimoğlu G.; Ustaoğlu A.; Sarı A.; Kaplan G.; Bayraktar O.Y.; Sutcu M.; Ozbakkaloglu T.
In construction industry, phase change materials (PCMs), have recently been studied and found effective in increasing energy efficiency of buildings through their high capacity to store thermal energy. In this study, a combination of Capric (CA)-Palmitic acid (PA) with optimum mass ratio of 85–15% is used and impregnated with recycled concrete powder (RCP). The resulting composite is produced as foam concrete and tested for a series of physico-mechanical, thermal and microstructural properties. The results show that recycled concrete powder can host PCMs without leaking if used in proper quantity. Further, the differential scanning calorimetry (DSC) results show that the produced RCP/CA-PA composites have a latent heat capacity of 34.1 and 33.5 J/g in liquid and solid phases, respectively, which is found to remain stable even after 300 phase changing cycles. In this regard, the indoor temperature performance of the rooms supplied with composite foams made with PCMs, showed significantly enhanced efficiency. In addition, it is shown that inclusion of PCMs in foam concrete can significantly reduce porosity and pore connectivity, resulting in enhanced mechanical properties. The results are found promising and point to the suitability of using RCP-impregnated PCMs in foam composites to enhance thermo-regulative performance of buildings. On this basis, the use of PCMs for enhanced thermal properties of buildings are recommended, especially to be used in conjunction with foam concrete.
Investigation of physico-mechanical, thermal properties and solar thermoregulation performance of shape-stable attapulgite based composite phase change material in foam concrete
(2022-04-01) Gencel O.; Ustaoglu A.; Benli A.; Hekimoğlu G.; Sarı A.; Erdogmus E.; Sutcu M.; Kaplan G.; Yavuz Bayraktar O.
Thermal energy storage (TES) by means of phase change materials (PCM) is of great concern to decrease heating and cooling loads. In building envelopes, one of the most efficient TES methods is integration of PCMs with construction materials for preventing temperature fluctuations by taking advantage of energy storage/release feature of PCMs. Aim of this research was to develop novel foam concretes containing shape-stable attapulgite (ATP) based composite PCM as TES material. Shape-stable ATP/Capric-Myristic acid eutectic mix composite (ATP/C-M) was incorporated into foam concrete at three different ratios (15, 30 and 45 wt%) and characterized. Impacts of ATP/C-M inclusion on physico-mechanic and TES characteristics of foam concretes including composite PCM (FCPCM) were worked systematically. DSC results showed that ATP/C-M composite melts at 22.12 °C with latent heat storage capacity of 74.97 J/g, whereas FCPCM-45 melts at 21.05 °C with latent heat storage ability of 10.98 J/g. Inclusion of ATP/C-M instead of silica sand decreased flow diameter of foam concretes. Compared to reference mixture FCPCM-0, compressive strengths of FCPCM-15, FCPCM-30 and FCPCM-45 samples were reduced in the range of 11–46% while reduction in flexural strength was found to be about 35–57% at 28th day. All FCPCM samples showed lower thermal conductivity values than the specified value and could be defined as better insulation materials. Solar thermoregulation performances of foam concretes containing ATP/C-M were comparatively tested in laboratory and also actual ambient conditions. Results showed that foam concretes with acceptable mechanical properties can be used for internal temperature controlling and energy saving in buildings.
Physico-mechanical, durability and thermal properties of basalt fiber reinforced foamed concrete containing waste marble powder and slag
(2021-06-21) Yavuz Bayraktar O.; Kaplan G.; Gencel O.; Benli A.; Sutcu M.
Recently, the usage of industrial wastes for concrete production has played an important role for developing environmentally friendly building materials. This work focused on investigating physico-mechanical, durability and thermal properties of basalt fibers (BF) reinforced foamed concrete containing waste marble powder (WMP) and ground granulated blast furnace slag (GGBFS). Foamed concretes were fabricated with 50 kg/m3 and 100 kg/m3 contents of a protein-based foaming agent at 0.75 water/binder (w/b) ratio. Two control mixtures in which silica sand used as fine aggregates and containing no BF were developed at each foam content. Other foamed mixtures were produced with WMP as fine aggregates and GGBFS as white Portland cement (WPC) replacement at the rates of 0%, 30% and 60%. BF were also added to the mixtures at the rates of 0%, 1% and 2% by weight of cement. Fresh properties of mixtures investigated were slump and fresh unit weight. Experiments were also fulfilled to evaluate 7, 28, 90 and 180-day water-cured mechanical strengths. Porosity, water absorption and sorptivity were studied after 28 aged cured specimens. Dry unit weight, thermal conductivity and drying shrinkage properties of foamed concrete specimens were assessed on 28 aged specimens. High temperature and freeze–thaw durability of foamed concrete specimens were also examined. Results indicated that very high compressive and flexural strength enhancements of 179.49%, 141.79% and 139.91%, 93.18%, at 7 and 28 days were obtained using WMP and BF addition respectively. Coupling use of 30% GGBFS and 1%BF revealed the highest compressive strength of 32.57 MPa and lowest porosity value of 14.8% at foam content of 50 kg/m3.