Cagla Meral

With the growing need for residential buildings as a result of population growth, the building sector is a high-priority area in climate change due to its large share of CO 2 emissions, the significant energy saving opportunities it represents, and the increasing expectations for occupant comfort. This paper presents the results of climate change impact assessment on a typical mid-rise residential building in four representative cities with different climatic characteristics in Turkey. Three different scenarios that characterize different solutions towards space cooling are developed, from naturally ventilated to fully air-conditioned. The energy requirements and corresponding CO 2 emissions due to space conditioning as well as occupant thermal comfort are the investigated building performance metrics. The preliminary results based on energy simulations indicate that pronounced overheating will be experienced in the future, which will have a strong effect on cooling energy use and/or occupant comfort. The projected energy demand also points to the future need to explore measures for climate change adaptation of buildings and the importance of the decarbonization of the electricity industry for climate change mitigation. The analysis results presented in this paper provide a basis for future studies on building retrofit for climate change.

Perlite is a volcanic glass which has high amount of silica and alumina. Those properties make it a candidate, if finely ground, for being used as a pozzolan. The studies on the pozzolanic properties of perlite are very limited, and none of them has dealt with the use of perlite in the blended cement production. The aim of this study is to investigate the pozzolanic properties of perlite, and if appropriate to investigate perlite’s usability in blended cement production. For this purpose, perlites from two different sources – Izmir and Erzincan - are used as replacement of portland cement clinker with two different percentages: 20% and 30% by weight of total cement. Then for each different composition, materials are ground with some gypsum in order obtain grinding curves for the resultant cements. After obtaining the grinding curves, a total of 22 cements with two different finenesses are produced by intergrinding and separately grinding the materials for each composition. The obtai...

ABSTRACT In a X-ray microcomputed tomography study, active corrosion was induced by galvanostatically corroding steel embedded in cement paste. The results give insight into corrosion product build up, crack formation, leaching of products into the cracks and voids, and differences in morphology of corrosion attack in the case of carbon steel or stainless steel reinforcement. Carbon steel was homogeneously etched away with a homogeneous layer of corrosion products forming at the steel/cement paste interface. For ferritic stainless steel, pits were forming, concentrating the corrosion products locally, which led to more extensive damage on the cement paste cover.

ABSTRACT The present study focuses on identification and micro-structural characterization of the hydration products formed in high-volume fly ash (HVFA)/portland cement (PC) systems using monochromatic scanning x-ray micro-diffraction (μ-SXRD) and SEM-EDS. Pastes with up to 80% fly ash replacement were studied. Phase maps for HVFA samples using μ-SXRD patterns prove that μ-SXRD is an effective method to identify and visualize the distribution of phases in the matrix. μ-SXRD and SEM-EDS analysis shows that the C-S-H formed in HVFA system containing 50% or more of fly ash has a similar structure as C-S-H(I) with comparatively lower Ca/Si ratio than the one produced in PC system. Moreover, coexistence of C-S-H(I) and strätlingite is observed in the system containing 80% of fly ash, confirming that the amount of alumina and silicate phases provided by the fly ash is a major factor for the formation of C-S-H(I) and strätlingite in HVFA system.

ABSTRACT Keyword: Amorphous material (B) X-ray diffraction (B) Alkali–aggregate reaction (B) Elastic moduli (C) The gel formed during alkali–silica reaction (ASR) can lead to cracking and deterioration of a concrete structure. The elastic properties of the ASR gel using X-ray absorption and Brillouin spectroscopy measurements are reported. X-ray absorption was used to determine the density of the gel as a function of pressure, and the result yields an isothermal bulk modulus of 33 ± 2 GPa. Brillouin spectroscopy was applied to measure isentropic bulk (24.9– 34.0 GPa) and shear moduli (8.7–10.1 GPa) of the gel. The range of values obtained is attributed to the variable composition of samples that were collected under field conditions. Results suggested that amorphous silica becomes expanded and compressible as it absorbs water molecules and alkali ions. This could explain high gel migration rates through the complex pore structures in concrete.