scholarly journals Multi-Analysis Characterisation of a Vernacular House in Doha (Qatar): Petrography and Petrophysics of its Construction Materials

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 241
Author(s):  
Freire-Lista ◽  
Kahraman ◽  
Carter
Keyword(s):  
Analytical Data ◽  
Construction Materials ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Effective Porosity ◽  
City Centre ◽  
X Ray ◽  
Aesthetic Characteristics ◽  
Original Construction

This study characterises the original construction materials (building stones and mortars) of a collapsed two-storey colonnaded structure in the Ismail Mandani house, located in the old city centre of Doha (Qatar). Results were drawn based on interpretation and integration of historical, in situ observations and analytical data. The mortars and stones were characterised following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and elemental analysis (handheld X-ray fluorescence) of samples. Moreover, hydric properties, ultrasonic pulse velocity and colour of representative samples of the house were studied. The results revealed the use of two types of stones and three different types of gypsum mortars. The original construction materials came from nearby coastal stones. Gypsum of the most used mortar had a calcination temperature between 120 and 160 °C and its colour was produced by lumps with higher Fe content. The materials’ effective porosity and water absorption were high, and their ultrasonic pulse velocity was low. These petrophysical results indicated they had low quality for construction purposes. The composition and colour of the original construction materials were quantified, which will allow the reproduction of their aesthetic characteristics and improvement of their quality in future reconstruction works.

scholarly journals Multi-Analytical Characterization of Corvins’ Castle—Deserted Tower. Construction Materials and Conservation Tests

Heritage ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 941-964
Author(s):  
Rodica Mariana Ion ◽  
Lorena Iancu ◽  
Madalina Elena David ◽  
Ramona Marina Grigorescu ◽  
Bogdan Trica ◽  
...  
Keyword(s):  
Analytical Data ◽  
Construction Materials ◽  
Morphological Characterization ◽  
Absorption Capacity ◽  
Effective Porosity ◽  
X Ray ◽  
Peeling Test ◽  
Architectural Monument ◽  
Physico Chemical ◽  
Macroscopic Observation

The aim of this paper is to analyze the construction materials (mortars) of an architectural monument (Deserted Tower (Lilly Tower) from Corvins’ Castle, Romania). The mortars were characterized following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and elemental analysis (X-ray fluorescence), hydric properties, and color of representative samples of the monument. The results revealed the use of gypsum mortars (produced by lumps with higher Fe content), with minor concentrations of crystalline dolomites of the Southern Carpathians, calcite, and quartz. The materials’ effective porosity and their water absorption capacity were high. A possible solution to consolidate the damaged area with some consolidation products (hydroxyapatite carbonate and its derivatives with Ag and Sr) was investigated, too. The interactions between the mortar’s specimens and the effectiveness of the consolidation treatments were evaluated by physico-chemical analyses (molecular structure by X-ray powder diffraction (XRPD), wavelength dispersive X-ray fluorescence (WDXRF), dynamic light scattering (DLS)), morphological characterization by microscopic techniques as SEM-EDS, TEM, and physical and mechanical investigations (peeling test and compressive strength). Results were drawn based on historical, in situ observations, and analytical data, and put into evidence the composition, high weathering degree, and the possibility to surface consolidate with Sr-CHAp.

An investigation on the properties of woodcrete exposed to high temperature

2020 ◽  
Vol 11 (4) ◽  
pp. 105
Author(s):  
Mehmet Canbaz ◽  
İlkay Kara ◽  
İlker Bekir Topçu
Keyword(s):  
High Temperature ◽  
Temperature Effect ◽  
Construction Materials ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Unit Weight ◽  
Wood Composites ◽  
Cement Ratio ◽  
High Temperature Effect

By combining wood wastes with various binders, construction materials can be produced. These materials can be used in non-bearing parts such as wall block, insulation panel. In this study, prismatic specimens were taken from the mixtures produced considering the chip-cement ratio as 0.25, 0.5 and 1. The unit weight, ultrasonic pulse velocity, bending and compressive strengths of the specimens were determined by using the results of the experiments on these specimens. In addition, specimens were kept at 200 and 400°C for 3 hours in order to determine its behavior under high temperature, which is one of the most important problems for wood composites. With the experiments carried out on the cooled specimens, weight and strength losses, changes in ultrasonic pulse velocity were examined. As a result of the study, while determining that the chip-cement ratio can be used as 1, it is recommended to use the chip-cement ratio up to 0.5 when the high temperature effect is taken into consideration.

Mechanical and Thermal Performances of Eco-Friendly Mortar Containing Recycled PET As Partial Sand Replacement

2021 ◽  
Author(s):  
Nacer Akkouri ◽  
Oumaima Bourzik ◽  
Khadija Baba ◽  
Bassam Tayeh
Keyword(s):  
Thermal Conductivity ◽  
Energy Efficient ◽  
Mechanical Performance ◽  
Construction Materials ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Raw Material ◽  
Recycled Pet ◽  
Potential Use

Abstract Plastic has become one of the most widely manufactured materials in the world and an indispensable part of everyday life. However, a large amount of plastic waste needs to be recycled to protect the environment. One way of recycling is to use such waste as a raw material substitute. This paper evaluates the thermal and mechanical performance of eco-friendly mortars containing 0%, 5%, 10%, 15% and 20% recycled polyethylene terephthalate (PET) particles as partial replacements for sand. Several experiments were conducted to evaluate the thermal properties (i.e. thermal conductivity, thermal diffusivity and heat capacity), compressive strength, density, workability and ultrasonic pulse velocity of these mortars. Results show that replacing sand with recycled PET in cement-based mortars reduces their thermal conductivity, thereby highlighting the potential use of these mortars as energy-efficient and environmentally friendly construction materials.

scholarly journals Effects of plasticizer and antifreeze on concrete at elevated temperatures and different cooling regimes

2020 ◽  
Vol 19 (3) ◽  
pp. 347-357
Author(s):  
İlknur Bekem Kara ◽  
◽  
Metin Arslan ◽  
Keyword(s):  
Elevated Temperatures ◽  
Strength Loss ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Concrete Mixtures ◽  
Main Components

In recent years, chemical admixtures have become one of the main components of concrete alongside aggregate, cement and water. In this study, the plasticizer and the antifreeze were used. The concrete specimens (the reference concrete without an admixture, concrete with plasticizer, concrete with antifreeze and concrete with plasticizer+antifreeze) were exposed to elevated temperatures (200, 400, 550 and 700 ºC) and cooling via air and water. Water absorption, ultrasonic pulse velocity and compressive strength tests were performed on the specimens. The concrete specimens were also analyzed using X-ray diffraction. The test results indicated that at the temperatures of 550 and 700 ºC and against both of the cooling regimes the plasticizer+antifreeze concrete showed a maximum strength loss. When the air cooled specimens were examined, the lowest strength loss was this obtained for reference concrete at 550 and 700 ºC. The lowest strength loss at these temperatures for the water cooled specimens was observed in the concrete with antifreeze. After being exposed to 700 ºC and the cooling regimes, no portlandite peaks were observed in the concrete mixtures was when they were compared at with the control specimen exposed to 20 ºC in the X-ray diffraction analysis.

scholarly journals An An Analysis of Crystalline Admixtures in Terms of Their Influence on the Resistance of Cementitious Composites to Aggressive Environments

2020 ◽  
Author(s):  
Ámos Dufka ◽  
Nikol Žižková ◽  
Jiří Brožovský
Keyword(s):  
Computed Tomography ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Mechanical Tests ◽  
Pulse Velocity ◽  
Cementitious Composites ◽  
Reference Laboratory ◽  
Chemical Analyses ◽  
X Ray ◽  
Physical Chemical

This paper describes the influence of crystalline admixtures on the chemical resistance of cement composites exposed to aggressive environments. The effect of the crystalline admixtures was determined by a series of physical-mechanical and innovative physical-chemical methods. Specifically, this concerned the measurement of flexural strength, compressive strength, determination of the dynamic modulus of elasticity by the ultrasonic pulse velocity test, and an analysis of the internal structure by mercury intrusion porosimetry and x-ray computed tomography. Physical-chemical analyses were also performed; namely an x-ray diffraction analysis to determine the mineralogical composition and electron microscopy to examine the microstructure. The use of non-destructive testing methods (ultrasonic pulse velocity test and computed tomography) made it possible to compare the properties of the same specimens for 16 months. The specimens were stored in reference laboratory conditions, a sodium sulphate solution and an ammonium chloride solution. The physical-mechanical tests and physical-chemical analyses clearly showed the benefit that crystalline admixtures have for the resistance of cementitious composites attacked by chemically aggressive solutions without affecting the fresh-mixture rheology or decreasing the strength of the composites.

PENGKAJIAN KEKUATAN BETON STRUKTUR JEMBATAN PASCA KEBAKARAN

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Strength Assessment ◽  
Concrete Testing

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.

scholarly journals Correlation between Uniaxial Compression Test and Ultrasonic Pulse Rate in Cement with Different Pozzolanic Additions

2021 ◽  
Vol 11 (9) ◽  
pp. 3747
Author(s):  
Leticia Presa ◽  
Jorge L. Costafreda ◽  
Domingo Alfonso Martín
Keyword(s):  
Compression Test ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Uniaxial Compression Test ◽  
Unconfined Compression Test ◽  
Pozzolanic Cement ◽  
The Relationship ◽  
Compression Resistance

This work aims to study the relationship between the compression resistance and velocity from ultrasonic pulses in samples of mortars with 25% of pozzolanic content. Pozzolanic cement is a low-priced sustainable material that can reduce costs and CO2 emissions that are produced in the manufacturing of cement from the calcination of calcium carbonate. Using ultrasonic pulse velocity (UPV) to estimate the compressive resistance of mortars with pozzolanic content reduces costs when evaluating the quality of structures built with this material since it is not required to perform an unconfined compression test. The objective of this study is to establish a correlation in order to estimate the compression resistance of this material from its ultrasonic pulse velocity. For this purpose, we studied a total of 16 cement samples, including those with additions of pozzolanic content with different compositions and a sample without any additions. The results obtained show the mentioned correlation, which establishes a basis for research with a higher number of samples to ascertain if it holds true at greater curing ages.

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