scholarly journals Geochemistry, Mineralogy and Textural Properties of the Lower Globigerina Limestone Used in the Built Heritage

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 740
Author(s):  
Lino Bianco
Keyword(s):  
Textural Properties ◽  
Clay Content ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Insoluble Residue ◽  
Neolithic Period ◽  
The Matrix ◽  
Mechanical Bonding ◽  
Insight Into

The Lower Globigerina Limestone Member, the oldest member of the Globigerina Limestone Formation, outcrops over most of the Maltese archipelago, notably Malta. It has provided the islands’ main building material since the Neolithic period. This paper makes available a corpus of findings relating to the geochemistry, mineralogy and textural properties of this limestone—mostly unpublished and undertaken nearly three decades ago—which provide a useful source to understand its behavior. Bulk chemistry and mineralogy showed that non-carbonate and clay content is higher in limestone of inferior quality. Textural analyses gave insight into the fabric of the matrix, including inter- and intra-particle porosity. These analyses were supplemented by an array of petrophysical tests, including color (a parameter which has a correlation with density and Fe2O3 content), ultrasonic pulse velocity and compressive strength. The findings not only give insight into the composition of the limestone, using insoluble residue content of ≥5% as the threshold of inferior quality lithotype, but provided an insight into the physico-mechanical bonding present, a characteristic which has a bearing on the deterioration of this limestone.

Relationship between methylene blue values of concrete aggregate fines and some concrete properties

2008 ◽  
Vol 35 (4) ◽  
pp. 379-383 ◽  
Author(s):  
İlker Bekir Topçu ◽  
Abdullah Demir
Keyword(s):  
Methylene Blue ◽  
Clay Content ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Concrete Properties ◽  
Ready Mixed Concrete ◽  
Methylene Blue Value

The fine granular structure and surface activity of clay minerals increase the amount of mixing water needed to provide workability in concrete. Even when the microfine material percentage in fine aggregate is low, the methylene blue value of the fine aggregate increases when materials of clay origin are present. In this study, methylene blue values were determined in fine aggregate samples used to produce ready-mixed concrete. Samples were taken from four different aggregate quarries, and relationships between methylene blue values of the concrete samples produced with these aggregates and some of their properties were investigated. Tests were done to determine the quality of microfine material (i.e., passing 0.063 mm sieve). Slump, ultrasonic pulse velocity, compressive strength, and surface abrasion resistance tests were performed on concretes made with these aggregate fines. It is shown that clay content, as indicated by the methylene blue value test, affects the concrete properties, but the microfine material percentage does not give any hint about clay content.

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.

scholarly journals Mechanical Characterisation and Shrinkage of Thermoactivated Recycled Cement Concrete

2021 ◽  
Vol 11 (6) ◽  
pp. 2454
Author(s):  
Sofia Real ◽  
José Alexandre Bogas ◽  
Ana Carriço ◽  
Susana Hu
Keyword(s):  
Mechanical Strength ◽  
Elasticity Modulus ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Concrete ◽  
Supplementary Cementitious Material ◽  
Mechanical Characterisation ◽  
Shrinkage Behaviour ◽  
Binder Ratio

This paper investigates the mechanical and shrinkage behaviour of concrete with recycled cement (RC) thermoactivated from waste cement paste and waste concrete. Overall, compared to ordinary Portland cement (OPC), for the same water/binder ratio, the mechanical strength and ultrasonic pulse velocity were not significantly influenced by the incorporation of RC. The elasticity modulus decreased with the addition of RC and the shrinkage tended to increase at high RC content. The incorporation of up to 15% RC allowed the production of workable concrete with identical shrinkage and similar to higher mechanical strength than concrete with only OPC. RC proved to be a very promising more eco-efficient supplementary cementitious material.

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