Concrete Compressive Strength under Changing Environmental Conditions during Placement Processes

Ambroziak, Andrzej; Ziółkowski, Patryk

doi:10.3390/ma13204577

Cited by 20 publications

(16 citation statements)

References 24 publications

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“…Additionally, a wide scatter in compressive strength may be affected by the proportion of cement and aggregate (sand to gravel volumetric ratios) for the old concrete mix preparation. Concrete strength may also be affected by different climatic conditions in the course of placement [ 42 ]. The specimens were crushed or got separated along a slanted surface and columnar vertical cracking through both ends with no well-formed cones was observed.…”

Section: Laboratory Test Results and Discussionmentioning

confidence: 99%

A 95-Year-Old Concrete Arch Bridge: From Materials Characterization to Structural Analysis

Ambroziak

Malinowski

2021

Materials

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The structural analysis of a 95-year-old concrete arch bridge located in Jagodnik (Poland) is performed in this paper, in order to check its behavior under today’s traffic loads. The mechanical properties of both the concrete and the reinforcement are investigated by testing cores and bar stubs extracted from the bridge. Structural analysis confirms that the bridge meets today’s load requirements in terms of bearing capacity, serviceability state, and that the adopted structural improvements (a new deck slab on top of the existing structure and a layer of mortar to protect the surface of the old concrete) are effective. In this way, the 95-year-old arch bridge was given a new life. The structural improvements show how combining numerical modelling and laboratory tests can contribute to the preservation of an old—though fairly simple—and valuable structure, otherwise destined to demolition, with both environmental and economic benefits.

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Section: Laboratory Test Results and Discussionmentioning

confidence: 99%

A 95-Year-Old Concrete Arch Bridge: From Materials Characterization to Structural Analysis

Ambroziak

Malinowski

2021

Materials

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“…Therefore, the properties of concrete mixes are often oversized, which can lead to very unfavorable phenomena. For example, increasing concrete strength more than the designed value may cause changes in the structure’s stiffness and lead to so-called concrete superstrength [ 23 ]. Predicting the properties of concrete is a complex issue, while most of the solutions used in engineering practice are approximate methods that, especially in recent years, due to the rapid development of materials engineering, have become outdated.…”

Section: Discussionmentioning

confidence: 99%

“…Designing a mix with the improper specification can have many serious consequences; therefore, concrete mix producers fearing failure to meet the appropriate criteria often deliberately augment its parameters beyond designed values. This leads to the phenomenon called “concrete superstrength”, which on the surface may seem beneficial, because, for example, in a case of concrete compressive strength, the strength of concrete is higher; however, the disturbed stiffness of the structure may cause the structure to behave differently than envisaged by the designer [ 23 ].…”

Section: Concrete MIX Design and Machine Learningmentioning

confidence: 99%

Model-Based Adaptive Machine Learning Approach in Concrete Mix Design

2021

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Concrete mix design is one of the most critical issues in concrete technology. This process aims to create a concrete mix which helps deliver concrete with desired features and quality. Contemporary requirements for concrete concern not only its structural properties, but also increasingly its production process and environmental friendliness, forcing concrete producers to use both chemically and technologically complex concrete mixtures. The concrete mix design methods currently used in engineering practice are joint analytical and laboratory procedures derived from the Three Equation Method and do not perform well enough for the needs of modern concrete technology. This often causes difficulties in predicting the final properties of the designed mix and leads to precautionary oversizing of concrete properties for fear of not providing the required parameters. A new approach that would make it possible to predict the newly designed concrete mix properties is highly desirable. The answer to this challenge can be methods based on machine learning, which have been intensively developed in recent years, especially in predicting concrete compressive strength. Machine learning-based methods have been more or less successful in predicting concrete compressive strength, but they do not reflect well the variability that characterises the currently used concrete mixes. A new adaptive solution that allows estimating concrete compressive strength on the basis of the concrete mix main ingredient composition by including two observations for a given batch of concrete is proposed herein. In presented study, a machine learning model was built with a deep neural network architecture, trained on an extensive database of concrete recipes, and translated into a mathematical formula. Testing on four concrete mix recipes was performed, which were calculated according to contemporary design methods (Bolomey and Fuller method), and a comparative analysis was conducted. It was found out that the new algorithm performs significantly better than that without adaptive features trained on the same dataset. The presented algorithm can be used as a concrete strength checking tool for the concrete mix design process.

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“…Compressive strength data higher than the designed value could not be beneficial from a structural viewpoint because undue stiffness might cause an inadequate redistribution of internal forces and exhibit greater than projected stress and deflection [37].…”

Section: Compressive Strengthmentioning

confidence: 99%

Performance of Ground Granulated Blast-Furnace Slag and Coal Fly Ash Ternary Portland Cements Exposed to Natural Carbonation

et al. 2021

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Ternary Portland cements are new cementitious materials that contain different amounts of cement replacements. Ternary Portland cements composed of granulated blast-furnace slag (GBFS), coal fly ash (CFA), and clinker (K) can afford some environmental advantages by lowering the Portland cement clinker use. Accordingly, this is an opportunity to reduce carbon dioxide emissions and achieve net-zero carbon emissions by 2050. Furthermore, GBFS and CFA possess pozzolanic properties and enhance the mechanical strength and durability at later ages. Compressive strength and natural carbonation tests were performed in mortar and concrete. Cement-based materials made with GBFS and/or CFA presented a delay in the compressive strength development. In addition, they exhibited lower carbonation resistance than that of mortar and concrete made with plain Portland cements. Concrete reinforcement remains passive in common conditions; however, it could be corroded if the concrete pore solution pH drops due to the carbonation process. Service life estimation was performed for the ternary cements regarding the carbonation process. This information can be useful to material and civil engineers in designing concretes made with these ternary cements.

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Concrete Compressive Strength under Changing Environmental Conditions during Placement Processes

Cited by 20 publications

References 24 publications

A 95-Year-Old Concrete Arch Bridge: From Materials Characterization to Structural Analysis

A 95-Year-Old Concrete Arch Bridge: From Materials Characterization to Structural Analysis

Model-Based Adaptive Machine Learning Approach in Concrete Mix Design

Performance of Ground Granulated Blast-Furnace Slag and Coal Fly Ash Ternary Portland Cements Exposed to Natural Carbonation

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