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Showing 1 to 20 of 36 for “"air void"”.
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Entrained Air-Void System For Durable Highway Concrete
… heating elements. These units are easily repaired by conventionally trained heating and air conditioning technicians and economically modified using readily available controls. Consequently, proposed factors and modifications to the test method are based on this piece of equipment. Sufficient …
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Developing An Alternative Hardened Concrete Air Void Characterization Method
… characterization method for the hardened air void system in concrete. This study uses ASTM C457, “Standard Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete” as a baseline characterization method and attempts to thoroughly reduce the long …
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Advances in measuring parameters of the air-void system in hardened concrete
… the freezing and thawing resistance of concrete, air bubbles are entrained and distributed evenly and closely. Evaluation of the parameters of the air-void system in hardened concrete is detailed in ASTM C457 “Standard Test Method for Microscopical Determination of Parameters of the Air-Void …
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Analysis of air-void system in hardened concrete from a three-dimensional perspective
… can be greatly enhanced by entrainment of small air bubbles in the cement paste. When the volume and distribution of the entrained air is properly controlled, the microstructure is protected from pressure exerted by freezing water. ASTM C457 “Standard Test Method for Microscopical Determination …
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Determining the Air Void Parameters of Concrete Using Digital Image Analysis of Polarized Light Micrographs
… test has long been a standard used to obtain the air void parameters of concrete materials. These air void parameters provide valuable information that has been linked to the performance of concrete under conditions such as freezing and thawing cycles. The standard test procedure involves linearly …
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Development of image analysis techniques to assist evaluation of both air void structure and aggregate shape factors in concrete
… and durability of concrete is brought about by voids left within the concrete once it has hardened. These voids can arise from a number of sources both intentional, in the case of air-entrained voids introduced by admixtures batched to provide a structure that can withstand frost attack and …
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EFFECT OF CRACK-REDUCING TECHNOLOGIES AND SUPPLEMENTARY CEMENTITIOUS MATERIALS ON SETTLEMENT CRACKING OF PLASTIC CONCRETE AND DURABILITY PERFORMANCE OF HARDENED CONCRETE
… NQ 2621-900 Annex B, and characteristics of the air-void system, obtained following ASTM C457. The research also examined the correlation between air-void characteristics, compressive strength, freeze-thaw durability, and scaling resistance for the mixtures. All mixtures experienced increased …
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Super Absorbent Polymers (SAPs) as physical air entrainment in cement mortars
… for using SAPs as a mechanism for physical air entrainment. Mixtures were produced using various quantities of either dry or pre-saturated SAP to replace conventional air entrainment agents (AEAs) along with a conventionally air-entrained control. One additional mixture used lightweight fine …
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Characterization of High Porosity Drainage Layer Materials for M-E Pavement Design
… treated permeable base mixture of different air void contents has also been quantified in laboratory. Numerical simulations are conducted to investigate the location effects and the contribution of the drainage layer as a structural component within pavement. The optimal air void content of …
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Hot Mix Asphalt Permeability: Tester Size Effects and Anisotropy
… and analyze. A series of samples with different air void contents were used to observe how the ratio of vertical to horizontal permeability changes with air void content. The second goal was to develop a modified field permeameter to study the water-pavement contact area effect on field …
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Durability of Cementitious Materials in Arctic Regions: Investigating Freeze-Thaw Damage and Chloride Ingress Diffusion Mechanisms
… cementitious material durability, optimizes repair techniques for long-term performance, and develops a real-time monitoring technique to track pore water movement within the concrete microstructure and its impact on microstructural cracking. First, this dissertation investigated the combined …
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Microstructure characterization of foamed cement and concrete
… is a major durability issue in cold climates. Air-entraining admixtures are used to create a network of fine bubbles that enhance frost resistance. Experience has shown that fresh air content alone cannot predict the effectiveness of the entrained air system. Instead, parameters such as bubble …
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Evaluation of Troxler 3241-C nuclear asphalt content gauge used for Marshall specimens
… considered: aggregate type, aggregate gradation, air-void content, moisture content in specimens, asphalt cement content, and total specimen weight. Different calibration models were developed for different bituminous mixtures.
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Effect of specimen geometry and test configuration on the fracture process zone for asphalt materials
… notch length, specimen thickness, loading rate, air void content, and asphalt binder on I-FIT global results and microstructural response. Multiple samples with varying notch lengths, thicknesses, and loading rates were evaluated to observe the effect of the test parameters. Then, samples with …
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Modelling the Flushing Mechanism of Thin Flexible Surface Pavements
… flushing, focusing on the relationship between air voids and flushing initiation. Additionally, the research aimed to develop a pavement deterioration model to predict the initiation and progression of flushing on chip seal pavements. Mechanical testing was conducted on cores obtained from …
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ANALYTICAL MODELING OF RUTTING POTENTIAL OF ASPHALT MIXES USING HAMBURG WHEEL TRACKING DEVICE
… studied parameters). In addition, the effect of air void contents was studied showing insignificant sensitivity for the studied parameters. Finally, the rutting behavior of AC mixtures under the different conditions mentioned above promisingly correlated with the Weibull function.
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Evaluating CEN/TS 12390-9 To Assess Concrete for UK Freeze-Thaw Exposure Conditions
… and CEM II/A-L (limestone) cements, both non-air and air entrained, with different target strengths (20-60 MPa for non-air entrained and 20-50 MPa for air entrained) and a target air content of 4.5%, in accordance with BS 8500. BS EN 197-1 outlines the maximum addition contents that can be …
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Laboratory evaluation of asphalt-portland cement concrete composite
… Composite (APCCC) is a hot-mix asphalt with air voids in the range of 25 to 30 percent which is later filled with resin modified cement grout. The resin modified cement grout consists of portland cement, fly ash, sand, water, and prosalvia (PL7) additive. The objective of the research was …
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Prediction of asphalt concrete pavement density from processing ground-penetrating radar compaction data
… change during AC pavement compaction using air-coupled antennas. However, issues, including surface moisture effect due to water spray during compaction, vibration effect during continuous GPR survey, and signal processing complexity, may hinder AC density prediction accuracy. This study …
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Air entrainment in vertical dropshafts
… an investigation into the phenomenon of air entrainment in vertical dropshafts conveying water from a high level to a lower level. The study initially commenced with hydraulic tests on scale models of a vortex-entry dropshaft arrangement. This subsequently expanded into a more detailed …
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