Durability Studies at the Portland Cement Association

A new stress analysis and thickness design procedure for jointed concrete pavements was developed. On the basis of Westergaard’s edge stress solution and several prediction models for stress adjustments for a variety of loading and environmental (i.e., thermal curling) conditions, a modified Portland Cement Association (PCA) equivalent stress analysis and thickness design procedure was proposed and implemented in a highly user-friendly, Windows-based program, TKUPAV, for practical trial applications. The proposed approach has been further verified by reproducing results very close to the PCA’s equivalent stresses and fatigue damages using a spreadsheet program and the TKUPAV program. The possible detrimental effect of loading plus daytime curling has been illustrated in a case study, which also indicated that the effect of thermal curling should be considered in the thickness design of concrete pavements.

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Portland clinker with civil construction waste: influence of pellet geometry on the formation of crystalline phases

Ambiente Construído ◽

10.1590/s1678-86212020000400468 ◽

2020 ◽

Vol 20 (4) ◽

pp. 205-223

Author(s):

Fernanda Nepomuceno Costa ◽

Daniel Véras Ribeiro ◽

Cléber Marcos Ribeiro Dias

Keyword(s):

Sustainable Development ◽

Portland Cement ◽

Rietveld Method ◽

Industrial Process ◽

3D Printer ◽

New Materials ◽

X Ray Diffraction ◽

Construction Waste ◽

X Ray ◽

Portland Cement Association

Abstract Efforts to reduce greenhouse gas emissions in the context of sustainable development have intensified, with the development of research aimed at the production of new materials and binders for construction. This article analyzes the influence of pellet geometry in the production of clinkers, with the incorporation of construction waste (CCW). Procedures adapted from the method proposed by Brazilian Portland Cement Association were adopted in studies of laboratory clinkers, in an attempt to simulate the stages of the industrial process. Pellets were prepared with the same formulation, however, with four different geometries: spherical, with diameters of 1 cm, 2 cm and 3 cm, with manual molding, and semi-spherical, with a diameter of 2 cm, using molds of PLA (polylactic acid) printed on a 3D printer to facilitate the molding of the clinkers in a standardized way. Clinkers were characterized mineralogically by x-ray diffraction (XRD) and the Rietveld method was used to quantify the phases. Variations in the quantities of the alite and belite phases were observed depending on the geometry of the pellets, although the same calcination conditions were used. This is probably due to the variation in the surface area (exposure area) and the gradients of the cooling rate.

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Design aids for rectangular reinforced concrete sections under combined bending and axial forces

Canadian Journal of Civil Engineering ◽

10.1139/l88-117 ◽

1988 ◽

Vol 15 (5) ◽

pp. 916-928 ◽

Cited By ~ 1

Author(s):

P. Riva ◽

M. Z. Cohn

Keyword(s):

Reinforced Concrete ◽

Portland Cement ◽

Key Words ◽

Axial Compression ◽

Strength Analysis ◽

Short Columns ◽

Axial Forces ◽

Portland Cement Association

Design interaction diagrams, Pr–Mr, for rectangular reinforced concrete sections under combined bending and axial compression or tension forces in accordance with the current Canadian code are presented. The interest of the note is that the interaction diagrams eliminate the limitations of those in the Canadian Portland Cement Association Handbook. Their format can be extended to other section shapes and reinforcement layouts. Key words: Combined bending, design aids, interaction diagrams, rectangular sections, reinforced concrete, short columns, strength analysis.

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Use of the Water-Ratio Specification on the Portland Cement Association Building

ACI Journal Proceedings ◽

10.14359/15440 ◽

1926 ◽

Vol 22 (2) ◽

Keyword(s):

Portland Cement ◽

Portland Cement Association ◽

Water Ratio

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Análisis comparativo de mezclas suelo cemento modificadas con materiales no biodegradables. Metodología de la portland cement association

Infraestructura Vial ◽

10.15517/iv.v19i33.32918 ◽

2018 ◽

Vol 19 (33) ◽

Author(s):

Sandra Elodia Ospina Lozano ◽

Camilo Andrés Nieves Castro ◽

Adriana María López Velandia

Keyword(s):

Portland Cement ◽

Portland Cement Association

Este artículo presenta el análisis comparativo de investigaciones realizadas en la Universidad de La Salle – Colombia desde el año 2012, referente a mezclas suelo cemento modificadas diseñadas con la metodología de la Portland Cement Association [PCA] (ACI, 1997), y guiadas por el artículo 350 del Instituto Nacional de Vías [Invías] del año 2013, que refiere a las características que debe cumplir una mezcla granular mejorada con cemento para control de calidad en obra, de aplicación nacional en Colombia. Inicialmente se recopila y organiza la información de manera que se identifiquen criterios comparativos de los resultados obtenidos de mezclas suelo cemento modificadas con materiales no biodegradables, como vidrio templado, poliestireno expandido [EPS], tereftalato de polietileno [PET], polietileno de alta densidad [PEHD] y grano de caucho. Enseguida se evaluaron los resultados obtenidos de dicho análisis comparativo, cuyas variaciones en los contenidos óptimos de cemento discrepan de los rangos sugeridos de la PCA, lo que lleva a plantear una discusión sobre la aplicación de esta metodología para mezclas suelo cemento modificadas, proponiendo nuevos rangos de parámetros de control para futuras investigaciones, los cuales servirán como punto de partida para proponer una nueva metodología de diseño en mezclas suelo cemento empleando dichos materiales. Sin embargo, el análisis aquí mostrado evidencia la necesidad de enriquecer con un mayor número de datos las recomendaciones que se presentan, para dar validez soportado en un procesamiento estadístico suficiente.

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