Ebook Materials for civil and construction engineers (4/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Materials for civil and construction engineers (4/E): Part 2
Ebook Materials for civil and construction engineers (4/E): Part 2
www.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2nt concrete and the proportions of the components used in it. The quality of the concrete is governed by the chemical composition of the portland cement, hydralion and development of the imanoslnicliire, admixtures, and aggHĩgalo characteristics, rhe quality is strongly affix Jed by placement, conso Ebook Materials for civil and construction engineers (4/E): Part 2lidation, and curing, as well.How a concrete structure performs throughout ils service life is largely determined by the methods of mixing, transportiEbook Materials for civil and construction engineers (4/E): Part 2
ng, placing, and (airing the concrete in the field. In fact, the ingredients of a "good" concrete may be the same as those of a "bad" concrete. The diwww.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2made in concrete technology in the past few decades, concrete Kill be used in many more applications. Civil and const ruction engineers should be aware of the alternatives Io conventional concrete, such as lightweight concrete, high strength concrete, polymer concrete, fiber reinforced concrete, and Ebook Materials for civil and construction engineers (4/E): Part 2 roller com pacled concrete. Before using these alternatives Io conventional concrete, the engineer needs to study them, and their costs, in detail. TEbook Materials for civil and construction engineers (4/E): Part 2
ins chapter covers basic principles of conventional portland cement concrete, its proportioning, mixing and handling. Cluing. and testing. Alternativewww.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2ities involved in the construction process of concrete structures.7.1Proportioning of Concrete MixesThe properties of concrete depend on the mix proportions and the placing and cur ing methods. Designers generally specify or assume a certain strength or modulus of elasticity of the concrete when det Ebook Materials for civil and construction engineers (4/E): Part 2ermining structural dimensions. The materials engineer is responsible for assuring that the concrete is properly proportioned, mixed, placed, and cureEbook Materials for civil and construction engineers (4/E): Part 2
d so as to have the properties specified by the designer.www.downloadslide.net288 Chapter 7 Portland Cement ConcreteI.Mix Design (Proportioning)II.Triwww.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2VII.Vibrating (Consolidating) Initial SetVIII.Finishing-—................................Final SetIX.CuringX.MaintenanceFIGURE 7.1 Order of operations for concrete.The proportioning of the concrete mix affects its properties in both the plastic and solid states. During the plastic state, the materia Ebook Materials for civil and construction engineers (4/E): Part 2ls engineer is concerned with the workability and finishing characteristics of the concrete. Properties of the hardened concrete important to the mateEbook Materials for civil and construction engineers (4/E): Part 2
rials engineer are the strength, modulus of elasticity, durability, and porosity. Slnuiglli is generally lilts controlling design factor. Unless otherwww.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2 0.30-111 cylinders lesled in compression after curing for 28 days.The PCA specifies three qualities required of properly proportioned concrete mixtures (Kosmatka et al.. 2011):1acceptable workability of freshly mixed concrete2durability, strength, and uniform appearance of hardened concrete3economy Ebook Materials for civil and construction engineers (4/E): Part 2In order Io achieve these characteristics, the materials engineer must determine the proportions of cement, water, fine and coarse aggregates, and theEbook Materials for civil and construction engineers (4/E): Part 2
use of admix tines. Several mix design methods have been developed over the years, ranging from an arbitrary volume method (1:2:3 cement: sand: coarswww.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2ively simple techniques for estimating mix proportions, using an assumed or known unit weight of concrete. The absolute volume method uses the specific gravity of each ingredient to calculate the unit volume each will occupy in a unit volume of concrete. The absolute volume method is more accurate t Ebook Materials for civil and construction engineers (4/E): Part 2han the weight method. The mix design process for tile weight and absolute volume methods differs only in how the amount of fine aggregates is determiEbook Materials for civil and construction engineers (4/E): Part 2
ned.www.downloadslide.netSection 7.1 Proportioning of Concrete Mixes 2897.1.1 Basic Steps for Weight and Absolute Volume MethodsThe basic steps requirwww.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemen Ebook Materials for civil and construction engineers (4/E): Part 2ements.www.downloadslide.netCHAPTERPORTLAND CEMENTCONCRETECivil and construction engineers are directly responsible for the quality control of portland cemenGọi ngay
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