In contrast to modern concrete structures, the concrete used in Roman buildings was usually covered with brick or stone. Concrete is a composite material composed of coarse aggregate bonded together with a fluid cement that hardens over time. Most concretes used are lime-based concretes such as Portland cement concrete or concretes made with other hydraulic cements, such as ciment fondu.
https://en.wikipedia.org/wiki/Concrete
Actually, ASTM recommends cylindrical samples for this purpose. A test result is the average of at least two standard-cured strength specimens made from the same concrete sample and tested at the same age. In most cases strength requirements for concrete are at an age of 28 days. Richard · 1 year ago.
https://answers.yahoo.com/question/index?qid=20091023031907AAmgpak
ARCH 631 Note Set 10.1 F2013abn. 3. Reinforced concrete is a composite material, and the average density is considered to be 150 lb/ft3. It has the properties that it will creep (deformation with long term load) and shrink (a result of. hydration) that must be considered. Plane sections of composite materials can still.
http://faculty.arch.tamu.edu/media/cms_page_media/4348/NS10-1concrete.pdf
Aggregate consists of large chunks of material in a concrete mix, generally a coarse gravel or crushed rocks such as limestone, or granite, along with finer materials such as sand. Cement, most commonly Portland cement, is associated with the general term concrete..
https://en.wikipedia.org/wiki/Concrete
Many writers struggle with composition because they do not have a clear sense of the function of concrete detail and commentary. It is important to be explicit with students about how these components of the research report operate in the assignment.
http://ctfd.sfsu.edu/teaching-practices/concrete-detail-and-commentary
The concrete detail in the second passage personifies nature and gives the reader a greater sense of doom than the first passage. The function is to communicate to the reader the seriousness of the event and to ensure the reader sees the threat from a certain point of view. In a research report, concrete detail speaks to the evidence surrounding an assertion.
http://ctfd.sfsu.edu/teaching-practices/concrete-detail-and-commentary
1 9.1 APPLICATION. 9.1.1 General. 2  The specifications of this section are intended for. design of prestressed concrete bridge members. Mem­. bers designed as reinforced concrete, except for a per­. centage of tensile steel stressed to improve service behav­. ior, shall conform to the applicable specifications of. Section 8.
http://www.dot.ca.gov/hq/esc/techpubs/manual/bridgemanuals/bridge-design-specifications/page/section9.pdf
A rectangular beam which must carry service live load of 2.5 kips/ft and a calculated dead load of 1.1. kips/fton an 18 ftsimplespan islimited in crosssection forarchitecturalreasonsto 10 inches in width. and 20 inches in total depth.
http://www.ce.memphis.edu/4135/PDF/Notes/Chap_6_4__hw_6.pdf
f’c Concrete Compressive Strength. Definition: f’c is the specified compressive strength of concrete using standard cylinders of six inches diameter and twelve inches height. Usually this is prescribed at the age of 28 days. The word specified means here usually a set of guidelines meeting the minimum requirements.
http://www.engineeringintro.com/concrete/what-is-fc-concrete/
The Concrete strength is calculated by dividing the maximum load at failure by the average cross sectional area. Concrete compressive strength requirements can vary from 2500 psi (17 MPa) for residential concrete to 4000 psi (28 MPa) and higher in commercial structures.
https://answers.yahoo.com/question/index?qid=20091023031907AAmgpak
what is f'c in concrete
f’c is the specified compressive strength of concrete using standard cylinders of six inches diameter and twelve inches height.