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Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
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Home > Tools > Frequently Asked Questions
Q. What is meant by setting of cement paste or concrete? A. The paste formed when cement is mixed with water remains plastic for a limited time-duration. As time passes, cement hydration (unless inhibited by external factors such as retards or freezing) increases leading to stiffening, setting and hardening. The setting process is arbitrarily divided into stages, time of initial setting and time of final setting, depending on the resistance to penetration by a probe. Before the time of initial setting, it is still possible to disturb the concrete and remix it with little-to-no effect on its final properties. Later revibration can be beneficial, but as the reactions between the cement and water continue, the mass loses its plasticity. At the time of final setting, the concrete has become rigid and fractures rather than flows as increasing stress is applied. References: SP-1(02); ACI Physical Testing of Cement Training Video; The Contractor's Guide to Quality Concrete Construction; ASTM C403; ASTM C191 Topics in Concrete: Cementitious Material; Concrete Fundamentals; Materials
Q. What is meant by setting of cement paste or concrete?
A. The paste formed when cement is mixed with water remains plastic for a limited time-duration. As time passes, cement hydration (unless inhibited by external factors such as retards or freezing) increases leading to stiffening, setting and hardening. The setting process is arbitrarily divided into stages, time of initial setting and time of final setting, depending on the resistance to penetration by a probe. Before the time of initial setting, it is still possible to disturb the concrete and remix it with little-to-no effect on its final properties. Later revibration can be beneficial, but as the reactions between the cement and water continue, the mass loses its plasticity. At the time of final setting, the concrete has become rigid and fractures rather than flows as increasing stress is applied.
References: SP-1(02); ACI Physical Testing of Cement Training Video; The Contractor's Guide to Quality Concrete Construction; ASTM C403; ASTM C191
Topics in Concrete: Cementitious Material; Concrete Fundamentals; Materials
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