Question

Problems 1a)-1) Provide concise answers to the following. 1a) To what stress level (percent off) is the stress strain relationship for concrete considered to be approximately linear? (1 pt) 1b) Why is the mean strength of concrete received from a ready-mix plant greater than the design strength, fc? (2 pts) 1c) Which type of cement is used to achieve high early strength? (1 pt) 1d) Give three of the basic assumptions that are made in the design or analysis of a reinforced concrete beam in flexure. (1.5 pts) 1e) Does concrete shrink more in a humid or a dry environment? Why? (2 pts) 11) What are three advantages to building with reinforced concrete? (1.5 pts) 1h) What is a tension controlled failure and why is it considered to be desirable? (3 pts) 11) What two important characteristics allow the Whitney stress block to give estimates of strength similar to a more realistic parabolic stress-strain relationship for concrete? (2 pts)

Answer 1

Ano 1a) All concretes present Very Similar stress- Sali lesne Zegardless of the Reyled aggregate sod. Geplacement datio The Shape is linear to 0.40fc, and then it becomes parabolic. Stress (6) 0401 Straum & As 1b) Ia a Ready Mix concreto the Cementions Materials are acoled on cloleineetóc basis iu. Required quantities and the addition of Adnonture along with evler Pusseoses the coolbóbility of concrete. Then rinung of materials with increased wolkeability give more strought to Rmc than design min. An IC) Rapid Hardening Cement is also called as fligh Carly strenght cement. The prime difference between Rote Raped Hardening Cement and ope is the time content. This Rhe is burnt under high temperatures than Opc. The b 3 days Streught of Ric is aqual to & day streught of OPG A

Aid) Doumptions made for Desson of Beam in ferme a plain sections normal to the anis Gempur plane after bending The marimum shoiu ei concrete at the outermost compression fibre is taken as 0.0035 Pr bandung, bending. © The Jelationship bekveen Sliess Strain distubulion in concrete is assume to be parabolic.