Materials for Civil and Construction Engineers (2nd Edition)
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ISBN: 9781292154411
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Chapter 7, Problem 7.39QP
To evaluate the effect of a certain admixture on the flexure strength of concrete, two mixes were prepared, one without admixture and one with admixture. Three beams were prepared of each mix. All the beams had a cross section of 4 in. × 4 in. and a span of 12 in. The third-point loading flexure strength test was performed on each beam after 7 days of curing. The loads at failure of the beams without admixture were 6044, 5071, and 5934 lb, while the loads at failure of beams with admixture were 7299, 7305, and 6983. Determine:
- a. The modulus of rupture of each beam in psi.
- b. The average moduli of rupture of the beams without and with admixture.
- c. The percent of increase of the average modulus of rupture due to adding the admixture.
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Chapter 7 Solutions
Materials for Civil and Construction Engineers (2nd Edition)
Ch. 7 - The design engineer specifies a concrete strength...Ch. 7 - A project specifies a concrete strength of 24.1...Ch. 7 - A project specifies a concrete strength of at...Ch. 7 - What is your recommendation for the maximum size...Ch. 7 - A concrete mix with a 3-in. slump, w/c ratio of...Ch. 7 - Prob. 7.6QPCh. 7 - You are working on a concrete mix design that...Ch. 7 - Design the concrete mix according to the following...Ch. 7 - Design the concrete mix according to the following...Ch. 7 - The design of a concrete mix requires 1173 kg/m3...
Ch. 7 - Prob. 7.11QPCh. 7 - Prob. 7.12QPCh. 7 - Students in the materials lab mixed concrete with...Ch. 7 - Students in the materials lab mixed concrete with...Ch. 7 - Why is it necessary to measure the air content of...Ch. 7 - What do we mean by curing concrete? What will...Ch. 7 - Discuss five different methods of concrete curing.Ch. 7 - Draw a graph showing the typical relation between...Ch. 7 - Why is extra water harmful to fresh concrete, but...Ch. 7 - Discuss the change in volume of concrete at early...Ch. 7 - Discuss the creep response of concrete structures....Ch. 7 - Prob. 7.22QPCh. 7 - On one graph, draw a sketch showing the typical...Ch. 7 - Using Figure 7.34, a. Determine the ultimate...Ch. 7 - Three concrete mixes with the same ingredients,...Ch. 7 - Three concrete mixes with the same ingredients,...Ch. 7 - Three 100 mm 200 mm concrete cylinders with water...Ch. 7 - Students in the materials class prepared three 4 ...Ch. 7 - Three 150 mm 300 mm concrete cylinders with water...Ch. 7 - Three 6 in. 12 in. concrete cylinders with water...Ch. 7 - A normal-weight concrete has an average...Ch. 7 - Discuss the significance of the compressive...Ch. 7 - What is the standard size of PCC specimens to be...Ch. 7 - Prob. 7.34QPCh. 7 - What is the purpose of performing the flexure test...Ch. 7 - What are the advantages of using a third-point...Ch. 7 - Consider a standard flexural strength specimen of...Ch. 7 - To evaluate the effect of a certain admixture on...Ch. 7 - To evaluate the effect of a certain admixture on...Ch. 7 - Prob. 7.40QPCh. 7 - Prob. 7.41QPCh. 7 - A normal-weight concrete has an average...Ch. 7 - Three batches of concrete were prepared using the...Ch. 7 - Three batches of concrete were prepared using the...Ch. 7 - Prob. 7.45QPCh. 7 - Prob. 7.46QPCh. 7 - Discuss two nondestructive tests to be performed...Ch. 7 - Discuss the concept of concrete maturity meters.Ch. 7 - Discuss four alternatives that increase the use...Ch. 7 - What is self-consolidating concrete? How are its...Ch. 7 - Prob. 7.51QPCh. 7 - Two 6 in. 12 in. concrete cylinders with randomly...Ch. 7 - Discuss the concept of high-performance concrete....Ch. 7 - Comparing PCC with mild steel, answer the...Ch. 7 - Prob. 7.55QP
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