Materials for Civil and Construction Engineers (2nd Edition)
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ISBN: 9781292154411
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Chapter 7, Problem 7.22QP
To determine
The effect of water-cement ratio of on the permeability of hardened concrete.
The effect of permeability on the concrete structure.
The approximate percent increase in the coefficient of permeability if the w/c ratio increases from 0.5 to 0.6.
The approximate percent increase in the coefficient of permeability if the w/c ratio increases from 0.5 to 0.7.
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What is the effect of water–cement ratio on the permeability of hardened concrete? How does permeability affect the durability of the concrete structure?Using Figure 7.33, what is the approximate percent increase in the coefficientof permeability if the water–cement ratio increases from 0.5 to 0.6? Using thesame figure, what is the approximate percent increase in the coefficient ofpermeability if the water–cement ratio increases from 0.5 to 0.7?
A) as follows
1- The reason for the decrease in concrete resistance when the temperature rises?
2- Reasons for preferring ready-mixed concrete over other types of concrete? 3- Why is it not preferred to mix concrete for a period of time more than required?
4- Why is bonding between cement and aggregate paste more important in highly resistant concrete?
5- Why is it important to get rid of the isolation phenomenon in soft concrete?
B) between by drawing the following situations?
1. The relationship between checking the compaction factor and checking precipitation
2- The relationship between compressive strength and life of concrete containing fly ash in days
For fine aggregate: bulk specific gravity=2.60, SSD Bulk Specific Gravity=2.63, apparent Specific gravity= 2.68, percent absorption=1.54%
For coarse aggregate= bulk specific gravity= 2.62, SSD specific gravity=2.63, apparent specific gravity= 2.65, percent absorption=1.70%
From the data above, what can you conclude about these bulk aggregate, ssd bulk specific gravity, apparent specific gravity, and percent absorption?
What is the effect of these value in concrete?
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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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.Similar questions
- As follows: 1- The reason for the decrease in concrete resistance when the temperature rises? 2- Reasons for preferring ready-mixed concrete over other types of concrete? 3- Why is it not preferred to mix concrete for a period of time more than required? 4- Why is adhesion between cement and aggregate paste more important in highly resistant concrete 5- Why is it important to get rid of the isolation phenomenon in soft concrete?arrow_forward6. Discuss the different types of volume change in concrete at early and long-term ages.arrow_forwardThe water–cement ratio is important because it influences all of the desirable qualities of concrete. a. Referring to Figure 6.10, which portion of water is used to calculate the water–cement ratio?b. What is a typical water–cement ratio for normal strength concrete?c.What is the water–cement ratio needed for hydration only when concrete is in the plastic state?d.Why is the extra water necessary?e.Briefly describe how super high strength concrete (fc′=15,000 psi) can be made.arrow_forward
- A concrete test cylinder is tested in compression after 7 days of moist curing. If the strength is 22.5 MPa, what do you predict for the projected 28-day strength knowing that the sample only gain 80% strength at 7 days?arrow_forwardA1-What is the bond strength between steel and concrete and how it can be calculated? 2-What is the segregation of fresh concrete? Give its reason and how to control it? V3- What are the advantages of concrete? 3- Discuss the effect of age and curing on the compressive strength of concrete. 5-What are the main purposes of using plasticizer admixtures? 6-What are the main techniques that should be used to reduce heat of hydration in massarrow_forwardDiscuss five different desirable characteristics of aggregate used in portland cement concrete.arrow_forward
- 1. What are the most common applications for structural steel?2. What is the purpose of reinforcing steel in concrete? Discuss the qualities of reinforcing steel in general.3. Discuss briefly four kinds of heat treatment used to improve the characteristics of steel. What are the benefits of each kind of treatment?arrow_forwardThree 100*200 mm cylindrical concrete specimens were tested for 28 days compressive strength and show 25.5 MPa, 28.6 MPa and 24.8 MPa compressive strength. a) What is the average compressive strength of this concrete? b) What is the approximate tensile strength of this concrete? c) What is the approximate modulus of elasticity of this concrete?arrow_forwardThe results of a laboratory experiment to evaluate the effects of a plasticizer are shown.a. Calculate the water/cement in each of the three cases. b. Choose an appropriate case that - by using water reducer, how can we increase the compressive strength of concrete without changing workability? (Refer to the appropriate case in the table) c. Choose an appropriate case that - by using a water reducer, how can we improve workability without changingthe compressive strength? (Refer to the appropriate case in the table)d. Choose an appropriate case that - by using water reducer, how can we reduce cost without changing workability or strength? (Refer to the appropriate case in the table)arrow_forward
- The moisture content of coarse aggregate is 0.60%. If the mass of the aggregate is 1,290 kg, adjust the mass of the aggregate. If the volume of sand is 0.30 cubic meter and its specific gravity is 1.50, what is the mass of the sand? If the mass of mixing water is 175 kg, and the required water-cement ratio is 0.65, how much cement powder is needed in the concrete mix? If the target slump of concrete is 160 mm, the maximum nominal size of the coarse aggregate is 37.5 mm, and the smallest nominal size is 9.5 mm, what is the estimated entrapped air in the ordinary concrete mix? The nominal maximum size of coarse aggregate is 25mm, the fineness modulus of coarse aggregates is 2.80, dry rodded mass of coarse aggregates is 1,100 kg and the fineness modulus of fine aggregates is 2.50. How much coarse aggregates is needed in the concrete mix? If the nominal maximum size of coarse aggregates is 25mm, what is the first estimate of air-entrained concrete?arrow_forwardQ4: A: What is self-consolidating concrete? How are its properties achieved? How are these properties measured? B: What are the three mineralogical or geological classifications of rocks, and how are they formed?arrow_forwardThe portland cement association recommends a minimum cement content of ______ for concrete placed under water • 360 kg/m^3 • 385 kg/m^3 • 335 kg/m^3 • 350 kg/m^3arrow_forward
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