Materials for Civil and Construction Engineers (2nd Edition)
null Edition
ISBN: 9781292154411
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 7, Problem 7.38QP
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 0.15 m by 0.15 m and a span of 0.45 m. 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 32.8, 34.5, and 31.7 kN, while the loads at failure of beams with admixture were 39.4, 35.6, and 35.0 kN. Determine:
- a. The modulus of rupture of each beam in MPa.
- 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.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
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 0.15 m by 0.15 m and a span of 0.45 m. The third-point loadingflexure strength test was performed on each beam after 7 days of curing. The loads at failure of the beams without admixture were 32.8, 34.5, and 31.7 kN, while the loads at failure of beams with admixture were 39.4, 35.6, and 35.0 kN. Determine:a. The modulus of rupture of each beam in MPa.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.
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 sectionof 0.15 m by 0.15 m and a span of 0.45 m. The third-point loading flexurestrength test was performed on each beam after 7 days of curing. The loads atfailure of the beams without admixture were 32.8, 34.5, and 31.7 kN, whilethe loads at failure of beams with admixture were 39.4, 35.6, and 35.0 kN.Determine:a. The modulus of rupture of each beam in MPa.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 addingthe admixture.
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 100 mm * 100 mm and a span of 300 mm. A center-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 26.89, 22.56, and26.40 kN, while the loads at failure of beams with admixture were 32.47,32.49, and 31.06. Determine:a. The modulus of rupture of each beam in GPa.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 addingthe admixture.
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
Knowledge Booster
Learn more about
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
- 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.arrow_forwardchoose the correct answer Q1A- Which test gives more variable one of the modulus of rupture * 1-Center-point loading test 2-Two-point loading 3-Splitting tension test 4-Direct tension test B- Which process comes after batching in the manufacturing process of concrete? * 1-Transportation 2-Placing 3-Mixing 4-Compacting C- Excess vibration during compacting can lead to: * 1-Bleeding 2-Segregation 3-High strength 4-Air bubblesarrow_forwardThree batches of concrete were prepared using the same materials and ingredients, except that they have water–cement ratios of 0.50, 0.55, and 0.60,respectively. The following tests were performed on specimens made of thethree batches:■ Compressive strength test on 100 mm * 200 mm cylinders■ Center-point flexure test on 100 mm * 100 mm * 300 mm beams■ Split tension test on 150 mm * 300 mm cylindersThree replicates were tested for each test. Table P7.38 shows the average failure loads for the three replicates of each case.It is required to do the following:a. Complete Table P7.38b. Using an Excel sheet, plot the relationships between water–cement ratioand compressive strength, modulus of rupture, and tensile strength on thesame graph. Label all axes and curves.c. Comment on the effect of water–cement ratio on the compressive strength,modulus of rupture, and tensile strength.arrow_forward
- You are assigned to monitor the concrete strength gain at a construction site. The ultimate compressive strength of the concrete at its full maturity is 450 kg/m. The average concrete temperature at the construction site is 25 °C during the day and 15 °C during the night (assuming 12-hour day/night cycles). If you assume that the datum temperature (To) is - 10 °C, estimate the strength of concrete after 14 days. (4=35, B=51)Maturity Index, M = E(T - To).arrow_forwardThree concrete mixes with the same ingredients, except the amount of mixing water, and their slump values were obtained. Three 150 mm * 300 mm concrete cylinders were prepared for each mix. The cylinders were cured for 7 days and then tested for compressive strength. The test results are as shown. Assume that the aggregate was at the saturated surface-dry condition before adding mixing water.It is required to do the following:a. Determine the compressive strength of each cylinder after 7 days.b. Determine the average compressive strength of each mix after 7 days.c. Determine the w/c ratio for each mix.arrow_forwardCalculate the modulus of elasticity Ec of lightweight concrete that has a unit weight of 110 pcf and compare it to the modulus of elasticity Ec of a normal weight concrete. Both concretes have compressive strengths (f’c) of 4000 psi. Express the solutions in psi units. Please also explain why the values are different.arrow_forward
- Design the concrete mix according to the following conditions:Design EnvironmentBuilding frameRequired design strength = 27.6 MPaMinimum dimension = 150 mmMinimum space between rebar = 40 mmMinimum cover over rebar = 40 mmStatistical data indicate a standard deviation of compressive strength of2.1 MPa is expected (more than 30 samples).Only air entrainer is allowed.Available MaterialsAir entrainer: Manufacture specification 6.3 mL/1% air/100 kg cement.Coarse aggregate: 19 mm nominal maximum size, river gravel (rounded)Bulk oven-dry specific gravity = 2.55, absorption = 3.6,Oven-dry rodded density = 1761 kg/m3Moisture content = 2.5,Fine aggregate: Natural sandBulk oven-dry specific gravity = 2.659, absorption = 0.5,Moisture content = 2,Fineness modulus = 2.47arrow_forwardThe third-point loading flexure strength test was performed on a concrete beam having a cross section of 0.15 m by 0.15 m and a span of 0.45 m. If the load at failure was 35.7 kN, calculate the flexure strength of the concrete. This normal-weight concrete has an average compressive strength of 20 MPa. What is the estimated flexure strength (hints: use the ACl equation)?arrow_forwardA project specifies a concrete strength of at least 3000 psi. Materials engineers will design the mix for a strength higher than that. Calculate the required average compressive strength of the mix design if the standard deviation is s = 350 psi. Estimate the modulus of elasticity of the concrete at the required average compressive strength (the calculated strength, not the given strength).arrow_forward
- A concrete cylinder of diameter 150mm and length 300mm when subjected to an axial compressive load of 240KN resulted in an increase of diameter by 0.127mm and a decrease in length of 0.28mm.compute the values 1.poison ratio 2.modulus elasticityarrow_forwardThe design engineer specifies a concrete strength of 3700 psi. A plant where s = 300 psi for 41 test results. Which is the required average compressive strength to be used in your mix design? a. 3900 psi; b) 4000 psi; c)4 100 psi; d) 4200 psiarrow_forwardThree batches of concrete were prepared using the same materials and ingre-dients, except that they have water–cement ratios of 0.50, 0.55, and 0.60,respectively. The following tests were performed on specimens made of thethree batches:■ Compressive strength test on 4′′ * 8′′ cylinders■ Center-point flexure test on 4′′ * 4′′ * 12′′ beams■ Split tension test on 6′′ * 12′′ cylindersThree replicates were tested for each test. Table shows the average failure loads for the three replicates of each case.It is required to do the following:a. Complete Tableb. Using an Excel sheet, plot the relationships between water–cement ratio and compressive strength, modulus of rupture, and tensile strength on the same graph. Label all axes and curves.c. Comment on the effect of water–cement ratio on the compressive strength, modulus of rupture, and tensile strength.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Structural Analysis (10th Edition)Civil EngineeringISBN:9780134610672Author:Russell C. HibbelerPublisher:PEARSONPrinciples of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781337705028Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage Learning
- Fundamentals of Structural AnalysisCivil EngineeringISBN:9780073398006Author:Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel LanningPublisher:McGraw-Hill EducationTraffic and Highway EngineeringCivil EngineeringISBN:9781305156241Author:Garber, Nicholas J.Publisher:Cengage Learning
Structural Analysis (10th Edition)
Civil Engineering
ISBN:9780134610672
Author:Russell C. Hibbeler
Publisher:PEARSON
Principles of Foundation Engineering (MindTap Cou...
Civil Engineering
ISBN:9781337705028
Author:Braja M. Das, Nagaratnam Sivakugan
Publisher:Cengage Learning
Fundamentals of Structural Analysis
Civil Engineering
ISBN:9780073398006
Author:Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel Lanning
Publisher:McGraw-Hill Education
Traffic and Highway Engineering
Civil Engineering
ISBN:9781305156241
Author:Garber, Nicholas J.
Publisher:Cengage Learning
Concrete Slab Calculations 006; Author: Jerry Howard;https://www.youtube.com/watch?v=R19jILyBxio;License: Standard Youtube License