Materials for Civil and Construction Engineers (4th Edition)
4th Edition
ISBN: 9780134320533
Author: Michael S. Mamlouk, John P. Zaniewski
Publisher: PEARSON
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Textbook Question
Chapter 1, Problem 1.46QP
A contractor claims that the mean compressive strength for a concrete mix is 5,000 psi and that it has a standard deviation of 400 psi. If you break 20 cylinders and obtain a mean compressive strength of 4,800 psi, would you believe the contractor’s claim? Why? (Hint: Use statistical t-test.)
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1.46: A contractor claims that the mean compressive strength for a concrete mix is 5000 psi (μ) and that it has a standard deviation of 400 psi (σ). If you break 20 cylinders (N) and obtain a mean compressive strength of 4,800 psi (m), would you believe the contractor’s claim? Why? (Hint; Use statistical t-test.) Next, what is the maximum number of breaks (N) that could be performed that WOULD make you believe the contractor’s claim? Assume that the results wouldn’t change, i.e. σ = 400 psi and m = 4,800 psi. Recall that the equation to find the lower bound of a one sided distribution is LB = μ - (tσ)* σ/(N^0.5) Because the sample size is relatively small, use the ‘student t test’ to represent the normal distribution. You should have at least 95% confidence in the results. That means that α = 0.05. Keep in mind that this is a one tailed distribution, since we only care about the lower bound (i.e. meaning that we are only concerned about concrete that doesn’t meet our minimum strength…
A contractor claims that the mean compressive strength for a concrete mix is 4,830 psi and that it has a standard deviation of 430 psi obtained from testing 22 specimens. If you break 20 cylinders and obtain a mean compressive strength of 4,450 psi and a standard deviation of 480 psi, would you believe the contractor’s claim? Why? (With a 95% confidence interval)
Given the image below.
What is the maximum diameter of aggregate considering the
narrowest dimension of the beam in cm if the value of c is 40cm and
the value of e is 69cm?
slab
Oslab=10mm
Obeam=25™m
beam
b
e
Chapter 1 Solutions
Materials for Civil and Construction Engineers (4th Edition)
Ch. 1 - State three examples of a static load application...Ch. 1 - A material has the stressstrain behavior shown in...Ch. 1 - A tensile load of 50.000 lb is applied to a metal...Ch. 1 - A tensile load of 190 kN is applied to a round...Ch. 1 - A cylinder with a 6.0 in. diameter and 12.0 in....Ch. 1 - A metal rod with 0.5 inch diameter is subjected to...Ch. 1 - A rectangular block of aluminum 30 mm 60 mm 90...Ch. 1 - A plastic cube with a 4 in. 4 in. 4 in. is...Ch. 1 - A material has a stressstrain relationship that...Ch. 1 - On a graph, show the stressstrain relationship...
Ch. 1 - The rectangular block shown in Figure P1.11 is...Ch. 1 - The rectangular metal block shown in Figure P1.11...Ch. 1 - A cylindrical rod with a length of 380 mm and a...Ch. 1 - A cylindrical rod with a radius of 0.3 in. and a...Ch. 1 - A cylindrical rod with a diameter of 15.24 mm and...Ch. 1 - The stressstrain relationship shown in Figure...Ch. 1 - A tension test performed on a metal specimen to...Ch. 1 - An alloy has a yield strength of 41 ksi, a tensile...Ch. 1 - Prob. 1.21QPCh. 1 - Figure P1.22 shows (i) elasticperfectly plastic...Ch. 1 - An elastoplastic material with strain hardening...Ch. 1 - A brace alloy rod having a cross sectional area of...Ch. 1 - A brass alloy rod having a cross sectional area of...Ch. 1 - A copper rod with a diameter of 19 mm, modulus of...Ch. 1 - A copper rod with a diameter of 0.5 in., modulus...Ch. 1 - Define the following material behavior and provide...Ch. 1 - An asphalt concrete cylindrical specimen with a...Ch. 1 - What are the differences between modulus of...Ch. 1 - Prob. 1.33QPCh. 1 - A metal rod having a diameter of 10 mm is...Ch. 1 - What is the factor of safety? On what basis is its...Ch. 1 - Prob. 1.36QPCh. 1 - Prob. 1.37QPCh. 1 - A steel rod, which is free to move, has a length...Ch. 1 - In Problem 1.38, if the rod is snugly fitted...Ch. 1 - A 4-m-long steel plate with a rectangular cross...Ch. 1 - Estimate the tensile strength required to prevent...Ch. 1 - Prob. 1.42QPCh. 1 - Briefly discuss the variability of construction...Ch. 1 - In order to evaluate the properties of a material,...Ch. 1 - A contractor claims that the mean compressive...Ch. 1 - A contractor claims that the mean compressive...Ch. 1 - Prob. 1.47QPCh. 1 - Prob. 1.48QPCh. 1 - Prob. 1.49QPCh. 1 - Briefly discuss the concept behind each of the...Ch. 1 - Referring to the dial gauge shown in Figure P1.51,...Ch. 1 - Repeat Problem 1.51 using the dial gauge shown in...Ch. 1 - Measurements should be reported to the nearest...Ch. 1 - During calibration of an LVDT, the data shown in...Ch. 1 - During calibration of an LVDT, the data shown in...
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- A concrete test cylinder having length L=12 in and diameter d=6 in is subjected to axial compressive forces P in a testing machine. If the maximum shear stress in the concrete is not to exceed 2,000 psi, what is the safe value for the axial load p?A. 452,389 lb. B. 113,100 lb. C. 904,778 lb. D. 56,550 lb. The answer for this is letter B 113,100 lb but I dont know its solution. Please give me complete solution in order to get the 113,100 lb.arrow_forwardWhen describing the behavior of concrete under load, the popular belief is that concrete will crush when the unit strain reaches 0.003. if a 12-in tall concrete test cylinder is tested to the failure point in a testing machine what will be its height when it fails?arrow_forward150mm cylindrical concrete specimen was tested for tensile strength. When the applied load is 180,000N, the sample failed with a tensile strength of 2.55MPa. What is the length of the specimen in mm? Round off your answer to the nearest whole number.arrow_forward
- complete the table and answer questarrow_forwardIn a ready-mix plant, cylindrical samples are prepared and tested periodically to detect any mix problem and to ensure that the compressive strength is higher than the lower specification limit. The minimum target value was set at 5,000 psi. The compressive strength data shown in Table were collected. a. Calculate the mean, standard deviation, and the coefficient of variation of the data. b. Using a spreadsheet program, create a control chart for these data showing the lower specification limit. Is the plant production meeting the specification requirement? If not, comment on possible reasons. Comment on the data scatter.arrow_forwardWhat is the maximum diameter of aggregate in cm?arrow_forward
- Q3) The result of sieve analysis of a sample of aggregate given in the Table below. According to ASTM C 33, the sample is acceptable or not? BS Total mass of sample 4 80 g Sieve size 10 mm 5 mm 2.36 mm 1.18 mm 600 μm 300 μm 150 μm €150μm ASTM in 4 8 16 30 50 100 <-100 Mass retained O 80 40 80 110 68 61arrow_forwardA cylindrical concrete specimen was tested for compressive strength. The stress at failure was 22.64 MPa when the applied force was 400,000N. What is the diameter of the specimen in mm? Round off your answer to the nearest whole number.arrow_forwardThe question is in the picture. Help please, thanksarrow_forward
- 25. M20 concrete is a grade of concrete which has a compressive strength equal to 20 MPa. I want to test if concrete with a raction of cement partially replaced with fly ash would be competftive with M20 concrete. What test should I perform given limited time and resources? O A. One sample t-test O B. One sample z-test O C. Two sample t-test D. Two sample z-testarrow_forwardThe data gathered from an experiment to determine the specific gravity of aggregates were summarized in the table below. Weight of FA sample (grams) 171.06 Weight of SSD sample (grams) 175.38 Weight of pycnometer with water (grams) 441.38 Weight of pycnometer with SSD sample and water 541.03 (grams) Weight of oven-dry sample (grams) 166.85 Calculate the bulk-specific gravity (dry). Round your answers to three decimal places.arrow_forwardSECTION A Answer ALL Questions Physical and mechanical properties of civil engineering materials, their behaviour and characteristics in design and construction works. Answer below questions using your own words and understanding. (a) (i) Design a concrete mix for the following given data: A mean 28-day compressive strength (measured on standard cubes) of 45 MPa Slump = 40 mm, Uncrushed aggregate with maximum size of 20 mm Specific gravity of aggregate = 2.64 Fine aggregate passes through the 600 µm sieve = 48% No air entrainment required, ordinary Portland cement to be used. [Use supplied charts and table to get required values]arrow_forward
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