In order to evaluate the suitability of nonpotable water available at the job site for mixing concrete, six standard mortar cubes were made using that water and six others using potable water. The cubes were tested for compressive strength after 7 days of curing and produced the loads to failure (in kN) shown in Table P6.21. a. Based on these results only, would you accept that water for mixing concrete according to ASTM C94? b. According to ASTM C94, are there other tests to be performed to evaluate the suitability of that water? Discuss briefly. TABLE P6.21 Cubes Made with Cubes Made with Potable Water Nonpotable Water 64.6 73.5 70.4 74.8 63.0 79.7 71.6 69.8 70.6 83.7 64.0 74.4

In order to evaluate the suitability of nonpotable water available at the job site for mixing concrete, six standard mortar cubes were made using that water and six others using potable water. The cubes were tested for compressive strength after 7 days of curing and produced the loads to failure (in kN) shown in Table P6.21. a. Based on these results only, would you accept that water for mixing concrete according to ASTM C94? b. According to ASTM C94, are there other tests to be performed to evaluate the suitability of that water? Discuss briefly. TABLE P6.21 Cubes Made with Cubes Made with Potable Water Nonpotable Water 64.6 73.5 70.4 74.8 63.0 79.7 71.6 69.8 70.6 83.7 64.0 74.4

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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Given the four concrete mixes as shown in the table below, one without water reducers and three (c1-c3) with water reducer. The most economic mix where the workability and compressive strength maintained as for the original mix (the mix without water reducers) is With water Reducer Without water Reducer C1 C2 C3 Cement, Kg/m3 850 765 850 850 Water, Kg/m3 465 419 370 465 Slump, mm 50 S1 50 S2 Compressive Strength (MPa) 38 fc1 fc2 fc3 Select one: O A. C3 О В. С2 О С.С1 O D. C1 and C2
Three 150 mm * 300 mm concrete cylinders with water to cement ratios of0.4, 0.6, and 0.8, respectively. After curing for 28 days, the specimens weresubjected to increments of compressive loads until failure. The load versusdeformation results were as shown in Table P7.26. Assuming that the gauge length is the whole specimen height, it is required todo the following:a. The compressive stresses and strains for each specimen at each loadincrement.b. Plot stresses versus strains for all specimens on one graph.c. The ultimate strength for each specimen.d. The modulus of elasticity as the secant modulus at 40% of the ultimatestress for each specimen.e. The strain at failure for each specimen.f. The toughness for each specimen.g. Comment on the effect of increasing the water–cement ratio on thefollowing:i. Ultimate strengthii. Modulus of elasticityiii. Ductilityiv. Toughness. Curves may be approximated with a series of straight lines.
Three 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.
Please give me both a and b answers a. If a concrete with 28 day compressive strength of 4500 psi is being poured, then it how much strength would you expect after 7 days(assuming good curing conditions)? Explain how you obtain the 7 day strength? b. Briefly explain the effect of water to cement ratio on concrete strength?
2. What is the standard size of PCC specimens to be tested for compressive strength? If a smaller size is used, which size is expected to provide higher compressive strengths? Why? Which size provides strengths close to that of an actual concrete structure? 3. What is the purpose of performing the flexure test on concrete? How are the results of this test related to the compressive strength test results? 4. What are the advantages of using a third-point loading flexure test over a center-point loading flexure test? Draw a shear force diagram and a bending moment diagram for each case to support your answer.
Two batches of concrete cylinders were made with and without a calcium chloride (CaCl2) accelerator admixture. Six cylinders were made of each batch and submerged in water for different times before testing for compressive strength and the results are shown in Table P6.34. It is required to do the following: a. Using an Excel sheet, plot the relationship between curing time and compressive strength of the two mixes on the same graph. Label all axes and curves. b. Comment on the effect of the accelerator on the compressive strength of PCC at early and late ages. TABLE P6.34 Cylinder no. 1 2 3 4 5 6 Water submergence (days) Compressive strength of plain concrete (MPa) Compressive strength of concrete with accelerator (MPa) 1 3 7 14 21 28 0.8 7.8 15.8 21.1 24.5 26.8 6.2 14.8 20.1 24.0 25.9 26.8
The following table represents a concrete mixture that has not been completely proportioned. The values given are the theoretical mixture proportions (oven dry basis). Material properties are also provided. Please answer the question at the end of the information given. Theoretical Mixture Proportions (oven dry basis) Water Cement Air Coarse Aggregate ASTM C 150 Type I Cement: Specific Gravity: 3.15 Coarse Aggregate: Well-graded 3/4 in. NMSA rounded gravel Oven-dry specific gravity: 2.63 Absorption: 1.10% Moisture content of stockpile: 3.10 % Oven-dry bulk density: 101.5 lb/ft³ Fine Aggregate: Natural Sand Oven-dry specific gravity: 2.60 Absorption: 3.20% Moisture content of fine stockpile: 3.50% Fineness Modulus: 2.80 265 lb/yd³ 675 lb/yd³ 6.00 % 1816 lb/yd³ What is the theoretical unit weight (in lbs/yd³) of fine aggregate in this concrete mixture (oven dry basis)? Round to the nearest whole number and do not include units when entering your answer.
1) What is the recommendations of Density, Absorption and Voids in Hardened Concrete lab test? 2) What is the errors that might happen on this lab test and how to prevent it? Recommendations for at least 4 industrial applications with details provided. do it academically and Do not copy, write it as a points