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A 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).
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- If you knew that the cubic compressive strength of a certain type of concrete is 35 MPa, then calculate the resulting load during the examination, the maximum force applied by the test device)? 1- Fission tensile test 2- Fault modulus test 3- Compressive test for cylinderarrow_forward2. In a ready-mix concrete 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 following compressive strength data were collected. Sample No. 1 2 3 4 5 6 7 8 9 10 Compressive strength (psi) 5595 5139 6359 5192 5188 5241 5964 5875 6155 5115 Sample No. 11 12 13 14 15 16 17 18 19 20 Compressive strength (psi) 6695 5449 5278 6697 5195 6021 5320 5657 6595 5235 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 target value and the lower specification limit. Is the plant production meeting the specification requirement? If not, comment on possible reasons. Comment on the data scatter.arrow_forwardA. What are the primary and secondary parameters upon which durability of concrete depends on? Discuss in detail one PRIMARY PARAMETER to which concrete is exposed in the image shown: *arrow_forward
- A concrete mix includes the following ingredients per cubic meter: Cement%3D400 kg Water=184 kg No admixture Table below shows possible alternatives mix ingredients. Indicate in the appropriate boxes in the table what will happen in each case for the workability and the ultimate compressive strength as increase, decrease or approximately the same. What will happen? Cement Water Admixture (kg) (kg) Ultimate compressive Workability strength 400 225 None 449 184 None Water 400 184 Reducer Water 400 128 Reducer 400 184 Super Plasticizer 400 184 Air Entrainer 400 184 Accelerator DFocusarrow_forwardIn compressive strength testing of concrete, which type of concrete will give a more accurate result. 100mm by 100mm cubed concrete or 100mm cylinder concrete. Why?arrow_forwardConcrete is required for a column that will be Severe exposed to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 30 mm. The Required Average Compressive Strength of concrete at 28 days is 35 MPa with a slump of 80 to 100 mm. The properties of materials are as follows: ❖ Cement used is type I Portland cement with a specific gravity of 3.15. ◆ The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.7, absorption capacity of 0.55%, and moisture content (SSD) of 0.25%. The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.4%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.70. The aggregates conform to the ASTM C33-84 requirements for grading.arrow_forward
- 6. Discuss the different types of volume change in concrete at early and long-term ages.arrow_forward4b. Deformation occurs on freshly lay concrete when it finally set or harden.discuss the various causes for dimensional changes in the hardened concrete.arrow_forwardQ3: B: Design the concrete mix according to the following conditions: Design Environment Building frame Required design strength = 27.6 MPa Minimum dimension = 150 mm Minimum space between rebar = 40 mm Minimum cover over rebar = 40 mm Statistical data indicate a standard deviation of compressive strength of 2.1 MPa is expected (more than 30 samples). Only air entrainer is allowed. Available Materials Air 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/m3 %3D Moisture content = 2.5, Fine aggregate: Natural sand Bulk oven-dry specific gravity 2.659, absorption=0.5, Moisture content = 2, Fineness modulus = 2.47arrow_forward
- Which one of the following sentences is not correct? a.For many years, tensile strength has been measured in terms of the compressive strength. b.The modulus of rupture where the normal-weight concrete has an fc of 4000 psi is 474 psi. c.For lightweight concretes tensile strength depends largely on the porous aggregate. d.For normal weight concrete, the tensile strength depends primarily on the strength of bond between hardened cement paste and aggregate.arrow_forwardConcrete is required for a column that will be Severe Exposure to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 40 mm. The specified compressive strength of concrete at 28 days is 40 MPa with a slump of 25 to 50 mm. The properties of materials are as follows: (a) Cement used is type I Portland cement with a specific gravity of 3.10. (b) The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.68, absorption capacity of 0.65%, and moisture content (SSD) of 0.27%. (c) The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.5%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.7,The aggregates conform to the ASTM C33-84 requirements for grading.arrow_forwardChapter 13 Question: What is the elasticity of concrete for a normal weight mix (unit weight equal to 150 pcf) with a compressive strength of 5,000 psi? O 3.644 ksi O 4.074 ksi 4,287 ksi O 3.976 ksi O 3,834 ksiarrow_forward
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