Calculations and Graphs For Concrete Mix Design

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This lab was about concrete mix designs. we did the lab test twice one was after 14 days and the second one was after 28 days. I will upload the results sheet and it will includes 5 teams results my team is ( B2 ). You will need to make 5 graphs based on all teams results, but the rest of the lab will be about my team. please do not use ( we did , I did ) in the lab report.

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1- results sheet.

2- lab manual guide for how to write the lab report.

3- how will the lab report will be graded sheet.

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IV. Lab #1Concrete Mix Design and Compression Tests A. Objectives: 1. To familiarize the student with the general characteristics of concrete and concrete materials and with laboratory methods of manufacture and test of concrete specimens 2. To determine the effect of varying design mixes and materials (water, cement, sand, and coarse aggregate) on the consistency of the fresh concrete and on the strength of the hardened material. B. References: ASTM C143-12 Standard Test Method for Slump of Hydraulic-Cement Concrete ASTM C39-05 Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens ACI Committee 211 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete, ACI 211.1-91, American Concrete Institute, 2002 ACI Committee 214 Evaluation of Strength Test Results of Concrete, ACI 214R-02, American Concrete Institute, 2002 C. Background: Portland cement concrete is a widely used building material for many reasons: it can be readily formed into many shapes; it is both durable and corrosion resistant; it provides fire protection and water tightness; and has a relatively high compressive strength. Although concrete exhibits low tensile strength, this disadvantage can be overcome by reinforcing it, normally with steel. The properties of concrete, in both the freshly mixed and the hardened state, are closely associated with the characteristics and relative proportions of its components. The solid portion of the hardened concrete is composed of the aggregate and a new product which is the result of a chemical combination of cement with water. The remaining portion of the space occupied by a given volume of concrete is composed of free water and air voids, with the air voids usually not occupying more than 1 or 2% of the volume , unless special chemicals (air entraining admixtures) are used to trap more air voids in the concrete. After a period of time, the amount of free water depends on the extent of chemical combination of water and cement, called hydration, and loss from evaporation. The cement-water paste is the active component in the concrete and the properties of the water-cement paste depend upon the characteristics of the cement, the relative proportions of cement and water, and the completeness of the chemical combination or hydration. The completeness of the hydration requires time, favorable temperatures, and the continued presence of moisture. The period during which the concrete is definitely subjected to these conditions is called curing. On construction work, curing may vary from 3 to 10 days; in the laboratory the common curing period is 28 days. Good curing is essential for the production of quality concrete. There are five types of Portland cement, as indicated below: Type I. For use in general concrete construction when the special properties specified for the other four types are not needed Type II For use in general concrete construction exposed to moderate sulfate action, or where moderate heat of hydration is required Type III For use when high early strength is required Type IV For use when a low heat of hydration is required Type V For use when high sulfate resistance is required All types are made of approximately 60% lime-bearing material and 40% of a clayey material, which are ground, mixed together, and then heated to fusion. The product is then ground fine and mixed with about 3% gypsum. A sack of cement contains 1 cubic foot of material and weighs 94 pounds. The sand and gravel (fine and coarse aggregate) used in a concrete mixture should be well proportioned or graded from fine to large particles. Sands generally vary in particle size from 1/4" down to those that pass a 100 mesh sieve (10,000 openings per square inch). Gravels vary upward from 1/4" to 1.5" and often to 2.5". If the sand and gravel are well graded, the void space will be minimized and less cement paste will be needed to produce concrete. Concrete mix proportions may be based on volume or weight of materials and are stated, for example, as 1-2.5-3.5 mix by volume, meaning that 1 part of cement, 2.5 parts of sand, and 3.5 parts of gravel, all by volume, should constitute the mix. The water-cement ratio (quantity of water divided by quantity of cement used) is the single most important factor influencing the strength of the final product. The only property of concrete which improves with a higher water-cement ratio is the workability, or the ease with which the concrete can be placed. Consistency relates to the state of fluidity of the mix an d ranges from the driest to the wettest mixtures. The most common test to determine consistency is the slump test (ASTM C143), which is performed by measuring the subsidence, or slump (in inches), of a pile of concrete 12" high, formed in a mold that has the shape of a cone. The tendency for water to rise to the surface of freshly placed concrete is known as bleeding, and results from the inability of the material to hold all the mixing water. Concrete subject to bleeding is not as strong or durable as concrete that does not bleed. The strength of concrete is taken as an important index of its quality. Strength tests are commonly made in compression and flexure and occasionally in tension. The compression test of a 6 by 12-inch (or 4 by 8inch) cylinder at age 28 days, after moist storage at a temperature of 70 of, is a standard ASTM test (ASTM C39). The compressive strength of concrete, made and tested under standard conditions, ordinarily varies from 2500 to 6000 psi, although much higher strengths can be obtained by using special additives. The tensile strength of concrete is roughly 10% of the compressive strength; and the flexural strength(strength in bending)of plain concrete, as measured by the modulus of rupture, is about 15 to 20% of the compressive strength. The principal factors affecting strength are: 1. Water-cement ratio -- the higher the water content, the lower the strength. 2. Age -- the strength of concrete generally increases with age, although practically all the strength has been achieved after 28 days. 3. Character of the cement -- the finer the cement, the higher the strength. 4. Curing condition -- the greater the period of moist storage, the higher the strength. Evaluation of strength data is required in many situations, such as: • Evaluation of mixture submittal; • Evaluation of level of control (typically called quality control); and • Evaluation to determine compliance with specifications (job - site acceptance testing) A strength test result is defined as the average strength of all specimens of the same age, fabricated from a sample taken from a single batch of concrete. A strength test cannot be based on only one cylinder; a minimum of two cylinders is required for each test. Concrete tests for strength are typically treated as if they fall into a distribution pattern similar to the normal frequency distribution curve. A sufficient number of tests are needed to indicate accurately the variation in the concrete produced and to permit appropriate statistical procedures for interpreting test results. To satisfy statistically based strength - performance requirements, the average strength of the concrete fcr′ should be in excess of the specified design compressive strength fc′. The required average strength fcr′ used in mixture proportioning depends on the expected variability of test results as measured by the coefficient of variation or standard deviation. The strength test record used to estimate the standard deviation or coefficient of variation should represent a group of at least 30 consecutive tests. If the number of test results available is less than 30, a more conservative approach is needed; and when the number of strength test results is less than 15, the calculated standard deviation is not sufficiently reliable to be of use. In those cases, the concrete is proportioned to produce much higher average strengths fcr′ than the specified design strength fc′. The strength of concrete in a structure and the strength of test cylinders cast from a sample of that concrete are not necessarily the same. The strength of the cylinders obtained from that sample of concrete and used for contractual (job - site) acceptance are to be cured and tested under tightly controlled conditions. The strengths of these cylinders are generally the primary evidence of the quality of concrete used in the structure.The engineer specifies the desi red strength, the testing frequency, and the permitted tolerance in compressive strength. It is impractical to specify an absolute minimum strength, because there is always the possibility of even lower strength test results simply due to random variation, even when control is good. D. Materials: Type I Portland cement, sand, gravel, and lubricant for molds E. Equipment: For mixing: scale for weighing, concrete mixer or mixing pan, shovels, trowel, slump cone, 12" scale, tamping rod, measuring beakers, mallet, wet towels, plastic, 3” by 6" or 4” by 8” cylinder molds (Note: 3 by 6” cylinders are not permissible when testing concrete strength by ASTM C39). For testing: rigid end caps, and concrete testing machine. F. Procedure: This experiment requires several laboratory periods. During the first period, concrete mixes will be designed and cylinders prepared for testing. Cylinders will be tested at four weeks (28 days) and either one week (7 days) or two weeks (14 days) after the first period. Specific instructions regarding the mix design will be given at the time of the experiment, using ACI 211.1 - 91 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete. Results will be compiled from all groups, with each group using a different water cement ratio for comparison and analysis. a. Concrete Mix Preparation 1Design one batch of non-air-entrained concrete, following the guidelines of the American Concrete Institute. Mix enough concrete to mold four test cylinders and to fill a slump cone. Mix the materials by first combining the sand and cement, then adding the gravel, and finally the water. Keep accurate records on the amount (by weight) of each of the materials used. 2- Once a mix has been prepared, its consistency should be measured with the slump cone apparatus, which is a truncated cone conforming to ASTM specifications. To make the slump test(ASTM C143), dampen the slump cone, scoop, tamping rod, and metal working surface. Holding the cone in position by standing on the foot pieces, fill the slump cone in three equal layers, rodding each layer 25 times with the tamping rod, making sure to cover the full area of the concrete with the tamping motion and that the strokes barely penetrate into the previous layer. For the final layer, pile the concrete above the top of the cone to account for settlement. If the level settles below the top of the cone, add additional concrete. Carefully strike off the surface using the tamping rod. Raise the slump cone by means of the handles, without any twisting or side motion. Place the cone next to the concrete, with the tamping rod over the cone. If one side of the concrete falls away or shears off, repeat the test. Measure the slump to the nearest 1/4" and classify the mix as wet (over 6"), normal (1-6"), or stiff (under 1"). The slump test is a good field test for consistency and may actually be used to determine the amount of mixing water. If the mix is outside the "normal slump" range, mix the concrete again and make adjustments to bring it into the normal range . If the slump is greater than that required, add more fine and/or coarse aggregates. If the slump is less than required, water and cement in the appropriate ratio should be added. Make sure that accurate records are kept of whatever materials are added so that the actual ratio of materials can be reported. 3. Observe the general characteristics of each mix, making note of its troweling workability. To determine troweling workability, work the concrete with a trowel. If it works smoothly and with little effort, the troweling workability may be called good. Rate as good, fair, or poor. 4. Fill the molds completely in three equal layers, tamping each layer 12 times, and each time tapping the sides of the mold 5 to 10 times with a mallet to remove air voids. Overfill the third layer to account for consolidation. Finish the top by striking off with the tamping rod and troweling it smooth. Cover the top immediately to prevent evaporation. 5. Properly identify samples and clean-up work area, equipment and tools. 6. Arrange for proper curing of your specimens (moisture and temperature). Strip the molds from the specimens after about a 24 - hour curing time. The samples then should be submerged in water or stored under wet burlap covered with plastic for 7 days. b. Compression Testing of Concrete Cylinders 1. Prior to compression testing, measure the diameter of the concrete cylinder using calipers. Measure the cylinder at mid - height at four different locations around the circumference of the cylinder. 2. Before testing the compression cylinders they must be capped on the ends to permit uniform bearing when the load is applied. A cap is a small plane surface of suitable material, such as gypsum plaster or hardened steel. Wipe clean the bearing faces of the hardened steel bearing caps and of the test specimen. Insert the test specimen into the bearing caps. 3. Place the test specimen with bearing caps in place on the table (platen)of the testing machine directly under the spherically seated (upper) bearing block. Wipe clean the bearing faces of the upper and lower bearing blocks. Seat the specimen in the testing machine and close the protective doors. 4. Apply the load continuously and without shock, at a constant rate within the range of 20 to 50 psi per second. During the application of the first half of the estimated maximum load, a higher rate of loading may be permitted. Do not make any adjustments in the controls of the testing machine while the specimen is yielding rapidly (immediately before failure). Increase the load until the specimen fails, and record the maximum load carried by the specimen during the test. Note the type of failure and the appearance of the concrete if the break appears to be abnormal. Standard failure modes are shown in Figure 1. MAKE SURE THE PLATEN DOES NOT RISE ABOVE THE MAXIMUM HEIGHT MARKED ON THE TESTING MACHINE. G. Calculations: 1. Record data from all lab groups in your lab section. Develop a data table to record the details and test results of each cylinder ,including : Group # Specimen # Mix date Test date Mix design proportions by weight Targeted compressive strength Cylinder size Slump Workability Ultimate load Ultimate compressive strength, and Type of fracture. Data tables will be shared among all groups by posting to shared files on the Campus Cruiser course web page. 2- The actual compressive strength is calculated as the failure load divided by the crosssectional area of the specimen. Report the strength to the nearest 10 psi. 3- Calculate the average compressive strength and range (difference between maximum and minimum strengths) for cylinders from the same mix(i.e. by lab groups in your section) and test date (i.e. same age at testing). Discuss the effect that age at testing has on compressive strength. 4- Using the average 28 day strengths for the different mix designs, plot a curve showing the compressive strength has a function of water/cement ratio, and discuss if your curve follows the expected trend. 5- Did your mix designs produce the strengths you were expecting at 28 days? What are some reasons why the actual average compressive strengths might not agree with the targeted compressive strengths from the mix designs? 6- The targeted compressive strength is the strength that is expected to be produced on average from a mix design. It is also known as the required average strength, fcr′ , but is NOT the same as the specified strength, fc′ ,engineers use in structural design calculations. The targeted strength must be larger than the specified structural design strength, fc′ ; how much larger depends on the quantity of test results available. The fewer the tests, the larger the amount by which fcr′ must be greater than fc′. For cases where there are not enough strength tests to establish a standard deviation (i.e. when there are less than 15 strength tests), the average compressive strength fcr′ must exceed the design strength fc′ by fcr′ ≥ fc′ + 1000 when fc′< 3000 psi fcr′ ≥ fc′ + 1200 when fc′ is between 3000 and 5000 psi fcr′ ≥ 1.10 fc′ + 700 when fc′ > 5000 psi Based on the above, make recommendations for reasonable values for design strength fc′ for which your concrete mix designs could be used. CE 206 Lab Report Grading Guide: Name: Lab Report: Date Submitted: Date Reviewed: OVERALL GRADING 1. 10% Performance and Preparation for the lab (including quizzes if appropriate) a. You are expected to be familiar with the objectives and lab procedures prior to the lab and you may be asked to write them prior to the start of the lab. Unannounced quizzes may be given prior to the lab to assess your preparation. 2. 90% Technical Content and Technical Writing (approximately equally weighted for lab reports, focus on technical content for Executive Summaries) a. Technical Content i. Tables ii. Figures iii. Calculations iv. Context of the lab (do you understand and can you convey the technical aspects of the lab) b. Technical Writing i. Correct format ii. Information is in the correct section iii. Sentence structure iv. Clarity, etc… In general, the following outline provides a summary of the information expected for each section of the report. CE 206 Lab Report Grading Guide: Name: Date Submitted: Lab Report: Date Reviewed: I. Abstract Does the abstract contain a clear statement of objectives? Good OK Not clear or complete Does the abstract contain a scope of work that describes the major tasks or activities completed in the lab to get data and results? Good OK Not clear or complete Does the abstract contain a summary of results or major findings? Good OK Not clear or complete II. Introduction Does the introduction contain a background stating the importance of the lab to engineering practice? Good OK Not clear or complete Does the introduction contain a clear statement of objectives? Good OK Not clear or complete Does the introduction contain a scope of work that describes the major tasks or activities completed in the lab to get data and results? Good OK Not clear or complete III. Background Does the background section contain all pertinent information needed for the reader to understand subsequent section of the report? Good OK Not clear or complete III. Methods and Procedures (M&P) Does the M & P contain a description of the types of samples/structures that were tested? Good OK Not clear or complete Does the M&P contain a description of the procedures used to obtain the required data? Good OK Not clear or complete Does the M&P contain a discussion of the methods of analysis (calculations, etc) that describes how the data are used to produce results? Good OK Not clear or complete IV. Results and Discussion Are the data presented in a logical/complete order to allow independent confirmation of results (sufficient information is provided to check the calculations) Good OK Not clear or complete Are tables or graphs of data and results properly presented? Good Are results properly presented and discussed to address objectives? Good OK Not clear or complete OK Not clear or complete Are there apparent or suspected errors in the results? NO Yes- minor Yes - major V. Conclusions Is there a summary of objectives and major results? Good OK Not clear or complete Are conclusions or recommendations presented? Good OK Not clear or complete VI. General Grammar and Mechanics Good OK Poor Formatting (Title Page, Appendices, References, etc) Good OK Poor or incomplete Overall Quality of Laboratory Work Good OK Poor Overall Quality/Appearance of Report Good OK Poor CE 206 Spring 2019 Section A1&2 Concrete Mix Designs – January 22&24, 2019 Required yield = 0.0232 yd3 For a 1 cubic yard mix design, all groups used 340 lbs water 1701 lbs (39.46lbs) coarse aggregate (maximum size = 3/4”) Group Target strength (psi) Water/cement ratio Cement (lbs) Sand (lbs) Slump (IN) A-1 4000 0.57 13.84/596 29.4/1267 7.5 A-2 4500 0.525 15.19/654 28.32/1219 8.25 A-3 5000 0.48 708 1174 4.5 B-1 6000 7.89/0.41 19.23/829 25.33/1092 2 B-2 4500 0.525 15.19/654 28.32/1219 7.5 14 day Peak load (lbs) Break geometry 56980 65535 68565 92600 73075 Local Sear wedge Local Sear wedge Local Sear wedge Cone Splitting Columnar / Splitting 14 day Peak load (lbs) Break geometry 14 day Peak load (lbs) Break geometry 28 day Peak load (lbs) Break geometry 28 day Peak load (lbs) Break geometry 28 day Peak load (lbs) Break geometry 49700 69295 63110 87950 75445 Local Sear wedge Local Sear wedge Local Sear wedge Shear Cone Cone Splitting 59695 68860 71720 94525 74585 Columnar / Splitting Full Shear Full Shear Cone Splitting Columnar / Splitting 65880 73635 60320 93750 72385 Cone Splitting Cone Splitting Local Sear wedge Cone Splitting Cone Splitting 60915 76400 84530 95650 83165 Local shear wedge Cone Splitting Conical Cone/Column splitting Cone Splitting 61195 68270 81470 94530 69960 Local shear wedge Local shear wedge Cone Splitting Cone Splitting Cone Splitting
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Running head: CONCRETE MIX DESIGN AND COMPARISON TESTS

Concrete Mix Design and Compression Tests
Course’s Name
Student’s Name
Professor’s Name
Institution
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Running head: CONCRETE MIX DESIGN AND COMPARISON TESTS

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Concrete Mix Design and Compression Tests
Abstract
The objectives of this laboratory experiment are to get familiar with the overall
characteristics of concrete and to identify the effect of different design mixtures and
materials including water, cement, and sand on the consistency of the fresh concrete as well
as on the strength of the hardened material. Through the experiment, the compressive
strength of five different samples of the concrete mix was calculated after 14 days and then
after 28 days, and those values were compared together in order to observe a huge
increment in the compressive strength of the concrete mix. Finally, the compressive
strength was compared to the corresponding target strength, and the difference between
those two types of strength was calculated from experimental results, and the difference
among the targeted strength and the structural design strength was identified.
Introduction
The lab is important to engineering practice because Portland cement concrete can
be widely applied because it tends to be formed into numerous shapes, it is hard to be
corroded, and it can keep the water tightness and the fire away and has a generally high
compressive strength. Even though concrete shows low rigidity, this weakness of concrete
can be resolved by having it fortified, typically with steel. The properties of cement, in both
the solidified state and the naturally mixed, are closely linked to the relative proportions
and the qualities of its ingredients, and the cement-water paste is the dynamic part in the
concrete as properties of the paste are dependent on the qualities of the cement, the relative
ratios of water and concrete, and the fulfilment of the chemical hydration and combination.
All of the above information was used to determine the ultimate load and thus the ultimate

Running head: CONCRETE MIX DESIGN AND COMPARISON TESTS

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compressive strength by diving the failure lord by the cross-sectional area, which is 6
inches x 12 inches for the first 3 samples (A-1, A-2 and A-3) and is 4 inches x 8 inches for
the last 2 samples (B-1 and B-2). From that the graphs were generated and the
computational strength was compared to the targeted strength obtained from the textbook
to draw conclusion about the design of the concrete mix.
Background
There are five distinct kinds of cement originated from Portland, and every kind of
cement is made of roughly 40% of a clayey material as well as 60% lime-bearing material
that is ground, mixed, and later on heated to the combination. The item is then ground fine
and blended with about 3% gypsum. A cement sack consists of 1 cubic foot of material and
weighs 94 pounds. The gravel and sand utilized in a mixture of concrete are wellproportioned or reviewed from fine to huge particles. Sands, in general, can fluctuate in the
size of the particle from 1/4" down to these which pass a 100 mesh sieve including 10,000
openings for every square inch. On the other hand, gravels differ upward from 1/4" to 1.5"
and regularly to 2.5". In the case that the gravel and sand are well reviewed, the void space
can be limited and less cement paste can be expected to create concrete. Therefore, the
proportions of concrete mix might be founded on volume or weight of materials and are
provided.
Methods and Procedures
The materials used in this lab experiment include Type I Portland cement, sand,
gravel, and lubricant for ...


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