1-fresh-and-hardened-concrete-test

y UTM UNIVERSITI TEKNOLOGI MALAYSIE RESEARCH UNIVERSITY CIVIL ENGINEERING LABORATORY CONCRETE LABORATORY [ STUDENT'S NAME/ i B == MATRIX NO: 2 ! 3 4 5 6. | 2 8 [ TOTAL MEMBERS: [ LECTURER: ] LABORATORY REPORT | 1 TITLE: 2 | TOTAL PAGES: DUE DATE: DATE OF SUBMISSION: DECLARATION 1/We declare that this laboratory report is mylour own work and does not involve plagiarism o unauthorized | collusion. Signaurels). Date ‘Assessment (please see overleaf for assessmen rubrics) Scores

C1 FRESH AND HARDENED CONCRETE TEST INTRODUCTION Conarete % testad during its fresheand hardened State mafhly to ensure that concrete mix satisfies the specification of works. In its fresh state, concrete is tested for its consistency so as to achieve the desired workability. Workability is an important property in concrete since a workable mix will produce concrete, which can be well compacted, transported and placed without segregation. A well-compacted concrete will produce a good strength concrete. Tests to be conducted on fresh concrete to measure its workability consists of: 1. Slump Test 2. Compacting Factor Test 3. Vebe Test Hardened concrete tests to destruction consists of: 1. Compression Test 2 Indirect Tension Test Methods 3. Flexural strength of concrete OBJECTIVE The objectives of the tests are to determine the properties of concrete as follows: 1. Workability of fresh concrete 2. Strength of hardened concrete

Example: Standard mix STS Slump:75mm Nominal Maximun size of aggregate: 20mm Constituent Table C1-2 (adopted from | Tests requirements ] Table 5: BS 5528 (1m* ¢ om) | concrete)] Cement 340 kg 340kg =1 kg Fine aggregate | 0351630 kg = 640 kg 640kg ~ ) Course aggregate | (1830 — 640) kg =1190kg | 1190kgx = &g Waler (W/c=05) |@5x340kg=170kg | #ekg» = Mix cement, fine and course aggregate in a mixer for 1 minute Add in water and mix approximately for another Tminute When the mix is ready. proceed with the workabilty tests Slump test 1. Place the cone on a smooth, flat and clean surface. 2. Fill the mould with 3 layers of concrete approximately of the same thickness each 3. Compaict each layer of concrete by tamping it 25 times with the standard steel rod Level the top surface of the concrete with a trowel. Lift the cone slowly vertically to aliow concrete to subside. Measure the difference in level between the height of the mould and that of the highest point of the subsided concrete. This difference in height in mm is taken as slump of concrete C1-3

Compacting Factor Test 1. Assemble the apparatus vertically, placing the bigger hopper uppermost, the smaller hopper in the middle and the cylinder at the bottom. 2. Clean thoroughly allinside surfaces of hoppers to reduce friction. 3. Each hopper has hinged door (trap-door) at the bottom. Make sure that this door is closed before commencing the test. Fill up the upper hopper with concrete to the brim. Release the door to let the concrete falls into the lower hopper Release the door of the second hopper to let the concrete fails into the cylinder. 7. Cut off excess concrete from the top of the cylinder by sliding it across with two floats. 8. Determine the net weight of the concrete. This weight is known as "weight of partially compacted concrete” 9. Empty the cylinder and refil it with the concrete from the same sample in three layers. Tamp each layer 25 times with standard steel rod. 10. Level off the top surface of the cylinder and weigh it to the nearest 10gm. This weight is known as *weight of fully compacted concrete’. 11. Calculate the compacting factor of concrete. The Compacting factor = weight of partially compacted concrete weight of fully compacted concrete

PROCEDURES Compression Test 9. Prepare three moulds of size 150mmx 150mmix150mm Thinly coat the interior surfaces of the assembled mould with mould ol to prevent adhesion of concrete. Fill each mould with three layers of concrete, tamp each layer 35 times with a 25mm square steel rod. Finish the top surface with a trowel and record the date of manufacturing on the surface of the concrete Store the cube undisturbed for 24 hrs at a temperature of 18 to 22°C and a relative humidity of not less than 80%. To ensure this condition cover the concrete with wet gunny sacks After 24 hours strip the mould and cure the cubes further by immersing them in water at temperature 19 o 21°C until the testing date. Test the cubes at the age of 7 days. Position the cube in the compressive machine with the cast faces in contact with the platens. Apply the load at the rate of 15 MN/m?/min 10. Record the maximum load to the nearest 0.5 Nimm?. Indirect Tension Test @ N o o> Prepare two moulds of cylinder measuring 150mm diameter by 300mm long Coat the inside surfaces of the mould with mould ol Fill each mould with three layers of concrete, tamp each layer 36 times with a 16mm § steel rod. Record the date on the surface of the concrete. Cure the cylinder. Method of curing is similar as for the cubes. Test the cylinder at the age of 7days. Place the cylinder with its axis horizontal between the platens of the testing machine.

8. Place narrow strips of plywood at the top and bottom between the platens and the cylinder 9. Apply the load at the rate of 1.6 MN/m?/min Flexural Strength of Concrete Prepare a mould of beam measuring 100x100»500mm long 2. Coat the inside surface of the mould with mould il 3. Fill the mould with 3 layers of concrete, tamp each layer 35 times with a 25mm square steel rod 4. Cure the beam The method of curing is similar as for the cubes Test the beam at the age of 7 days. 6. The beam is positioned for testing with a span of 400mm i e 50mm from each end 7. Impose the beam with a two point loading system 8. Apply the load at the rate of 1.6 MN/m?/min 9. Measure the position of the crack from the support 10. Calculate the modulus of rupture using the formuilae below. rL Modulus of rupture = A " A or

Table C1-1. Standard mixes and refated strengths ( Adopted from Table 3 BS 5528) [Standard mix - {Characteristic compressive strength at 28 (days assumed for structural design INfmm® ( = MPa) STI 7.5 ST2 10.0 [ST3 15.0 IST4 Po.o TS 25.0 ct9

Table C1-2. Mix proportion for standard mixes ( Adopted from Table 5 BS 5528) [Standard mix |Consituent [Nominal maximum size of ageregate o 140 mm Omm tump, fstump. btump Ftump [75 mm 125 mm S mm osom | (Cement (kg) 180 00 pro 30 STt [Total ageregate (kg) 1010 1950 1940 1850 (Cement (ke) pio P30 hao 6o sT2 [Total aggregate (ke) _|1950 1920 1920 1860 ement (ke) P40 keo ko b0 T3 otal ageregate (k) f1950 1900 1500 1820 (Cement (ie) bso 00 00 530 ST4_ [Total agercgate (ke) _ [1920 |1860 1568 1500 |cement (k) 520 B0 340 570 s [Total aggregate (k) 1820 1560 1830 o sT1 ine aguresate T2 ltpercentage by mass of [30 10 45 101045 55 10 50 T lotal aggregate) i [Fine agaresate Ity percentage by mass of 575 total aggregate) (Grading limits ¢ 0 t0 40 bstods (Grading limitsM 51030 150 10 40 [Gradimg lirnits F 25 1030 1035 1) When ST1 is required with a very low slump the proportions shall be taken from the 75 mm slump column. (OTE 1. The cement contents toether with the total masses of saturated surface dry aguregates and added water will produce approximately one cubic metre of concrete. The values given are based on typical values of the relative lensites of cement aggregates. For some arcutes having higher or lower refative densilies. adjusiments may be Irequired to the quantity of ageregates produce this volume of concrete having the required workabil leement content y and (OTE 2. The value given for agareuate cotent may be adjusted to allow also for the charscterstics of the ggregates as described in 4.3.2 of BS5320: Part 3:1990. (OTE 3. _The aggregates for mixes ST1, ST2 and ST may be batched by volume. C1-10

Cube test Load at failure Compressive strength of cube - Surface Arca Example:- Compressive strength of cube = Indirect Tensile Strength Indirect Tensile Strength DL Where, P = Cylinder Splitting load (kN) D = Diameter (mm) L = Height of cylinder (mm) Example Indirect Tensile Strength Flexural Strength of Beam Modulus of Rupture f, = :TI’ it a>533 6= Loy aesay e where, P = Maximum applied load (kN) L = Supported Span (mm) b = Widthof sample (mm) d = Depthof sample at crack (mm) Example Modulus of rupture, fo= RESULT Slump of Concrete = Compaction factor = V-B time = Mean Compressive Strength of Cube = c1-3

Indirect Tensile Strength = Flexural Strength S QUESTION AND ANSWER 1) Compare the results of the slump and vebe time measurements with the values adopted in the design process. Give your comments on the results 2) Compare the results of the strength tests with the target mean strength. Discuss on the results. Cl-4