Measuring and modifying hardness of metals - 1925 Words

Measuring and modifying hardness of metals (Lab Report Sample) Content: Aggregates Name Lecturer Date Abstract Aggregates are important material in the construction industry and can be defined as a granular material that is made of sand, crushed stone or gravels. The performance of material which is critical in the construction industry is dependent on the aggregate distribution. The sieve analysis and the void content and density analysis, are some of the methods used in distribution and quality of aggregate analysis. The report base it analysis on an experimental set up in which both void content and density and sieve test analysis is carried out using crashed granite and crushed rock respectively. The sieve analysis is done through passing of the sample aggregate through a set of sieves as shown in table one below. The retained aggregates are weighed and data collected used to fill the table 1 from which a graph of distribution is drawn. A graph of sieve mess size in x-axis (mm), cumulative % passing in the y-axis and cumulative percentage retained in the z-axis was drawn to reflect the aggregate distribution. The percentage difference between the initial sample aggregate and the cumulative sum of the retained aggregate which is 0.11% show that the experiment was successful and the analysis is based on accurate data. Table of Contents TOC \o "1-3" \h \z \u Introduction PAGEREF _Toc446083380 \h 3Aim and Objectives PAGEREF _Toc446083381 \h 4Apparatus PAGEREF _Toc446083382 \h 4Procedure PAGEREF _Toc446083383 \h 4Experimental Theory PAGEREF _Toc446083384 \h 5Experimental Results and Analysis PAGEREF _Toc446083385 \h 6SIEVE ANALYSIS PAGEREF _Toc446083386 \h 6VOID CONTENT AND DENSITY PAGEREF _Toc446083387 \h 8Discussion PAGEREF _Toc446083388 \h 9Conclusion PAGEREF _Toc446083389 \h 11References PAGEREF _Toc446083390 \h 12Appendices PAGEREF _Toc446083391 \h 12 Introduction Aggregates are can simply be defines as a granular materials that can either be natural, recycled or manufactured and are mostly used as construction material. Natural aggregates are extracted from large quarry rocks and reduced to the desired sizes through physical crushing. Aggregates can either be from sand, crushed stone and gravels. In construction industry during the preparation of both asphalt concrete and Portland cement concrete, aggregates are mixed together with water, Portland cement and sand. According to (Rogers, 1988) outline natural aggregates as the most abundant natural resource and it compost of crushed stone, sand and gravels. Aggregates are very important constructions, agriculture and industrial metallurgical processes. The quality of the mixture (concrete) depends on the quality of the input which collectively determines workability and pumpability. Factors such as the size of the aggregates, aggregate void content and the specific gravity of the aggregates affect the choice of aggregate to be used. However, sieve test is very important in determining the gradation or aggregate particle presence within a given mixture. Aim and Objectives Aim * To demonstrate the how laboratory test can be used to assess the physical properties of aggregate intended to be used in concrete. Objectives * To understand the grading specification of the aggregates * To determine sources of flaws in the sieving analysis experiment. * To understand the importance of the overload check during sieving experiment. * To demonstrate how variation of density is affected by the type of aggregate used. Apparatus * Balance/scale * Sieves * Mechanical sieve shaker * Suitable dry Equipment * Containers and Utensils * Optional mechanical washing devices Procedure (Sieve analysis process) * Take a dried oven sample of soil of the desired weight * Conglomerate the soil particle if they are lumped * Determine the weight of the soil sample accurately * Prepare the stuck of sieves with the larger being at the top and smaller size at the bottom. * Ensure the sieves are clean/ remove any stuck particles * Weigh all sieves and the pan separately * Pour the aggregates into the sieves from Top and place the cover, put the stack in the sieve shaker, shake the aggregate for about 10min. * Stop the sieve shaker and measure the sample of each sieve plus the retained soil. Experimental Theory Aggregates normally takes about 70% by volume of the concrete. Aggregates are classified as either manmade or natural and granular materials such as sand, gravel, crushed stone and blast furnace slag are few examples of aggregates. Aggregate analysis is important in concrete analysis because properties such as workability, durability, strength, thermal properties and the concrete density all depend on the quality of the aggregates used. Aggregates according to (Nmai, Suchorsk McDowel, 2013) can also be classified into wet, saturated surface dry, air-dry and oven dry depending on the moisture content. The figure below shows the classes of aggregates. Fig 1: Moisture condition of the aggregates (Nmai, Suchorsk McDowel, 2013) Sieve analysis is a test carried out to determine the grain size distribution within a given aggregate range. The test is named sieve analysis dust to the number of sieves arranged from large to small sieve size. The figure below shows an example of sieves. Fig 2: Sieve arrangement during sieving process The space between the aggregate that is left unoccupied is normally referred to as void. The percentage of the void in an aggregate is determined using the equation shown below Experimental Results and Analysis SIEVE ANALYSIS Description of the sample Crushed rock Mass of empty riffle box container, M=151g Mass of riffle box container + oven dry sample, M=2037g Mass of the oven dry sample, M= M- M=2037-151=1886 g Sieve set: B/E Sieve frame diameter, D: 300 mm Sieve area, A= (à Ã¢â€š ¬D/4): 70685.83 mm Overloading limit, M= (A/d)/200 Sieve mesh size, dn(mm) serial number of sieve overload limit for sieve Moverload(g) Mass of empty sieve(g) mass of sieve+retained sample(g) Mass of retained sample Mn(g) overload check:MoverloadMn %of M4 retained on sieve Rn Cumulative % retained,ÃŽÂ £Rn %finer= 100-ÃŽÂ £Rn BS/EN Limits for grade (%) pass or fail 14 5791991 1322.41 1103 1103 0 yes 0 0 100       10 5794662 1117.64 1067 1341 274 yes 14.528 14.528 85.472       8 5784231 999.64 1122 1698 576 yes 30.54 45.068 54.932       6.3 5771998 887.1 1157 1750 593 yes 31.442 76.51 23.49       4 5774862 706.85 1217 1576 359 yes 19.034 95.544 4.456       2.8 12030593 591.4 1193 1225 32 yes 1.696 97.24 2.76       2 12030592 499.82 1096 1104 8 yes 0.424 97.664 2.336       1 12031011 353.429 1204 1207 3 yes 0.159 97.823 2.177       pan N/A    750 793 43 yes 2.279 100 0                   ÃŽÂ £Mn 1888 M4                Table 1: Tabulated experimental values Mass lost or gained during sieving= (M-M/M) x 100 =à ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦Ãƒ ¢Ã¢â€š ¬Ã‚ ¦% (OK if 0.5%; check arithmetic if 0.5%, and repeat test if error not resolved) Calculations %of M4 retained on sieve Rn = (Retained mass/initial oven dry mass)x 100 Case 1= (0/1886) x100=0 Case 2= (274/1886) x100=14.528 Case 3= (576/1886) x100=30.54 Case 4= (593/1886) x100=31.442 Case 5= (359/1886) x100=19.034 Case 6= (32/1886) x100=1.696 Case 7= (8/1886) x100=0.424 Case 8= (3/1886) x100=0.159 Case 9= (43/1886) x100=2.279 Cumulative % retained, ÃŽÂ £Rn Case1= (case o+ case 1) = (0+0)=0 Case1= (case 1+ case 2) = (0+14.528)=14.528 Case1= (case 2+ case 3) = (14.528+30.54) =45.068 Case1= (case 3+ case4) = (45.068+31.442) =76.51 Case1= (case 4+ case 5) = (76.51+19.034) =95.544 Case1= (case 5+ case 6) = (95.544+1.696) =97.24 Case1= (case 6+ case 7) = (97.24+0.424) =97.664 Case1= (case 7+ case 8) = (97.664+0) =97.883 Case1= (case 9+ case 10) = (97.883+2.279) =100 Overloading limit, M= (Ad)/200 Case 1= (70685.83x 14)/200= 1322.41 Case 2= (70685.83x 10)/200 =1117.64 Case 3= (70685.83x 8)/200=999.64 Case 4= (70685.83x 6.3)/200= 887.1 Case 6= (70685.83x 4)/200= 706.85 Case 7= (70685.83x 2.8)/200=591.4 Case 8= (70685.83x 2)/200=499.82 Case 9= (70685.83x 1)/200= 353.429 Mass lost or gained during sieving= (M-M/M) x 100 = (1886-1888/1886) x100= 0.11% VOID CONTENT AND DENSITY Description of sample: Large core aggregates/Crushed granite Volume of empty glass container, V= 3.5 litres Voids content of sample, V: 47% Volume of void in the sample, V= (V/100) x V: (47/100) x 3.5= 1.645 litres Aggregates content of sample, A=100- V=53 % Volume of aggregate in sample, V= (A/100) x v: (53/100) x 3.5= 1.855 litres Numerically: V+ V= V Mass of empty glass container, M= 2239 g Mass of glass container + aggregate sample, M=7158 g Mass of aggregate particles, M= M- M=7158g-2239 g = 4919 g Bulk density of aggregates,= 1405.42 g/litres= 1.40542 g/ cm= 1405.42 kg/m Bulk density of aggregates,= 1405.42 g/litres= 1.40542 g/ cm = 1405.42 kg/...