Sieve analysis Introduction Fig. 1. “Mechanical shaker” A sieve analysis (or gradation test) is a practice or procedure used to assess the particle size distribution (also called gradation) of a granular material. The size distribution is often of critical importance to the way the material performs in use. A sieve analysis can be performed on any type of non-organic or organic granular materials including sands, crushed rock, clays, granite, feldspars, coal, soil, a wide range of manufactured powders, grain and seeds, down to a minimum size depending on the exact method. Being such a simple technique of particle sizing, it is probably the most common. Aggregates have definite effects on the properties of concrete and their selection is important to the effective use of concrete. Sieve analysis is performed on fine and coarse aggregates in order to determine the particle size and the distribution of aggregates in specified amount of sample. A sieve analysis can be performed on any type of non-organic or organic materials including sands, crushed stones, crushed gravel, clays, coil and soil. Fig. 2. “Balance with a sample on it” Objectives The sieve analysis determines the grain size distribution curve of soil sample by passing them through a stack of sieves of decreasing netting opening sizes and by measuring the weigh tretamine on each sieve. determine the particle size and the distribution of aggregates in specified amount of sample .And to Select sieves I.S specifications and perform sieving, Obtain percentage of soil retained on each sieve, and Draw graph between log grain size of soil and % finer. Methodology and Procedures A sample of fine aggregates were taken and measured by the balance. Its weight was about 2002g. The sample was put on the stack of sieves, in descending order, starting with the sieve opening of diameter 4.75mm till the smallest sieve of diameter 150μ or 0.15mm then a pan. The stack of sieves was put on the mechanical shaker to separate the sizes of the fine aggregates. The weight retained on each sieve and the pan was measured. Weigh each empty sieve and the pan. Nest the suitable sieves in order of decreasing size of opening from top to bottom. Place the pan at the bottom of the set. Place the sample on the top sieve. Place the lid, and agitate the sieves in the mechanical shaker for about 5 minutes, or long enough to distribute all the aggregate. . Weigh the sieves with the material retained. Determine the weight retained in each sieve. The total weight of the material after sieving should check closely with the original weight of the sample. Calculate the percentage coarser than and the percentage passing, and draw the graph. 22 April 2017 AY 2016-2017 Results and graph Total sample weight : 2002 gm Sieve number Opening (mm) Mass Retained (gm) Total mass Retained Passing Cumulative Ret. (%) Re. Percentage 4 10 20 40 60 80 100 200 4.75 2.36 1.25 0.6 0.3 0.15 0.075 pan 110 169.5 159 707 728 88 25.5 15 110 279.5 438.5 1145.5 1873.5 1961.5 1987 ------------ 1892 1722.5 1563.5 856.5 128.5 40.5 15 - 94.5055 86.039 78.0969 42.7822 6.41858 2.0229 0.7492 ------ 5.4945 10.961 21.9031 57.2178 93.558142 97.9771 99.2508 Sieve Analysis 100 90 80 passing percent % 70 60 50 40 Sieve Analysis 30 20 10 0 10 1 0,1 0,01 Sieve Diameter 1. Uniformity coefficient =D60/D10 = 0.85/0.3 =2.833 2. Coefficient of gradient = (D30)2/D10*D60 = 0.652 / 0.85*0.3 = 1.658 > 1 (well graded ) 22 April 2017 AY 2016-2017 IN Conclusion Finally, the goal of sieve analysis test is to determine the properties of the aggregate and to see if it is appropriate for various civil engineering purposes such as selecting the appropriate aggregate for concrete mixes and asphalt mixes as well as sizing of water production well screens. And, to advantages of the sieve analysis include easy handling, low investment costs, precise and reproducible results in a comparably short time and the possibility to separate the particle size fractions. 22 April 2017 AY 2016-2017 Liquid limit Introduction Liquid limit (LL) is the water content inside the soil in percent, that makes the sample in a liquid state. This test is performed on clay samples. The objective behind it is to compare it between the code’s limitation to classify the sample. This can help to choose the suitable recommendation to the foundation used in the building. Equipment 1-Casagrande’s liquid limit device Fig 1 Casagrande’s liquid limit device 2-Grooving tool with gage length of 13 mm Fig 2 Grooving tool 22 April 2017 AY 2016-2017 3-4Cups 4-Spatula 5-Water bottle filled with distilled water Fig 3 Pouring distilled water on the clay 6-Dry oven set at 110 °C 7-Weighing balance 22 April 2017 AY 2016-2017 Fig 4 Balance with the cup and a sample on it Procedures Place prepared sample in the cup of the liquid limit device Draw the grooving tool through the sample along the symmetrical axis of the cup, holding the tool perpendicular to the cup. Lift and drop the cup at a rate of around 2 drops per second Record the number of drops required to make the parts of the soil sample come into contact for about 13 mm length Remove the slice of soil and place it into the cup to determine its water content Repeat these steps with another samples (around 4) Liquid limit table Sample # Number Mass of of blow cup (gm) Mass of Mass of cup & wet cup & dry Mass of Mass of Water dry soil water content % soil (gm) soil (gm) (gm) 1 37 17.5 86.5 70 52.5 16.5 31.4 2 40 16 56 44.5 28.5 11.5 40.3 3 24 20 72 58 38 14 36.8 4 22 17 68.5 65 48 3.5 7.29 22 April 2017 AY 2016-2017 Graph Liquid limit WC(%) 90,0% Liquid limit 60,0% 30,0% 100 10 1 Conclusion By altering the water content of the soil and repeating the foregoing operations, obtain at least 4 readings in the range of less than and more than 25 blows. Don’t mix dry soil to change its consistency. Liquid limit is the water content percentage at 25 blows, which in this case was 22 April 2017 AY 2016-2017 Plastic limit test Introduction Fig. 1 the sample used in test The plastic limit of soil is water content of the soil below which it ends to be plastic. It begins to crumble when rolled into threads of 3mm diameter and presented as a percentage of the weight of the oven dried soil at which the soil can be rolled. Objectives The aim of this experiment is to determine the samples of soil which the limit between plastic state and semi plastic state. The plasticity index of a soil is the numerical difference between the liquid limit and the plastic limit. It is the moisture content at which the soil is in a plastic state Equipment 1. Ground glass plate about 200mm x 150mm 2. Metallic rod 3mm diameter and 100mm long 3. Oven 4. Spatula 5. Vernier caliper 6. balance 22 April 2017 AY 2016-2017 Fig. 2 the equipment used in plastic limit test Procedure Take about sample of the soil and roll it with fingers on a glass plate. The rate of rolling should be between 80 to 90 strokes per minute to form a 3mm diameter. If the diameter of the rolled sample is less than 3mm, without any cracks appearing, it means that the water content is more than its plastic limit and need to reduce water content by rolling it again Repeat the process of alternate rolling and kneading until the thread crumbles Then we measure specimen weight Repeat the procedures three times with fresh samples of plastic soil each time Putting the specimens in oven for 24 hours Then calculate the plastic limit Fig.3 sample after dried in oven 22 April 2017 AY 2016-2017 Calculations Sl. No. 1 Observations and Calculations Sample .1 Sample .2 Sample .3 Sample.4 Mass of empty container (m1) 17 18 19 20 2 Mass of container + wet soil (m2) 18.5 19.5 20 21.5 3 Mass of container + dry soil (m3) 18 19 19.5 21 4 Water content = (m2- m3/ m3-m1) *100% 0.5 0.5 1 0.8 The plastic limit = 57.1% Conclusion The plastic limit is the water content at which a soil becomes too dry to be plastic. It used together with the liquid to determine the plasticity index and It is recognized that the results are subject to the judgment of the operator, and that some variability in result will occur. It is convenient to carry out the test on a portion of the prepared material and through this experiment, we managed to achieve the objective of this lab that is to measure the plastic limit to the given soil sample 22 April 2017 AY 2016-2017