Received Date: 17 June, 2017 Accepted Date: 22 August, 2017
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The aim of this study is to examine the performance of concrete induced with various percentage of palm shell replaced as coarse aggregate. Utilising Palm Shell in concrete production solves the problem of disposing this solid waste and also helps in conserving natural resources. A total of 5 percentages (20%, 40%, 60%, 80%, 100%) of varying coarse aggregate replacement were fabricated and tested. The compressive, tensile, and flexural characteristics of palm shell concrete is studied and compared to that of control concrete specimens. The optimum percentage of replacement was found to be within the range of 20% to 40%.
Palm shell, Oil palm shell
Utilization of wastes from agriculture in concrete production has been studied for many years. The amount of agricultural waste discharged into the environment is increasing over years in most of the agricultural countries. Henceforth research has been carried out for past few decades on utilization of these agricultural wastes as an alternative material in concrete production. Research conducted on Oil Palm Shell Concrete shows that (Shafigh, et al., 2012). The ratio betweentensile and compressive strength obtained for Oil Palm Shell concrete is lesser than conventional concrete. However, it is comparable with Light Weight Aggregate Concrete made with Light Weight Aggregate of similar grade (Teo, et al., 2006). The bond property of Oil Palm Shell Concrete is comparable with Light Weight Aggregate Concrete with artificial Light Weight Aggregate of an similar grade (Teo, et al., 2006; IS: 12269-1987; IS 83:1970). Beams made with OPS concrete expressed good ductility characteristics.
Borassusflabellifer also commonly known as Palmyra palm is native to the Indian subcontinent and Southeast Asia. It is reportedly naturalized in Pakistan, Socotra, and parts of China. The fruit of Palmyra palm measures from 10cm to 18cm in diameter, has a husk which is black in color, and they hang in clusters. The thin yellowish brown skin which covers the fruit of Palmyra palm hardens to form the shell as the fruit ripens. Palmyra palm shell is used as fuel for brick kilns and as fire wood for cooking by local people. Palmyra palm shell is fibrous in nature resulting in high ductility values and light weight. It is not easily degradable and burning it will result in serious environment hazards like huge ash content, air pollution and health problems. Also during production of concrete huge amounts of natural resources were utilized, so replacing materials in concrete can help in conserving natural resources. As Palmyra palm shell is available in our region, we are replacing coarse aggregate in concrete with Palmyora palm shell. The testing methods and test results obtained for Oil Palm shell concrete were referred in this study (Mannan and Ganapathy, 2002; Mannan, et al., 2006).
Ordinary Portland Cement is one of the most commonly used types of Portland cement. In this project Ordinary Portland Cement of grade 53 was used. The cement satisfied the requirement of IS: 12269-1987 specification. The fine aggregate used in the experimentation conforms IS: 383- 1970 specifications and it is from Zone II. The coarse aggregate used in the experimentation were about 12.5mm size and tested as per IS: 383-1970 specifications. Palmyra palm shell is collected, dried and is cut into small pieces of required size (12.5mm). (Figure. 1-3) shows the conversion of palm shell.
Preliminary tests were conducted on the materials used in this study according to Indian Standard codes. Table 1 shows the results of the tests on various materials. From the results it was inferred that the specific gravity of palm shell was found to be 57.44% less than the specific gravity of coarse aggregate which results in light weight nature of palm shell and the aggregate impact value of Palm shell is found to be 81% less than that of coarse aggregate which shows its ductility behavior. Mix ratio referring IS10262:2009 for M30 grade concrete is found to be 1.65:1.8.
|Initial setting time||32 min|
|Final setting time||Ã¯Â¿Â½? 480 min|
|Fine aggregate||Specific gravity||2.6||383-1970|
|Coarse aggregate||Specific gravity||2.82||383-1970|
|Aggregate impact value||17.9%|
|Palm shell||Specific gravity||1.2||383-1970|
|Aggregate impact value||3.38%|
Table 1. Preliminary test results
In this study Palm Shell replaced concrete specimens were tested for compressive strength, split tensile strength and flexural strength, the test results were compared with conventional concrete (Shafigh, et al., 2012; Shetty, 2005; Momeen). A total of 104 specimens were casted with 20%, 40%, 60%, 80% and 100% of aggregate replacement. The test results are shown in Table 2.
|Type of concrete||Compressive strength
after 28 days( N/mm2)
After 28 days (N/mm2)
after 28 days (N/mm2)
Table 2. Test results after 28 days of curing
According to IS:516-1959 Cubes of dimensions 100 × 100mm were casted. A total of 54 cube specimens with 20%, 40%, 60%, 80%, and 100% aggregate replacement were casted. Compressive strength of specimens at 7, 14 and 28 days were tested using Universal Testing Machine (UTV) of 100kN capacity. The test results are compared with conventional concrete specimens of similar size are shown in Table 2. From the results it’s inferred that the compressive strength decreases with increases in percentage of palm shell replacement. Compressive strength achieved by 20% and 40% of palm shell replaced concrete after 7 days was found 10% and 12% higher than conventional concrete compressive strengths respectively. Compressive strength after 14 days of curing for 20% and 40% of palm shell replaced concrete was 5.7% and 5% lesser for conventional concrete. Compressive strength after 28 days of curing for 20% and 40% of palm shell replaced concrete was 5.75% and 11.9% less than the conventional concrete respectively. Optimum percentage of replacement was found to be between 20% to 40%. It can be seen in (Figure. 4), there is a gradual drop in the compressive strength after 60% of replacement. 20% of aggregate replaced Palm Shell Concrete showed better results.
Split tensile strength
According to IS: 516-1959 cylinders of dimensions 100 × 200 mm were casted and tested. A total of 54 Palm shell concrete cylinder specimens with 20%, 40%, 60%, 80%, and 100% aggregate replacement were casted. Split tensile strengths of palm shell concrete was tested after 7, 14 and 28 days of curing, using Universal Testing Machine (UTV) of capacity 100kN and the results were compared with the results of conventional concrete specimens of similar size are shown in Table 2. Tensile strength achieved by 20% and 40% of palm shell replaced concrete after 7 days was found 12% and 32% lower than conventional concrete compressive strengths respectively. Tensile strength after 14 days of curing for 20% and 40% of palm shell replaced concrete was 31.75% and 37% lower for conventional concrete respectively. Split tensile strength achieved by 20% and 40% after 28 days of curing was 28.5% and 38% less than the conventional concrete respectively. The optimum percentage of aggregate replacement was found to be within the range of 20% to 40%. In (Figure. 5) the tensile strength follows the same pattern like compressive strength graph.
According to IS:516-1959 beams of dimension 500 × 100 × 100 mm were casted and tested. Palm shell concrete beam specimens with 20%, 40%, 60%, 80%, and 100% aggregate replacement were casted.
The test results are shown in the Table 2. Flexural strength strength after 28 days of curing for 20% and 40% of palm shell replaced concrete was 41% and 33% lesser than conventional concrete respectively (Figure. 6).
According to the mix design used in present study, cost comparison for coarse aggregate and palm shell is tabulated below in Table 3. Though palm shell replacement in concrete provided satisfactory results in strength aspect, there is a noticeable difference in cost aspect. So by cost aspect Palm shell replaced concrete has an advantage over conventional concrete.
|Description||Coarse aggregate||Palm shell|
|Cost per kg||0.58 Rs||0.20 Rs|
|Number of kg per cubic meter of concrete||873.55 kg||374.1 kg|
(Direct and indirect cost)
|Total cost||506.6 Rs||274 Rs|
Table 3. Cost comparison
Based on the comparison of test results, the following conclusions were made:
1. Based on initial tests performed, Palm Shell has good potential to be used asreplacement for coarse aggregate as light weight aggregate in concrete.
2. Palm shell concrete is found 10% lighter than the conventional concrete.
3. Optimum percentage range of replacement of palm shell lies between 20% to 40%, which provided equivalent strength as that of the conventional concrete.
4. Cost of palm shell is found to be 46% lesser than the cost of coarse aggregate. So it is economical by reducing the construction cost.