The Use of Rice Husk Improving the Final Setting Time and Compressive Strength of Concrete

In this project we are partially replaced the Cement with Rice Husk Ash. So the different types of test are performed.

1. FINENESS TEST OF CEMENT AND RICE HUSK ASH

   In this method the test sample material (Cement and Rice Husk Ash) 800 gm, IS: 90 micron sieve and sieve shaker are used to find the percentage weight of residue over the total sample reported for 15minutes. The percentage residue should not exceed 10%.

   Fig.3:- 90 micron sieve Fig.4:- Sieve Shaker

   Table 5: Particle size analysis

   Fineness Test	Cement	10% Replacement of cement by RHA
   For 15min	Weight of residues = 2.12%	Weight of residues = 3.85%

2. CONSISTENCY TEST OF CEMENT AND RICE HUSK

   ASH

   In consistency test of 300gram material are used and vicat apparatus conforming to IS:5513-1976, balance of capacity 1kg and sensitivity to 1gram, Gauging trowel conforming to IS: 10086-1982, and plunger.

   Fig.3:- Mixing & filling of cement paste in mould

   Fig.5:- consistency test of cement

   Table 6: Value of cement and cement + 10% RHA in consistency test

   Consistency Test	Cement (300gram)	10% Replacement of cement by RHA (270gram cement + 30gram RHA)
   Weight of water added standard consistency (%)	30%-32%	38%

3. INITIAL SETTING AND FINAL SETTING TIME OF CEMENT AND RICE HUSK ASH

   For this test Vicat apparatus, Needle and stop watch is used. Take 300 gm of cement and (270gm cement + 30gm RHA) in a pan. For initial setting and final setting time of cement and RHA.

   Fig.6:-Initial Setting Time Fig.7:- Final Setting Time

   Table 7: Value of Initial and Final Setting Time

   Setting Time	Cement	10% Replacement of cement by RHA
   Initial Setting Time	37min	48min
   Final Setting Time	9 hrs and 10min	6hrs and 40min

4. COMPRESSIVE STRENGHT TEST OF CEMENT MORTAR AND RICE HUSK ASH

In Compressive test 7.05cm cubes moulds, mixing tools for mortar, vibrator, and compressive testing machine are used. Test should be conducted for 3 cubes and report the average value as the result for 3day, 7day and 28day compressive strength.

Fig 8:- Compressive strength testing machine Table 8: Value of Compressive Strength in different days

RESULT AND DISCUSSION

1. The physical property of RHA that influence the activity in gaining strength is its fineness. RHA required having equal or finer than OPC for its good cementing efficiency. The fineness of the 43 grades OPC in this research are found to be 2.12% residue on 90 micron sieve size respectively. Fineness of RHA is found to be 3.85% This shows that RHA is of almost equal size to cement particles. Thus, it is expected to have appreciable influence on the strength development on concrete.

2. Variation of setting time (IST) is increased & final setting time is decreased with increasing RHA content. This behavior may be due to the low rate of hydration in the paste containing RHA. Variation of normal consistency for different grade of OPC using different percentage of RHA. The normal consistency of 43 grade cement is higher by 9% as compare to that of 33 grade cement. The slump and compacting factors test decrease upon the inclusion of RHA as partial replacement of OPC. Thus, it can be inferred that to attend the required workability mixes.

   • The requirement of initial setting time of cement should be more, and cement+ 10% RHA has comparatively more than the cement.

   • The requirement of final setting time of cement should be less, and cement+ 10% RHA has comparatively less than the cement.

     Table 9: Comparison chart of setting time

     Setting Time	Cement	Cement + 10%RHA
     Initial Setting Time(IST)	37min	48min
     Final Setting Time (FST)	540min(9hr and 10min)	400min (6hr and 40min)

     600

     500

     400

     0

     IST (min)

     FST (min)

     Cement

     +10% RHA

     300

     200

     100

     Cement

     Graph 1:- Variation of Setting Time

3. The compressive strength of concrete in all grades of OPC at early age is significantly higher than that of concrete produced with RHA. It was also observed that compressive strength continued to increase with age but decrease with RHA contents in all grade of OPC.

The number of Test taken with number of variation out of which following result with 10% replacement of cement with RHA for 3 day and 7 day of curing proved as a most economical and having good compressive strength.

1. N/mm2 and 14.88 N/mm2 respectively.

   Table 10: Value of compressive strength in different day

   Compressive Strength	Cement	C + 10% RHA
   3 day	9.46 N/mm2	9.05 N/mm2
   7 day	15.08 N/mm2	14.88 N/mm2
   28 day	37.96 N/mm2	37.04 N/mm2

   40

   30

   20

   10

   Cement

   C + 10% RHA

   0

   3 Day 7 Day 28 day

   Graph 2:- Variation of compressive strength

   COST ESTIMATION

   • Cost of 1bag of cement = 300

   • Weight of 1 bag cement = 50 kg

   • Replacement of cement = 10%

   • Received weight = 5kg

   • Rate of 5kg cement = 30 /- (Rs.) Hence we are saving 30/- in per bag of cement.

CONCLUSIONS

Based on the experimental results obtained in the study, the following conclusions may be drawn:-

• This method can solve two major problems i.e. higher concrete cost & managing agricultural waste.

• By using 10% rise husk in concrete mixture, final setting time reduced with no other effect in overall compressive strength of the mixture.

• Rice Husk Ash is easily available agricultural waste it gives durable concrete.

• By using this mixture net weight of the concrete gets reduced.

From all the tests performed and result interpretive it can be concluded that the partial replacement of cement with RHA is advantageous and adoptable.

REFERENCES

1. G.A. Habeeb, M.M. Fayyadh Rice Husk Ash Concrete: the Effect of RHA Average Particle Size on Mechanical Properties and Drying Shrinkage Australian Journal of Basic and Applied Sciences, 3(3): 1616-1622, 2009 ISSN 1991-8178

2. Abu Bakar et al. Malaysian Rice Husk Ash Improving the Durability and Corrosion Resistance of Concrete www.crl.issres.net Vol. 1 (1) March 2010

3. E. B. Oyetola and M. Abdullahi The Use of Rice Husk Ash in Low – Cost Sandcrete Block Production Leonardo Electronic Journal of Practices and Technologies ISSN 1583-1078 Issue 8, January-June 2006 p. 58-70

4. Alireza Naji Givi et al. Contribution of Rice Husk Ash to the Properties of Mortar and Concrete http://www.americanscience.org

5. Satish D. Kene t al. Assessment of Concrete Strength using Flyash and Rice Husk Ash International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 Vol.1, Issue 3, pp.524-534

6. Sudisht Mishra, Prof(Dr.) S.V. Deodhar Effect of Rice Husk Ash on Cement Mortar and Concrete

7. Dr. J.N. Jha and K.S. Gill Effect of Rice Husk on Cement Concrete