RICE HUSK ASH ON CEMENT CONCRETE

  

       RICE HUSK ASH (RHA) PROPERTIES:

v    SPECIFIC GRAVITY:

WEIGHT OF EMPTY PYCNOMETER (M1)                                 : 324.5g

WEIGHT OF PYCNOMETER + RICE HUSK ASH (M2)             : 355.9g

WEIGHT OF PYCNOMETER + RHA + WATER (M3)                : 856.3g

WEIGHT OF PYCNOMETER +WATER (M4)                              : 871.7g

SPECIFIC GRAVITY OF RHA : M2-M1 / (M2-M1)-(M4-M3)

                                                   = 1.96        

SPECIFIC GRAVITY OF RHA = 1.96

v    BULK DENSITY :

EMPTY WEIGHT OF CALIBRATED CONTAINER           : 47g

WEIGHT OF CONTAINER + RHA                                                 : 96.6g

VOLUME OF CONTAINER                                                 :100 cm³

BULK DENSITY OF RHA     = (96.6-47) / 100

                                                = .496 g/cm³

                                                = 496 kg/m³

BULK DENSITY OF RHA : .496 g/cm³ i.e 496 kg/m³

v    FINENESS OF RHA:

MASS OF SAMPLE OF RHA                      : 100g

MASS PASSING 90 MICRON SIEVE        : 40g

FINENESS OF RHA  = 60%

High value due to ineffective grinding of sample.

EFFECT ON CEMENT AND CONCRETE:

v    WORKABILITY:

Ø SLUMP TEST

0-25mm SLUMP                                     LOW WORKABILITY

25-75mm SLUMP                                   MEDUIM WORKABILITY

75-100mm SLUMP                                 HIGH WORKABILITY

·        FOR 43 GRADE SANKAR OPC,0% RHA :

WATER CONTENT %	SLUMP (mm)
0.45	0
0.55	42
0.60	95

HIGH WORKABLILITY AT 0.60 WATER CONTENT

·        FOR SAME WATER CONTENT,AT DIFFERENT REPLACEMENT %

% REPLACEMENT	WATER CONTENT %	SLUMP (mm)
0	0.50	13
10	0.50	5
20	0.50	3
30	0.50	0
40	0.50	0

WORABILITY OF THE MIX REDUCES GREATLY AS THE PERCENTAGE REPLACEMENT OF RHA INCREASES.

·        VARYING WATER CONTENT ACCORDING TO STUDY PROVIDED ON LITERATURE

% REPLACEMENT	WATER CONTENT	SLUMP (mm)
0	0.50	13
10	0.54	10
20	0.55	7
30	0.56	0
40	0.57	0

VARYING THE WATER CONTENT SLIGHTY ACCORDING TO DATA GIVEN IN STUDY DOES NOT GIVE WORKABLE MIX.

·       TO FIND HIGH WORKABILITY WATER CONTENT FOT DIFFERENT PERCENTAGE (%) REPLACEMENTS.

§  10 % REPLACEMENT

WATER CONTENT	SLUMP (mm)
0.54	10
0.50	25
0.65	40
0.70	100

0.70 WATER CONTENT REQURED FOR HIGH WORKABLE MIX.

§  20 % REPLACEMENT

WATER CONTENT	SLUMP (mm)
0.55	7
0.60	13
0.65	25
0.70	42
0.75	60
0.80	86

0.80 WATER CONTENT REQUIRED FOR HIGH WORABLE MIX.

§  30 % REPLACEMENT

WATER CONTENT	SLUMP
0.56	0
0.60	6
0.65	14
0.70	21
0.75	40
0.80	59
0.85	82

0.85 WATER CONTENT REQUIRED FOR HIGH WORKABILITY MIX.

§  35 % REPLACEMENT

ACCORDING TO STUDY PROVIDED IN DATA MAXIMUM STRENGTH IS ACHIEVED AT 35 % REPLACEMENT OF RHA.

WATER CONTENT	SLUMP (mm)
0.60	5
0.65	13
0.70	17
0.75	30
0.80	55
0.90	80

0.90 WATER CONTENT IS REQUIRED TO GET A HIGH WORAKABLE MIX THAT PROVIDES MAXIMUM STRENGTH.

A HIGHLY WORABLE MIX AT 40% REPLACEMENT TEST NOT CARRIED OUT AS IT WOULD NOT BE TO GET DUE TO HIGH WATER CONTENT OF PRECEDING REPLACEMENTS.

v    NORMAL CONSISTENCY.

§  FOR 43 GRADE OPC .

WATER CONTENT	INITIAL READING	FINAL READING	HT. NOT PENETRATED.(mm)
0.30	0	9	9
0.31	0	6	6

NORMAL CONSISTENCY OF 43 GRADE OPC CEMENT=31%

§  10% REPLACEMENT

WATER CONTENT	INITIAL READING	FINAL READING	HT.NOT PENETRATED (mm)
0.31	0	40	40
0.40	0	25	25
0.45	0	0	0
0.42	0	11	11
0.43	0	5	5

NORMAL CONSISTENCY OF 90% OPC, 10% RHA = 43%

§  20 % REPLACEMENT

WATER CONTENT	INITIAL READING	FINAL READING	HT. NOT PENETRATED (mm)
0.43	0	38	38
0.45	0	37	37
0.47	0	35	35
0.49	0	28	28
0.52	0	22	22
0.54	0	18	18
0.55	0	15	15
0.56	0	12	12
0.57	0	10	10
0.58	0	9	9
0.59	0	7	7

NORMAL CONSISTENCY OF 80%OPC, 20%RHA  = 59%

§  30 % REPLACEMENT.

WATER CONTENT	INITIAL READING	FINAL READING	HT. NOT PENETRATED (mm)
0.57	0	38	38
0.59	0	35	35
0.61	0	33	33
0.65	0	25	25
0.67	0	20	20
0.69	0	18	18
0.71	0	16	16
0.73	0	13	13
0.75	0	11	11
0.77	0	8	8
0.79	0	6	6

NORMAL CONSISTENCY OF 70% OPC, 30 % RHA = 79%

v      INITIAL & FINAL SETTING TIME

§  FOR 43 GRADE OPC.

TIME (MINS)	DEPTH NOT PENETRATED (mm)
5	0
10	0
15	0
20	0
25	0.5
30	0.5
35	0.5
40	0.5
45	1
50	1
55	1
60	1
65	2
70	5

INITIAL SETTING TIME              : 70 MINS

FINAL SETTING TIME                 : 135 MINS

§  10 % REPLACEMENT.

TIME (MINS)	DEPTH NOT PENETRATED (mm)
5	0
10	0
20	0
30	0
40	.5
50	1
60	1
80	2
100	3.5
110	4
120	5

INITIAL SETTING TIME : 120 MINS

FINAL SETTING TIME   : 300 MINS

§  20 % REPLACEMENT.

TIME (MINS)	DEPTH NOT PENETRATED (mm)
10	0
20	0
30	0
40	0
50	0
60	.5
80	.5
100	1
120	2.5
140	3
160	4
170	4.5
180	5

INITIAL SETTING TIME : 180 MINS

FINAL SETTING TIME    : 480 MINS

§  30 % REPLACEMENT

TIME (MINS)	DEPTH NOT PENETRATED (mm)
10	0
20	0
30	0
40	0
60	0
80	.5
100	1
120	1
140	1.5
160	2
180	3
200	3
220	3.5
230	4
240	4.5
250	5

INITIAL SETTING TIME : 250 MINS

FINAL SETTING TIME    : >8 HOURS