Investigation On The Characteristics Of Cornstalk Ash Blended Cement

3.1 Experiment Site
    The experiment was carried out at Lafarge cement both the tests for the physical and chemical analysis. The corn stalk ash was obtained by burning the stalk in an enclosed brick oven of corn stalk and it was burnt at a temperature of 1200°C into ash. Figure 3.3 shows the snapshots of the corn blended ash.

The method used to produce the studied corn stalk ah blended cement was as follows: the corn stalk ash was mixed with Lafarge Cement, an example of Ordinary Portland Cement (OPC) inside a mixer, and they were mixed as such up to a homogeneous mix obtaining.
3.2 COMPRESSIVE STRENGTH
     Ordinary cement was replaced with Corn stalk ash (CSA) at 10% and 20% by weight of cement, with concrete cubes without CSA serving as control experiment. The mix ratio to be used is 1:3. Water/Cement ratio is 0.5.
The specimens was prepared for compressive strength, density and durability (water absorption and abrasion) tests using concrete cube moulds. The specimens were casted and well compacted, with the outside surfaces cleaned. After casting, the specimens were placed in the curing room at temperature of 27 + 20C and relative humidity of not less than 90% for 24 hours.
Compressive strength and density tests were carried out on each of the specimens after curing periods of 7, 14, 21, and 28days. Mould size  for cube in flexural analysis was 40,40 by 40mm and mould size for compressive strength was 40mm x 40mm x 40mm.
3.3 CHEMICAL ANALYSIS
30g of CSA was weighed into the drying dish and dried to a consant weight of 0.01g in the oven, it was allowed to cool in the dessicator. CSA was thoroughly blended with spatula and 0.8g of stearic acid was weighed into sample dish,25.0g of blended CSA was weighed into it and then transferred into gyro-mill grinding dish with proper clamping ensured. The mill was covered and a 90mins timer was set for slurry, after grinding for the set time, the dish was removed from the mill and CSA was gently transferred into a clean paper using the brush.
1 teaspoon of stearic acid was placed in the pellet cup and CSA was thoroughly blended and about 2teaspoon of CSA was spread in the pellet contaning stearic acid and the pressing program was selected. The cross bar was opened and tool cover removed, the pellet cup was introduced into the recess of the pressing machine cylinder, and the pellet die was introduced to cover the sample with it shinning, the cross bar was closed. After pressing process, the cross displayed was opened and the cross bar along side tool cover and the pressed pellet was ejected. it was then labeled and transferred into X-ray analyzer for analysis.
3.4 PHYSICAL ANALYSIS
Expansion
•    To check for the presence of lime in cement. Cement was mixed with adequate quantity of water and put into a mould and it was left there for 24hours.when it was dry, it was measured and placed in a bath tub at a temperature of 100℃ and left to cool after which the new measurement was taken to check for the difference in expansion.
Residue
•    Alpan sieve machine was used to check the grindability of  the blended cement. After sieving, particles was checked for on the sieve and was measured.
Surface Area
•    Acmel machine was used to check for the fineness of the blended cement to discover if it is light or heavy in other to have a free flow for ventilation mill to bag it.
Materials used
    Sand
    Granite
    Cornstalk
    Cement
    Water