Chemical Composition and Physical Characteristics of Rice Husk Ash Blended Cement

Raheem, Akeem Ayinde; Kareem, M.A.

doi:10.4028/www.scientific.net/jera.32.25

Cited by 55 publications

(41 citation statements)

References 27 publications

(41 reference statements)

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“…The reasons for this trend may be attributed to the finer particles of BA relative to RHA that replaced the soil particles. This phenomenon was previously reported [16]. In addition, the configuration of the voids of the soil following mixing with admixtures might have enabled more particles of BA to achieve the maximum dry density.…”

Section: Optimum Moisture Content (Omc)supporting

confidence: 73%

“…This deficiency can be overcome by adding another admixture that has a high content of CaO. Probably the best admixture to be used for such purpose is cement, which has CaO content of more than 60% [16] and is readily available worldwide.…”

Section: Saturated Hydraulic Conductivitymentioning

confidence: 99%

“…The use of pozzolanic materials for stabilisation purposes abound in the literature [13][14][15][16][17][18]. The pozzolanic materials being used are usually the abundant waste products from human activities in the locality -in an effort to enhance sustainable living.…”

Section: Introductionmentioning

confidence: 99%

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A Comparative Study of the Basic Strength and Hydraulic Properties of Lateritic Soils Stabilized with Rice Husk Ash and Bagasse Ash

Ogundare

Oni

2019

JERR

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The strength and hydraulic properties of lateritic soils stabilized with bagasse ash (BA) and rice husk ash (RHA) were examined in this study. The three lateritic soil samples used in the study were obtained from a borrow pit near the main waste dumpsite in Ado Ekiti, Nigeria. The BA and RHA were obtained locally from the burning of fibrous residue of sugar cane and rice husk respectively. Classification of the soils using AASTHO indicates Soil 1 to be Group A-6 soil, Soil 2 to be Group A-2-6 soil and Soil 3 to be Group A-2-7 soil. In general, the optimum moisture content of the stabilized soils increased with increased content of the admixtures-BA and RHA. The maximum dry density of the stabilized soils decreased with increase in the quantity of BA and RHA. Likewise, the saturated hydraulic conductivity of the stabilized soils decreased slightly with increased content of BA and RHA. The values of the minimum hydraulic conductivity of the stabilized soils were of the order of 10-4cm/s, which are higher than the minimum requirement of 10-7cm/s for soil liners in municipal solid waste landfills. The low pozzolanic characteristics of BA and RHA in the stabilized soils were attributed to the low content of CaO needed to produce CaOH2, which is normally needed to produce pozzolanic reaction products in the presence of water. The characteristics of the modified soils appeared to be influenced by the change in the soil matrix following mixing. Comparison of individual behaviour of BA and RHA in each stabilized soil showed very similar characteristics. It was concluded that another modifier such as cement that has a high content of CaO should be added to the stabilized soils for the full pozzolanic potentials of BA and RHA to be realised.

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Section: Optimum Moisture Content (Omc)supporting

confidence: 73%

Section: Saturated Hydraulic Conductivitymentioning

confidence: 99%

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A Comparative Study of the Basic Strength and Hydraulic Properties of Lateritic Soils Stabilized with Rice Husk Ash and Bagasse Ash

Ogundare

Oni

2019

JERR

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“…The silica content of RHA employed in this study was 81.28 % with literature ranging between 77-94 % [25]. The second and third main constituents of RHA are Phosphorus (V) oxide and Potassium of 5.73 % and 4.02 % which fell within the range of 3-7 % and 4-10% respectively [51].…”

Section: Resultsmentioning

confidence: 76%

A Study on Ordinary Portland Cement Blended with Rice Husk Ash and Metakaolin

Olubajo

Makarfi

Ibrahim

et al. 2020

PoS

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This paper tries to investigate the effect of replacing Ordinary Portland cement (OPC) with Metakaolin (MK) and Rice husk ash (RHA) on the physicomechanical properties such as consistency, setting times, soundness and mortar compressive strength of ternary cement up to 40 % cement replacement. The soundness of the blended cement pastes and compressive strength of the blended mortars were conducted using Le Chatelier apparatus and Tonic Technic compression machine while the initial and final setting times were conducted on the blended cement paste using Vicat apparatus.. Nineteen ternary cement mortars were prepared to comprise of OPC, RHA MK at different proportions and tested at 2, 7, 28 and 60 days. Results indicated that as RHA was gradually increased up to 25% at constant MK content, the volume expansion of the ternary cement paste increased gradually. On the other hand, as MK was increased from 5-25% at constant RHA, the volume expansion diminished. The water consistency of ternary cement paste experienced a variation as MK was increased up to 25 wt% at constant RHA up to 10 wt%. However, at 10 wt% constant RHA as MK was increased the water demand gradually increased. Similarly, an increase in RHA at constant MK increased the water demands of the ternary blends. An increase in RHA from 5-25 wt% at 5-25 wt% constant MK resulted in acceleration in the initial and final setting times of cement blends. These accelerations could be attributed to the pozzolanic activity leading in shorter setting time. Whereas a series of accelerations and retardations of both setting times were experienced as the MK was increased from 5-25 wt% at 5-25 wt% constant RHA. It was observed that increment in the MK or RHA up to 10 wt% at constant RHA/MK up to 10 wt% resulted in improved mortar compressive strength of the ternary blend in comparison with control. This improvement was attributed to the high silica/alumina contribution to the matrix by MK inclusion, the C/S ratio in the cement matrix and RHA pozzolanic reactivity despite its unburnt carbon. All mortar compressive strength of the cement blends and control experienced an increase as the curing days were lengthened from 2 to 60 days. The enhanced strength compared with the control especially beyond 28 days could be attributed to the slow pozzolanic reaction resulting from the formation of additional CSH and CAH from the interaction of the residual CH and the silica available in the MK and RHA. The best compressive strength at 60 days was obtained at cement replaced with 15 wt% and 20 wt% at MK 5 wt% RHA producing a mortar compressive strength of 40.5 MPa.

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“…Increase in standard consistency with increase in RHA addition can be attributed to the high fineness and surface area of RHA. According to Raheem and Kareem [36], RHA is considered hygroscopic; hence, more water is required for wetting the particles as the total specific surface of the particle increases.…”

Section: Standard Consistencymentioning

confidence: 99%

Physicochemical Properties of Hydrated Portland Cement Blended with Rice Husk Ash

Marangu

M’thiruaine

Bediako

2020

Journal of Chemistry

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In the presence of significant quantities of carbon dioxide (CO2) and elevated temperatures in the atmosphere due to climate change, cement-based materials are susceptible to carbonation. Blended cements are more prone to carbonation attack than Portland cement. There is a need to evaluate the carbonation resistance of blended cements in a carbonation-prone environment. This paper presents experimental findings obtained from an evaluation of carbonation resistance tests on Rice Husk Ash- (RHA-) blended cement. The blended cement was made by intergrinding of Portland Cement (PC) and RHA to make the test cement (PC-RHA). The RHA dosage in the PC-RHA was varied from 0 to 30% by mass of PC. Pozzolanicity, standard consistency, and setting time tests were conducted on PC-RHA. Mortar prisms measuring 160 mm × 40 mm x 40 mm were separately cast at a water/cement ratio ( w / c ) of 0.50 and 0.60 and cured in water for 2, 7, 14, 28, and 90 days. Compressive strength tests were conducted on the mortar prisms at each of the testing ages. The prepared mortars were also subjected to accelerated carbonation tests in two Relative Humidity (RH) curing regimes, one maintained at an RH greater than 90% and the other between 50–60%. Carbonation resistance of the mixtures was evaluated in terms of the changes in carbonation depth using a phenolphthalein test at the age of 7, 14, 28, and 56 days of curing in a continuous flow of CO2. Compressive strength measurements were also taken during each of the carbonation testing ages. For comparison, similar tests were conducted using commercial PC. The results showed that PC-RHA was pozzolanic while PC was nonpozzolanic. Higher water demand and longer setting times were observed in PC-RHA than in PC. Moreover, there was increased strength development in water-cured samples with increased curing duration. Carbonation results indicated that there was a marked increase in carbonation depth with increased dosage of RHA in PC-RHA binders, increased duration of exposure to CO2, and decreased RH (RH between 50–60%). PC-RHA binders exhibited lower carbonation resistance than PC. In conclusion, for mortars at any w / c ratio, carbonation resistance decreased with increase in RHA dosage and increased w / c ratio.

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Chemical Composition and Physical Characteristics of Rice Husk Ash Blended Cement

Cited by 55 publications

References 27 publications

A Comparative Study of the Basic Strength and Hydraulic Properties of Lateritic Soils Stabilized with Rice Husk Ash and Bagasse Ash

A Comparative Study of the Basic Strength and Hydraulic Properties of Lateritic Soils Stabilized with Rice Husk Ash and Bagasse Ash

A Study on Ordinary Portland Cement Blended with Rice Husk Ash and Metakaolin

Physicochemical Properties of Hydrated Portland Cement Blended with Rice Husk Ash

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