Rice Husk Ash Content Research Articles

Effects of two biomass ashes on asphalt binder: Dynamic shear rheological characteristic analysis

In this work, two kinds of biomass ashes (BA), rice husk ash (RHA) and wood sawdust ash (WSA) were used to modify asphalt binder. Fourier Transform Infrared (FT-IR) Spectroscopy was used to characterize the effects of biomass ashes on chemical properties of asphalt binder. Physical properties, such as dynamic rheological behavior, high temperature storage stability and aging properties of the modified asphalt were investigated. Test results indicated that there is no chemical reaction between asphalt binder and BA. The RHA and WSA particle effect during blending with asphalt binder under physical agitation dominated the modification. Compared with WSA, RHA showed better effect in improving physical properties of modified asphalt binder. The storage stability tests indicated that the asphalt binder modified with RHA and WSA is stable when ash content is less than 20%. With the enhancement of the content of RHA and WSA to asphalt binder, viscosity, complex modulus and rutting factor (G*/sinδ) of modified asphalt binders increased rapidly at high temperatures. As a consequence, the deformation resistance of these modified binders at high temperatures was especially improved. RHA and WSA can be considered as asphalt modifiers which were more helpful for the improvement of rutting resistance.

Compaction characteristics of fine grained soil and rice husk ash mixture

This study presents the compaction characteristics of fine grained soil and rice husk ash (RHA) mixture. Three types of fine grained soils viz., montmorillonite clay, kaolinite clay, and one local soil has been used in the present study. From the compaction tests results it is observed that with increase in RHA content (0–30%) maximum dry density (MDD) decreases and also optimum moisture content (OMC) increases irrespective of types of fine grained soil. Based on the experimental data, a number of linear regression models have been developed to estimate MDD and also OMC of fine grained soil and RHA mixture. Empirical models also presented to estimate dry density in terms of water content of dry side of optimum or water content of wet side of optimum, compaction energy, RHA content, and also specific gravity of fine grained soil and RHA mixture. The above models may be useful for the field engineers within the range of compaction energy from 300 kJ m−3 to 2700 kJ m−3, RHA content from 0%–30%, specific gravity of fine grained soil and RHA mixture from 2⋅311–2⋅750, and OMC for soil from 16⋅8%–37⋅0%.

Strength and Some Durability Properties of Concrete Containing Rice Husk Ash Produced in a Charcoal Incinerator at Low Specific Surface

Strength and some durability properties of concrete containing rice husk ash (RHA) predominantly composed of amorphous silica at a specific surface of 235 m2/kg produced using a charcoal incinerator were determined. The maximum ordinary Portland cement (OPC) replacement with the RHA increased with increase in water/binder (w/b) ratio of the concrete mixes. The results show that 15 % OPC could be substituted by the RHA without strength loss at w/b ratio of 0.50. The split tensile strength generally increased with increase in RHA content for the mixes.

Using wood fiber waste, rice husk ash, and limestone powder waste as cement replacement materials for lightweight concrete blocks

This work presents a parametric experimental study, which investigates the effects of partial replacement of Portland cement by wood fiber waste (WFW), rice husk ash (RHA), and limestone powder waste (LPW) for producing a lightweight concrete block as a building material. Some of the mechanical and physical properties of block materials having various levels of WFW, RHA, and LPW are studied. The compressive strength of the concrete blocks due to the filler effect decreased with increasing cement replacement. However, the results show the effect of 25wt% replacement of RHA and LPW with Portland cement do not exhibit a sudden brittle fracture even beyond the failure loads, indicates high energy absorption capacity, reduce the unit weight dramatically. As expected, the increase of the RHA content induced the reduction of bulk density of the concrete blocks. Statistical analysis showed that the interactions of above-mentioned variable parameters were significant on both mechanical and physical properties at 5% confidence level. The optimum replacement level of WFW, LPW, and RHA was 25% by weight; this replacement percentage resulted in good physico-mechanical properties. Recycling of WSW, RHA, and LPW as promising raw material supplements appears to be viable solution not only to the environmental problem but also to the problem of the economic design of buildings.

An Artificial Neural Networks Model for Predicting Permeability Properties of Nano Silica–Rice Husk Ash Ternary Blended Concrete

In this study, a two-layer feed-forward neural network was constructed and applied to determine a mapping associating mix design and testing factors of cement–nano silica (NS)–rice husk ash ternary blended concrete samples with their performance in conductance to the water absorption properties. To generate data for the neural network model (NNM), a total of 174 field cores from 58 different mixes at three ages were tested in the laboratory for each of percentage, velocity and coefficient of water absorption and mix volumetric properties. The significant factors (six items) that affect the permeability properties of ternary blended concrete were identified by experimental studies which were: (1) percentage of cement; (2) content of rice husk ash; (3) percentage of 15 nm of SiO2 particles; (4) content of NS particles with average size of 80 nm; (5) effect of curing medium and (6) curing time. The mentioned significant factors were then used to define the domain of a neural network which was trained based on the Levenberg–Marquardt back propagation algorithm using Matlab software. Excellent agreement was observed between simulation and laboratory data. It is believed that the novel developed NNM with three outputs will be a useful tool in the study of the permeability properties of ternary blended concrete and its maintenance.

Reconstituted Cement Kiln Dust–Rice Husk Ash Stabilization of Reclaimed Asphalt Pavement as Highway Pavement Material

Abstract A large volume of cement kiln dust is generated as a solid waste by-product from the pre-heater by-pass systems during the manufacture of Portland cement clinker. It is disposed of on production sites, and sometimes in landfills. Pavement rehabilitation and reconstruction also generate a large volume of reclaimed asphalt pavement waste that is disposed of along road alignments, and rice husk ash is generated by the combustion of rice husk and disposed of as waste in large quantities in rice mills. This paper presents the results of a laboratory evaluation of the characteristics of reclaimed asphalt pavements stabilized using reconstituted cement kiln dust and rice husk ash waste with a view to determining its suitability for use as a flexible pavement material. The mixtures were subjected to British Standard light (standard Proctor) compactive efforts to determine the compaction characteristics and California bearing ratio. The test results show that the properties of reclaimed asphalt pavement waste improved with reconstituted cement kiln dust–rice husk ash waste treatment. The maximum dry density decreased and the optimum moisture content increased with increasing rice husk ash (RHA) content and decreasing cement kiln dust (CKD) and reclaimed asphalt pavement (RAP) contents in the mixes. Optimum California bearing ratio values of 34.0 % (unsoaked) and 54.0 % (soaked for 24 h) were recorded for 50 % RAP + 50 % (50 % CKD + 50 % RHA) mix. With the potential for time-dependent increases in strength in view, the optimum mixture satisfied durability requirements with insignificant water absorption and can be used as sub-base material in flexible pavement construction. This research provides results of the evaluation of RAP waste stabilized using reconstituted CKD and RHA wastes as highway construction material, as based on California bearing ratio determination. Further work is encouraged to assess the resilient modulus of this material under cyclic load.

Mechanical Behaviors and Chloride Permeability of Rice Husk Ash Concrete

Rice husk ash (RHA) was used as a mineral additive in concrete and replaced the ordinary cement by 0-30% in this study. The fresh concrete properties, compressive strength, split tensile strength, and elastic modulus as well as the chloride permeability of concretes mixed with different RHA contents was tested. The experimental results reveal that the fluidity, the mechanical behaviors and the chloride ion resistance of rice husk ash concrete decrease with the increasing replacement rate of RHA. The particle size of RHA limits its pozzolanic activity, which indicates that the controlled burning temperature and the fineness of RHA have significant impact on the properties of rice husk ash concrete.

RETRACTED ARTICLE: Predicting the effects of nanoparticles on compressive strength of ash-based geopolymers by gene expression programming

In the present work, the effect of SiO2 and Al2O3 nanoparticles on compressive strength of ash-based geopolymers with different mixtures of rice husk ash, fly ash, nanoalumina and nanosilica has been predicted by gene expression programming. The models were constructed by 12 input parameters, namely the water curing time, the rice husk ash content, the fly ash content, the water glass content, NaOH content, the water content, the aggregate content, SiO2 nanoparticle content, Al2O3 nanoparticle content, oven curing temperature, oven curing time and test trial number. The value for the output layer was the compressive strength. According to the input parameters in gene expression programming models, the data were trained and tested, and the effects of SiO2 and Al2O3 nanoparticles on compressive strength of the specimens were predicted with a tiny error. The results indicate that gene expression programming model is a powerful tool for predicting the effect of nanoparticles on compressive strength of the geopolymers in the considered range.

Characteristics of Masonry Blocks Manufactured with Rice Husk Ash (RHA) and Lime

Rice husk is one of major agro-waste material in Sri Lanka. Rice Husk Ash (RHA) is produced by burning Rice husk as fuel in brick kiln. Rice husk ash produced by burning at high temperature contains pozzolanic constituents. In Sri Lanka, cement is extensively used to manufacture masonry blocks, although the cost of cement is high. Because of having highly pozzolanic constituents in RHA, it can be used as a building material, instead of cement, to produce cement sand masonry blocks. It was frequently reported that compressive strength of RHA based blocks increases with increasing the RHA content up to 5% and further addition of RHA causes to decrease in compressive strength. In this study, an attempt is made to increase the utilization of RHA by adding Ca2+ to the mixture. Solid masonry blocks, having the size of 360 mm x 100 mm x 170 mm, were cast with the mix proportion of 1:6 Cement - Sand. Blocks were manufactured in two series. In the first series, RHA was used as addition with respect to weight of cement. In this series, four different RHA contents (i.e., 0%, 5%, 10%, and 15%) were used with constant lime content (10%). In the second series, RHA was used as partial replacement for cement with four different RHA contents (i.e., 5%, 10%, 15% and 20%) with constant lime content (10%).The blocks were tested for 7, 14 and 28 Day compressive strength. With the presence of lime (10%), the optimum 28 Day compressive strength was found at the level of 10 % RHA. When RHA was used as addition, the optimum 28 Day average compressive strength of block was found as 4.937 N/mm2. When RHA was used as partial replacement for cement, 28 Day average compressive strength of block was found as 3.467 N/mm2. Thermal performances of the RHA lime based blocks were also investigated. It was found that thermal conductivity of RHA lime based block was lower compared with that of the conventional block. The RHA lime based blocks showed better structural and thermal performances. Increased use of RHA will reduce the unit cost of masonry block while improving sustainability.

RETRACTED ARTICLE: Predicting the effects of nanoparticles on early age compressive strength of ash-based geopolymers by artificial neural networks

In the present work, compressive strength of ash-based geopolymers with different mixtures of rice husk ash, fly ash, nano alumina, and nano silica has been predicted by artificial neural networks. The neural network models were constructed by 12 input parameters including the water curing time, the rice husk ash content, the fly ash content, the water glass content, NaOH content, the water content, the aggregate content, SiO2 nanoparticles content, Al2O3 nanoparticles content, oven curing temperature, oven curing time, and test trial number. The value for the output layer was the compressive strength. According to the input parameters in feed-forward back-propagation algorithm, the constructed networks were trained, validated, and tested. The results indicate that artificial neural networks model is a powerful tool for predicting the compressive strength of the geopolymers in the considered range.

PREDICTION OF STRENGTH AND SLUMP OF RICE HUSK ASH INCORPORATED HIGH-PERFORMANCE CONCRETE

This paper describes the development of statistical models to predict strength and slump of rice husk ash (RHA) incorporated high-performance concrete (HPC). Sixty samples of RHA incorporated HPC mixes having compressive strength range of 42–92 MPa and slump range of 170–245 mm were prepared and tested in the laboratory. These experimental data of sixty RHA incorporated HPC mixes were used to develop two models. Six variables namely water-to-binder ratio, cement content, RHA content, fine aggregate content, coarse aggregate content and superplasticizer content were selected to develop the models and ultimately to predict strength and slump of RHA incorporated HPC. The models were developed by regression analysis. Additional five HPC mixes were prepared with the same ingredients and tested under the same testing conditions to verify the ability of the proposed models to predict the responses. The results of the prediction of the models showed good agreement with the experimental data. Thus the developed models can be used to predict slump and 28-day compressive strength of RHA incorporated HPC. The research demonstrated that strength and slump of HPC could be successfully modeled using statistical analysis.

RETRACTED: Prediction of the effects of nanoparticles on early-age compressive strength of ash-based geopolymers by fuzzy logic

In the present work, compressive strength of ash-based geopolymers with different mixtures of % rice husk ash, fly ash, nano alumina and nano silica has been predicted by fuzzy logic. The alkali activating was done by a mixture of sodium hydroxide and sodium silicate solution. It was found that oven curing temperature and sodium hydroxide concentration together with SiO2 nanoparticles has the main effects on compressive strength of the specimens. The fuzzy logic model was constructed by 12 input parameters including the water curing time, the rice husk ash content, the fly ash content, the water glass content, sodium hydroxide content, the water content, the aggregate content, SiO2 nanoparticles content, Al2O3 nanoparticles content, oven curing temperature, oven curing time and test trial number. The value for the output layer was the compressive strength. According to the input parameters in fuzzy model, the input data were trained, validated and tested. The results indicate that fuzzy model is a powerful tool for predicting the effect of nanoparticles on compressive strength of the geopolymers in the considered range.

Properties of freshly mixed self-consolidating concretes incorporating rice husk ash as a supplementary cementing material

This paper presents the key properties of freshly mixed self-consolidating concrete (SCC) incorporating rice husk ash (RHA). Air-entrained SCC mixtures were produced based on the water/binder (W/B) ratios of 0.30–0.40. RHA was used substituting 0–30% of cement by weight. The fresh properties investigated were filling ability, passing ability, segregation resistance, air content, and unit weight. The effects of RHA and W/B ratio on these properties were observed. Test results revealed that the fresh properties were significantly influenced by the W/B ratio and RHA content of concrete. RHA also affected air entrainment and decreased the unit weight of concrete.

Prediction of Compressive Strength of Self compacting Concrete with Flyash and Rice Husk Ash using Adaptive Neuro-fuzzy Inference System

Self-compacting concrete is an innovative concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction even in congested reinforcement without segregation and bleeding. In the present study self compacting concrete mixes were developed using blend of fly ash and rice husk ash. Fresh properties of theses mixes were tested by using standards recommended by EFNARC (European Federation for Specialist Construction Chemicals and Concrete system). Compressive strength at 28 days was obtained for these mixes. This paper presents development of Adaptive Neuro-fuzzy Inference System (ANFIS) model for predicting compressive strength of self compacting concrete using fly ash and rice husk ash. The input parameters used for model are cement, fly ash, rice husk ash and water content. Output parameter is compressive strength at 28 days. The results show that the implemented model is good at predicting compressive strength.

Rice Husk Ash Stabilization of Reclaimed Asphalt Pavement

Abstract The use of a reclaimed asphalt pavement (RAP) and rice husk ash (RHA) mixture in the construction of pavements has benefits in not only reducing the amount of waste materials requiring disposal but can also provide construction materials with significant savings over new materials. The paper presents results of the laboratory evaluation of the characteristics of RAP stabilized with sawdust ash (RHA) with a view to determine its suitability for use as a subbase and base material in flexible pavements. The RAP-RHA mixtures were subjected to British Standard light, BSL (standard Proctor) compactive effort to determine the compaction characteristics and California bearing ratio (CBR). Test results show that the properties of RAP improved when treated with RHA. The particle grading improved from 99.8 % coarse aggregate and 0.2 % fines, with an AASHTO classification of A-1-a for 100 % RAP to 92.5–99.5 % coarse aggregate and 0.5–7.5 % fines, with an AASHTO classification that ranges from A-1-a (granular materials) to A-3 (nonplastic fine sand) for the various RAP-RHA mix proportions to A- 4 (silty materials) for 100 % RHA. Generally, maximum dry density (MDD) decreased and optimum moisture content (OMC) increased with higher RHA content in the mixes. The CBR values decreased with higher RHA content. However, the values increased from 35 (unsoaked) and 23 % (soaked for 24 h) for 100 % RAP to peak values of 41 (unsoaked) and 34 % (soaked for 24 h) for a 70 %RAP/30 %RHA mix that can be used as a subbase material in flexible pavements.

Desiccation Induced Shrinkage of Compacted Tropical Clay Treated with Rice Husk Ash

Desiccation studies are an integral part of material selection for waste containment systems. Laboratory studies on compacted tropical clay (with illite as the dominant clay mineral sourced from an excavation site) treated with up to 16% rice husk ash (RHA); an agro-industrial waste to evaluate its desiccation induced shrinkage and hence its suitability as a cover material in waste containment systems were carried out. Soil-RHA mixtures were compacted using three compactive efforts at -2, 0, 2 and 4% of optimum moisture content (OMC). Compacted samples, extruded from the compaction mould were allowed to air dry in the laboratory for a 30 day period after which they were subjected to two cycles of wetting and drying. Results show that changes in mass and volumetric shrinkage strain (VSS) were large within the first five days of drying and were affected by the compactive effort. VSS increased with higher moulding water content, water content relative to optimum and RHA treatments. VSS were affected by the compactive effort. Acceptable compaction planes were obtained for up to 12% RHA treatment. After two cycles of wetting and drying, it was observed that the rate of capillary rise within the compacted soil increased with lower compactive effort and higher rice husk ash treatment. Lower amount of cracking was observed in soil specimen with higher rice husk ash treatment and higher cracking in soils with lower rice husk ash content. Increased compactive effort reduced the effect of swelling during wetting; showing the suitability of the material as a cover in municipal waste containment facility and beneficial reuse of this agro waste product.

Hydraulic Conductivity of Compacted Tropical Clay Treated with Rice Husk Ash

Laboratory study on compacted tropical clay treated with up to 16% rice husk ash (RHA), an agro-industrial waste; to evaluate its hydraulic properties and hence its suitability in waste containment systems was carried out. Soil-RHA mixtures were compacted using standard Proctor, West African Standard and modified Proctor efforts at-2, 0, 2 and 4% of optimum moisture content (OMC). Compacted samples were permeated and the hydraulic behaviour of the material was examined considering the effects of moulding water content, water content relative to optimum, dry density and RHA contents. Results showed decreasing hydraulic conductivity with increasing moulding water content and compactive efforts; it also varied greatly between the dry and wet side of optimum decreasing towards the wet side. Hydraulic conductivity generally decreased with increased dry density for all effort. Hydraulic conductivity increased with rice husk ash treatment at the OMC; but were within recommended values of 1 x 10-7 cm/s for up to 8% rice husk ash treatment irrespective of the compactive effort used. This shows the suitability of the material as a hydraulic barrier in waste containment systems for up to 8% rice husk ash treatment and beneficial reuse of this agro-industrial waste product.

AIR CONTENT OF SELF-CONSOLIDATING CONCRETE AND ITS MORTAR PHASE INCLUDING RICE HUSK ASH / ORO KIEKIS SAVITANKIAME BETONE IR JO SKIEDINIO DALYJE SU RYŽIŲ LUKŠTŲ PELENAIS

This paper presents the air content results of self-consolidating concrete (SCC) and its mortar phase including rice husk ash (RHA) as a supplementary cementing material. Moreover, this paper demonstrates a simple technique to determine the dosage of air-entraining admixture (AEA) required for the target air content in SCC. Different SCC mixtures were designed based on the water/binder (W/B) ratios of 0.30–0.50 and design air content of 4–8%. RHA was incorporated in the concretes substituting 0–30% of cement by weight. The mortars were formulated from the mixture proportions of the corresponding parent concretes and tested to determine the air content at various AEA dosages. The effects of W/B ratio and RHA content on the air content of both mortar and concrete were observed. The effect of mortar volume on the air content of concrete was also noticed. Besides, the AEA dosages required for the target air contents of concrete were estimated based on the equivalent mortar air contents. Later the air-entrained SCC mixtures were produced using AEA and tested for the air content. Test results exhibit that the air contents of both mortar and concrete were significantly influenced by the W/B ratio and RHA content. The concrete air content was also greatly influenced by its mortar volume. The AEA dosage increased with lower W/B ratio, higher RHA content, and greater mortar volume for the target air contents. In addition, the actual AEA dosages were consistent with the estimated AEA dosages of the concretes. An excellent correlation was observed between the actual and estimated AEA dosages. The strong correlation suggests that the AEA dosage needed for a target air content in concrete can be determined based on the equivalent air content of its mortar phase. Santrauka Straipsnyje pateikiami oro kiekio nustatymo savitankiame betone (SCC) ir jo skiedinio dalyje su ryžių lukštų pelenais (RHA), naudojamais kaip papildoma cementavimo medžiaga, rezultatai. Be to, pateikiamas paprastas būdas parinkti orą įsiurbiančio priedo (AEA) dozę, siekiant gauti reikalingą oro kiekį SCC. Suprojektuoti skirtingi SCC mišiniai su skirtingu vandens ir rišiklio (W/B) 0,30–0,50 santykiu ir numatytu 4–8 proc. oro kiekiu, RHA buvo dedamas į betoną pakeičiant 0–30 proc. cemento pagal masę. Skiediniai buvo formuojami pagal jiems artimo betono sudėtis ir oro kiekis juose bandomas su skirtingomis AEA dozėmis. Nustatyta W/B santykio ir RHA kiekio įtaka oro kiekiui tiek skiedinyje, tiek betone bei skiedinio tūrio įtaka oro kiekiui betone. Be to, AEA dozės, reikalingos numatytam oro kiekiui betone pasiekti, nustatytos pagal ekvivalentinį oro kiekį skiedinyje. Vėliau SCC mišiniai su orą įsiurbiančiu priedu buvo pagaminti naudojant AEA ir išbandytas juose esantis oro kiekis. Tyrimų rezultatai rodo, kad tiek skiedinį, tiek betono oro kiekį labai veikia W/B santykis ir RHA kiekis. Oro kiekį betone taip pat smarkiai veikia skiedinio tūris. Mažėjant W/B santykiui, didėjant RHA kiekiui ir skiedinio tūriui AEA dozė turi būti didinama norimam oro kiekiui pasiekti. Taip pat faktinės AEA dozės atitiko suskaičiuotas betonų AEA dozes. Tarp faktinių ir suskaičiuotų AEA dozių gauta labai gera koreliacija. Ji rodo, kad AEA dozę, reikalingą numatytam oro kiekiui betone pasiekti, galima skaičiuoti pagal ekvivalentinį oro kiekį šio betono skiedinio dalyje.

Properties of EPS RHA lightweight concrete bricks under different curing conditions

The depletion of non-renewable resources has become an alarming issue nowadays. Many environmentalists and researchers have been investigating the use of waste materials as a renewable resource for use especially as raw materials in construction. This paper reports on the potential use of waste rice husk ash (RHA) and expanded polystyrene (EPS) beads in producing lightweight concrete bricks. The RHA was used as a cementitious material since it is a lightweight reactive pozzolanic material. RHA was used as partial cement replacement, while the EPS was used as partial aggregate replacement in the mixes. Bricks of 215 mm × 102.5 mm × 65 mm in size were prepared in this study. The engineering properties of the bricks were investigated. Among the properties studied were hardened concrete density, compressive strength and water absorption of the EPS RHA concrete bricks. Scanning electron microscopy (SEM) analysis was also performed on the brick samples. Four types of curing conditions were employed in this study. These include full water curing, air dry curing, 3-day curing and 7-day curing. It was found that the properties of the bricks are mainly influenced by the content of EPS and RHA in the mix and also the curing condition used.

A study on the engineering properties of sandcrete blocks produced with rice husk ash blended cement

Sandcrete blocks have been in used in many nations of the world including Nigeria, playing a major role in the building industry. The material constituents, their mix, presence of admixtures and the manufacturing process are important factors that determine the properties of sandcrete blocks. This paper investigates the effects of a partial replacement of cement with rice husk ash (RHA) on some engineering properties of hollow sandcrete blocks with 1:6 cement-sand mix ratios. Single block size 225 x 225 x 450 mm, is produced with a vibrating machine. Results show that the addition of RHA produces blocks of lower density. Particularly, the density of the blocks decreases as the RHA content increases. The compressive strength of the block is also not enhanced. Results also reveal that the thermal and hygrothermal properties of the blocks are significantly affected. Key words: Sandcrete blocks, rice husk ash, compressive strength, hygrothermal properties, thermal properties.