scholarly journals Influence of Rice Husk Ash Density on the Workability and Strength of Structural Concrete

2017 ◽  
Vol 2 (3) ◽  
pp. 36 ◽  
Author(s):  
John Kamau ◽  
Ash Ahmed ◽  
Fraser Hyndman ◽  
Paul Hirst ◽  
Joseph Kangwa
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Water Demand ◽  
Rice Husk Ash ◽  
Concrete Strength ◽  
High Water ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hardened Concrete ◽  
Structural Applications

Supplementary cementitious materials (SCMs) have been known to improve the properties of fresh and hardened concrete, and at the same time enhance the sustainability of concrete. Rice husk Ash (RHA), is one such material, but has neither been widely studied nor applied in practice. This work investigated the effect of the density of RHA on the workability and compressive strength of fresh and hardened RHA-replaced concrete respectively. Cement was replaced with RHA in concrete by weight (RHA-W) and by volume (RHA-V) at steps of 0%, 5%, 7.5%, 10%, 15%, 20%, 25% and 30%. The 0% replacement was used as the reference point from which performances were measured. Results showed that unlike the characteristic of other established pozzolans, RHA significantly reduced the workability of wet concrete and the rate of compressive strength gain over curing time due to a high water demand that is caused by the increased volume of replaced concrete, which results from its low density. Workability reduced with increased replacement for both RHA-W and RHA-V. Replacements of above 15% were not possible for the RHA-W due to the high water demand. However, replacements of up to 30% were achieved for the RHA-V. RHA-W specimens achieved lower compressive strengths and were observed to gain strength at a lower rate over the 28 to 91-days period of curing compared to RHA-V specimens. This behavior was attributed to the shortage of water that is necessary for the hydration of cement and subsequent pozzolanic reaction, which is the basis of the contribution that is made to the strength and performance of concrete by SCMs. However, the compressive strengths achieved were above the study’s target concrete strength of class C32/40 at 91 days, which is among those classes that are listed as being durable and suitable for structural applications. A conclusion that RHA should supplement cements by volumetric replacement rather than simple substitution by weight was drawn.

scholarly journals Compressive Strength of Concrete using Fly Ash and Rice Husk Ash: A Review

2020 ◽  
Vol 6 (7) ◽  
pp. 1400-1410
Author(s):  
Joel Sam
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Compressive Strength Of Concrete ◽  
Minor Compounds

Decreasing our over-reliance on cement as an ingredient in the making of concrete due to its contribution to the CO2 emissions has led to numerous researches been conducted to find suitable replacement for cement in concrete mixes.  Materials like fly ash, ground granulated blast furnace slag, silica fume, rice husk ash and metakaolin among others have been identified as materials that can at the very least be used as a replacement for cement in concrete mix. These materials are referred to as supplementary cementitious materials (SCMs). This paper reviewed the work that has been done on the use of fly ash and rice husk ash as partial replacements for concrete, its chemical composition and its effect on the compressive strength of concrete. Charts, tables and figures were employed as tools to study the various chemical compounds of fly ash and rice husk ash. It was seen that depending on how the coal or rice husk was initially processed the percentage of some of the minor compounds like Sodium oxide (Na2O), Titanium oxide (TiO2) and Phosphorus pentoxide (P2O5) were sometimes very low or not recorded as part of the final product.  The data on the compressive strength of concrete after fly ash and rice husk ash had been added in percentage increments of 0%, 10%, 20%, 30%, 40%, 50% and 0%, 5%, 7.5%, 10%, 12.5%, 15% respectively analysed over a minimum period of 7 days and a maximum period of 28 days found out that the optimal percentage partial replacement of fly ash and rice husk ash for a strong compressive concrete strength is 30% of fly ash and 7.5% of rice husk ash.

scholarly journals Use of Rice Husk Ash (RHA) as a Supplementary Cementitious Material in Producing Normal Concrete

2019 ◽  
Vol 271 ◽  
pp. 07007
Author(s):  
Kazi islam ◽  
Zahid Hossain
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Material ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hardened Concrete ◽  
Type I ◽  
Continuous Increase ◽  
Material Sources ◽  
By Products

With the continuous increase of scarcity of the natural construction material sources and environmental awareness, utilization of wastes/by-products in the construction industry has become an attractive field of study. Several industrial by-products produced from different manufacturing processes have been considered for various usages in the construction field. This paper briefly describes the potential use of Rice Husk Ash (RHA) as Supplementary Cementitious Materials (SCM). Here, three different grades of RHA (600-RHA, 150-RHA, and 44-RHA) in two different percentages (10 % and 20 %) of replacement of Type I Ordinary Portland Cement (OPC) were investigated. Laboratory tests on the fresh concrete mix as well as the mechanical properties of the hardened concrete were performed. It was observed that coarser RHA-modified concrete (600-RHA and 150-RHA) showed reduced strength properties while finer RHA (44-RHA) exhibited improved concrete properties. Moreover, the incorporation of RHA in concrete was found to be effective in mitigating alkaline expansion.

Rice Husk Ash as a Cement Replacement in High Strength Sustainable Concrete

2020 ◽  
Vol 1007 ◽  
pp. 90-98
Author(s):  
Ash Ahmed ◽  
Fraser Hyndman ◽  
John Kamau ◽  
Heni Fitriani
Keyword(s):  
Mechanical Properties ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Construction Material ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Strength Development ◽  
Coal Waste ◽  
Environmental Implications ◽  
Sustainable Concrete

Cement is the most utilized construction material. The energy-intensive processes that are involved in its production contribute up to 10% of total global CO2 emissions, with potentially adverse environmental implications. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of clinker, and in its place utilising supplementary cementitious materials (SCMs) or pozzolans that require less process heating and emit fewer levels of CO2. Currently, most sustainable concrete uses either GGBS (slag) or PFA (fly ash) to reduce the quantity of cement used in construction and highways applications. GGBS and PFA come from industries (steel and coal waste respectively) which are in decline that should not be relied upon in the long term. This report shows that cement in concrete can also be replaced with rice husk ash (RHA) which actually enhances the mechanical properties. RHA comes from the food production industry and is vital for the growing global population. It is thus a socially responsible objective to use a pozzolan in civil engineering applications that is sourced from an environmentally friendly and sustainable industry. This study investigated the potential of RHA to be used as a SCM by evaluating mechanical properties. Experiments were carried out by supplementing cement in concrete mixes with RHA at up to 10% replacement by mass. Results were compared with a control specimen (100% cement), with a water/binder (w/b) ratio of 0.4 and C32/40 design mix using CEM I. The results show excellent early age strengths with all RHA mixes surpassing 40 MPa strength within 7 days which is contrary to general trends in SCM concrete where strength development is slow in the initial stages in comparsion to 100% cement concrete. All RHA specimens exhibited impressive flexural and tensile strengths.

Utilization of kimberlite tailings as aggregates in concrete – strength and selected durability properties

MRS Advances ◽  
2020 ◽  
Vol 5 (25) ◽  
pp. 1259-1266
Author(s):  
Mike Otieno ◽  
Esina Ndoro
Keyword(s):  
Compressive Strength ◽  
Water Demand ◽  
Concrete Strength ◽  
High Water ◽  
Negative Effects ◽  
Coarse Aggregates ◽  
Durability Properties ◽  
Mix Proportioning ◽  
Water Sorptivity ◽  
Strength And Durability

AbstractThe feasibility of using kimberlite tailings as aggregates in concrete was assessed. Compressive strength and selected durability tests were carried out on concretes made using various replacement levels (0, 40, 60 and 100%) fine and/or coarse blended crushed andesite and kimberlite tailings as aggregates. A w/b ratio of 0.50 and a CEM I 52.5R were used. The results show that the kimberlite tailings as aggregates have a relatively high water demand which was manifested as a reduction in workability of the fresh concretes with kimberlite tailings as a proportion of either fine and/or coarse aggregates. The results also showed that the use of the kimberlite tailings as a proportion of either fine or coarse aggregates in concrete resulted in a decrease in both compressive strength and durability properties viz water sorptivity and oxygen permeability. This was partly attributed to the low workability of the concretes which is known to limit the degree of compaction of fresh concrete. It is envisaged that careful concrete mix proportioning including the use of admixtures and pre-wetting of the aggregates can be used to offset the negative effects of high water demand of the kimberlite aggregates.

Assessment of Rice Husk Ash (RHA) and Calcium Chloride (CaCl2) on Compressive Strength of Concrete Grade 20

2018 ◽  
Vol 40 ◽  
pp. 22-29
Author(s):  
Joseph A. Ige ◽  
Mukaila A. Anifowose ◽  
Samson O. Odeyemi ◽  
Suleiman A. Adebara ◽  
Mufutau O. Oyeleke
Keyword(s):  
Compressive Strength ◽  
Calcium Chloride ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Conventional Concrete ◽  
Compressive Strength Test ◽  
Compressive Strength Of Concrete ◽  
Strength Result

This research assessed the effect of Nigerian rice husk ash (RHA) and calcium chloride (CaCl2) as partial replacement of cement in concrete grade 20. Rice husk ash (RHA) is obtained by combustion of rice husk in a controlled temperature. The replacement of OPC with rice husk ash (RHA) were 0%, 5%, 10%, 15% and 20%. 1% of Calcium Chloride was blended with OPC/RHA in all the test specimens except from control mix. Concrete cubes of sizes 150mm x 150mm x 150mm were cast and cured in water for 7, 14 and 28 days respectively. Slump test was conducted on fresh concrete while density test and compressive strength test were conducted on hardened concrete. The slump results revealed that the concrete becomes less workable (stiff) as percentage increases. The compressive strength result at 28 days revealed that 5%RHA/1%CaCl2 have the highest strength of 26.82N/mm2 while 20%RHA/1%CaCl2 have the lowest strength (21.48N/mm2). Integration of 5%RHA/1%CaCl2 and 10%RHA/1%CaCl2 as cement replacement will produce a concrete of higher compressive strength compared to conventional concrete in grade 20 concrete.

scholarly journals Measurement of Pozzolanic Activity Index of Scoria, Pumice, and Rice Husk Ash as Potential Supplementary Cementitious Materials for Portland Cement

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Hieronimi A. Mboya ◽  
Cecil K. King’ondu ◽  
Karoli N. Njau ◽  
Alex L. Mrema
Keyword(s):  
Portland Cement ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Activity Index ◽  
Cementitious Materials ◽  
Pozzolanic Activity ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Setting Times

This work investigated the properties of scoria and pumice as supplementary cementitious materials (SCMs) for Portland cement and compared to those of rice husk ash (RHA). X-ray fluorescence, X-ray diffraction, and pozzolanic activity index (PAI) tests confirmed the suitability of these two materials as potential SCMs. Scoria and RHA samples achieved over 75% PAI at 7 days whereas pumice did this after 28 days. Initial and final mean setting times observed for the composite cement blended with these materials were 166 and 285 min, respectively. These setting times are longer than that of ordinary Portland cement but shorter compared to that of common Portland pozzolana cement. The ultimate mean compressive strengths achieved at 28 days of curing were 42.5, 44.8, and 43.0 MPa for scoria, pumice, and RHA, respectively, signifying that these materials are good SCMs. Higher fineness yielded higher ultimate mean strength. For instance, a scoria sample with a fineness of 575 m2/kg achieved the strength of 52.2 MPa after 28 days.

Investigation on High Volume Steel Slag - Rice Husk Ash Composite Binder Properties

2014 ◽  
Vol 599 ◽  
pp. 310-314
Author(s):  
Yan Hua Wang ◽  
Jun Cai ◽  
Pin Pin Ding ◽  
Ya Jun Wang
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Frost Resistance ◽  
Rice Husk Ash ◽  
Steel Slag ◽  
Drying Shrinkage ◽  
High Volume ◽  
Cementitious Materials ◽  
The Novel ◽  
Composite Binder

This paper discussed the possibilities of the processed steel slag and rice husk ash in building mortar replace cement. Experimental results show that after suitable mix designs cube compressive strength of composite binders using can meet the building mortar standard. The novel composite cementitious materials need larger water absorption, but their frost resistance, drying shrinkage, sulfate resistance relate to the pure cement varying degrees upgrade.

scholarly journals Influence of aggregate and supplementary cementitious materials on the properties of hydrated lime (CL90s) mortars

2016 ◽  
Vol 66 (324) ◽  
pp. 104 ◽  
Author(s):  
S. Pavía ◽  
M. Aly
Keyword(s):  
Water Demand ◽  
Hydrated Lime ◽  
High Water ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Supplementary Cementitious Materials ◽  
Silica Sand ◽  
Property Variation ◽  
Hygric Properties ◽  
Increased Strength

Hydrated lime is a historic material currently used in conservation. It hardens slowly by carbonation slowing construction however, supplementary cementitious materials accelerate hardening enhancing strength. Hydrated-lime mortars with rice husk ash–RHA-; ground granulated blastfurnace slag–GGBS- and increasing amounts of two aggregates were studied. Increasing aggregate lowered strength as interfacial zones proliferate; it lowered hygric properties and raised water demand. Aggregate content/composition didn’t affect the high water retention. For the higher aggregate contents (90 days), limestone mortars are c.20% stronger than silica mortars while the (1:1) silica sand mortars are 56% stronger in flexion. Additions increased strength with little impact on hygric properties. GGBS increased strength c.six times. RHA increased strength with little impact on hygric properties due to its great specific surface and high water-demand increasing porosity. GGBS and RHA properties ruling hydrate production and the kinetics of the pozzolanic reaction are considered partially responsible for the mortar property variation.

scholarly journals Prediction of Compressive Strengths for Rice Husks Ash incorporated concrete, Using Neural Network and Reviews

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Cornelius Ngunjiri Ngandu
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Concrete Strength ◽  
Cementitious Material ◽  
Machine Learning Techniques ◽  
Percentage Error ◽  
Green Concrete ◽  
Original Dataset ◽  
Wide Range

Modelling of concrete that incorporates agricultural wastes such as rice husk ash (RHA) could potentially enhance utilization of green concrete and application of sustainable construction materials. This paper evaluations compressive strength prediction for rice husk ash (RHA) cementitious material incorporated concrete using artificial neural networks (ANNs) one of the various prediction methods.  The research is based on various previous experimental studies.Literature reviews of 72 datasets for RHA incorporated concrete from 15 previous researches, were used and subjected to ANNs models, having learning rate of 0.06 with tanh activation functions. Four(4) input variables were considered, namely:- superplasticizer or water reducers variation from control (%), water to binder ratio, percentage of RHA and control compressive strengths. Output variable was compressive strength of RHA cementitious material incorporated concrete. The ANN with 15 neurons in the hidden layer was selected and indicated overall values of 5.10MPa, 0.99, 3.81MPa and 9.73% for the root mean square error (RMSE), absolute factor of variance (R2), mean absolute error (MAE) and mean absolute percentage error (MAPE) respectively and for individual training, validation/checking and testing datasets, the RMSE, R2, MAE and MAPE ranging between 3.98MPa-6.56MPa, 0.98-0.99, 3.44MPa-4.94MPa and 9.19%-12.41% respectively. Generally, both predicted and original dataset, indicated higher and lower strength values for 5-10% and 15-30% RHA incorporated cementitious material concrete respectively compared to the control strengths.Considering that the study utilized data from different sources and with a wide range of concrete strengths the selected ANN showed relatively good performance. The study provides an indicator that machine learning techniques could accurately predict green concrete strength. Based on model performance the percentage RHA cementitious materials in concrete and the other 3 input variable had a significant impact on concrete strengths. Future research should be conducted to predict green concrete focused on particular concrete class.

scholarly journals A Study on the Strength Aspects of Concrete with Metakaolin, GGBFS and Rice Husk Ash as Partial Replacement of OPC

2021 ◽  
Vol 889 (1) ◽  
pp. 012072
Author(s):  
Amit Sharma ◽  
Sanjeev Gupta
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Research Work ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Engineering Properties ◽  
Partial Replacement ◽  
Test Results ◽  
Conventional Concrete ◽  
The Impact

Abstract The impact of the OPC on the environment is important as its production generates a large amount of CO2. In order to reduce the use of pure raw materials as resources, the use of industrial waste or secondary materials in construction sites for the production of cement and concrete has been encouraged. The volume of wastes generated worldwide has increased over the years due to the population, social and economic performance and social development. One of the most attractive options for waste management is to minimize waste and reuse the possibility of recycling. The cost of cement used in concrete works is increasing and unsatisfactory, but the demand for this material and other housing needs is rising, so it is important to find alternatives that can be used alone or in a partial replacement. In this research work several auxiliary cementitious ingredients such as metakaoline, GGBFS and Rice Husk Ash (RHA) were used to improve the strength properties of the conservative concrete. Metakaolin and GGBFS was used at a fixed percentage of 10 percent as fractional substitution of the OPC-43 grade cement, while the RHA was used at different percent ranging from 0 to 25 percent at an increment of 5 percent in each case as fractional substitution of the OPC-43 grade cement. Numerous examinations were executed so as to envisage the effect of these materials over the strength and engineering properties of the concrete. The test results conclude that the usage of the metakaolin, GGBFS and the RHA in combined form increased the strength and engineering properties of the conventional concrete up to a great extent. From the obtained test results it can be further concluded that the particle size of the supplementary cementitious materials plays a significant role in enhancing the internal micro-structure of the concrete and which further leads to the higher strength of the concrete. Also the main reason behind the advanced strength was the presence of the metakaolin and GGBFS in the concrete, whose chemical properties densifies the concrete and made the concrete more stable and promotes higher strength. Future work can also be done on the usage of several other supplementary cementitious materials at different other percentages so as to improve concrete properties.

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