scholarly journals Strength and Durability Performance of Alkali-Activated Rice Husk Ash Geopolymer Mortar

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Yun Yong Kim ◽  
Byung-Jae Lee ◽  
Velu Saraswathy ◽  
Seung-Jun Kwon
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Polymerization Reaction ◽  
Strength Development ◽  
Geopolymer Concrete ◽  
Portland Cement Concrete ◽  
Mix Proportion ◽  
Strength And Durability ◽  
Alkali Activated

This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive strengths of 31 N/mm2and 45 N/mm2, respectively for the 10 M alkali-activated geopolymer mortar after 7 and 28 days of casting when cured for 24 hours at 60°C. Results indicated that the increase in curing period and concentration of alkali activator increased the compressive strength. Durability studies were carried out in acid and sulfate media such as H2SO4, HCl, Na2SO4, and MgSO4environments and found that geopolymer concrete showed very less weight loss when compared to steam-cured mortar specimens. In addition, fluorescent optical microscopy and X-ray diffraction (XRD) studies have shown the formation of new peaks and enhanced the polymerization reaction which is responsible for strength development and hence RHA has great potential as a substitute for ordinary Portland cement concrete.

scholarly journals Effect of Incorporation of Rice Husk Ash Instead of Cement on the Performance of Steel Fibers Reinforced Concrete

2021 ◽  
Vol 8 ◽  
Author(s):  
Osama Zaid ◽  
Jawad Ahmad ◽  
Muhammad Shahid Siddique ◽  
Fahid Aslam
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Steel Fibers ◽  
Concrete Compressive Strength ◽  
Brittle Behavior ◽  
Direct Combustion ◽  
Low Performance ◽  
Strength And Durability ◽  
Reference Samples

The production of rice is significant worldwide; the husk produced is generally used as a combustible material for the preparation of paddies, delivering energy through direct combustion as well as by gasifying. Annually, 7.4 million tons of Rice Husk Ash (RHA) is produced and poses an incredible danger to the environment, harming the land and the encompassing zone where it is unloaded. In the transformation of rice husk to ash, the ignition cycle eliminates the natural products, leaving silica-rich remains. These silica-rich remains have proven to have potential to be utilized in concrete as a limited substitution of cement to enhance the concrete compressive strength. Steel fibers’ incorporation increases the concrete tensile strength, balances out concrete samples, and changes their brittle behavior to a more ductile response. In the current study, the influence of various doses of Rice Husk Ash (RHA) used in concrete in the presence and absence of steel fibers and concrete performance has been examined. A total of nine mixes have been designed: one was a control, four were without steel fibers containing only RHA, and the last four mixed RHA with steel fibers from 0.5 to 2%. Tests with 5, 10, 15, and 20% percentages of RHA replacing the concrete have been targeted. Results have been compared with the reference samples and the reasonability of adding Rice Husk Ash to concrete has been studied. From the results, it was noted that about 10% of cement might be replaced with Rice Husk Ash mixed in with steel fibers with almost equal compressive strength. Replacing more than 15% of cement with RHA will produce concrete with a low performance in terms of strength and durability.

scholarly journals Physicochemical Properties of Hydrated Portland Cement Blended with Rice Husk Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Joseph Mwiti Marangu ◽  
Cyprian Muturia M’thiruaine ◽  
Mark Bediako
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Rice Husk ◽  
Elevated Temperatures ◽  
Rice Husk Ash ◽  
Blended Cement ◽  
Strength Development ◽  
Carbonation Depth ◽  
Blended Cements ◽  
Carbonation Resistance

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.

Improved Acid Rain Resistance of High Calcium Fly Ash-sodium Hydroxide Geopolymer Mortar Cured at Ambient Temperature by Incorporating Rice Husk Ash

2021 ◽  
Vol 47 (2) ◽  
pp. 324-331
Author(s):  
Prinya Chindaprasirt ◽  
Kiatsuda Somna
Keyword(s):  
Compressive Strength ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Nitric Acid ◽  
Acid Rain ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Acid Resistance ◽  
Portland Cement Concrete ◽  
High Calcium

Geopolymer is an aluminosilicate material, synthesized from source materials rich in silica and alumina and alkali solution. This product provides similar strength to Portland cement concrete. Geopolymer exhibits a wide variety of properties and characteristics, including high compressive strength, low shrinkage, acid resistance, fire resistance and low thermal conductivity. In term of acid resistance, acid rain is an important consideration due to global warming. Structures deteriorate as a result of persistence contact with acid rain with of pH less than 5. Thus, this research aims to improve acid resistance of fly ash-NaOH geopolymer mortars by incorporating rice husk ash (RHA). Artificial acid rain solution was prepared by mixing nitric acid and sulfuric acid at the ratio of 70:30 v/v. The geopolymer mortars were immersed in 5% nitric acid, 5% sulfuric acid, and 5% synthetic acid rain solutions for 36 weeks. The evaluations of its resistance to acid solution was investigated with surface corrosion, compressive strength, and microstructure. The results showed that the incorporation of RHA improved the acid rain resistance of geopolymer mortar through pore refinement and increase in strength. The mortar with fly ash to RHA ratio of 90:10 provided the highest compressive strength and good resistance to acid rain.

Performance of Mortar Grouts Incorporating Rice Husk Ash and Fly Ash

2019 ◽  
pp. 31-48
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Apparent Volume ◽  
Partial Replacement ◽  
Hardened State ◽  
Strength And Durability ◽  
Penetration Tests

Chapter 3 is based on performance of mortar grouts incorporating rice husk ash (RHA) and fly ash (FA). Detailed experimental work was conducted to investigate the mechanical properties of mortar grout using RHA and FA as partial replacement of cement. This study investigated the compressive strength and durability of mortar grouts in their hardened state. Durability tests such as water absorption, apparent volume of permeable voids, sorptivity, and rapid chloride penetration tests are researched. Detailed results and discussion which focused on mechanical properties as well as durability of hardened state mortar grout are presented. It was confirmed that the inclusion of blended RHA and FA significantly improved the compressive strength of mortar grouts. The durability of mortar grout increased along with a longer curing time. Hence, RHA and FA can partially replace cement in the production of mortar grouts.

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