scholarly journals 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

2011 ◽  
Vol 17 (3) ◽  
pp. 319-329 ◽  
Author(s):  
Md. Safiuddin ◽  
Jeffrey S. West ◽  
Khaled A. Soudki
Keyword(s):  
Rice Husk ◽  
Strong Correlation ◽  
Simple Technique ◽  
Rice Husk Ash ◽  
Test Results ◽  
Excellent Correlation ◽  
Self Consolidating Concrete ◽  
Air Content ◽  
Cementing Material

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.

Flowing ability of self-consolidating concrete and its binder paste and mortar components incorporating rice husk ash

2010 ◽  
Vol 37 (3) ◽  
pp. 401-412 ◽  
Author(s):  
Md. Safiuddin ◽  
J. S. West ◽  
K. A. Soudki
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Flow Time ◽  
Test Results ◽  
Self Consolidating Concrete ◽  
Concrete Mixtures ◽  
Slump Flow ◽  
High Range

This paper presents the flowing abilities of various self-consolidating concretes (SCCs) and their binder paste and mortar components. The binder pastes and mortars were formulated from the concrete mixtures and tested for flowing ability with respect to flow time and flow spread, respectively, at various dosages of high-range water reducing admixture (HRWRA). The concrete mixtures were prepared with different water (W) to binder (B) ratios and rice husk ash (RHA) contents. The flowing ability of the concretes was measured with regard to slump flow, orimet flow time and flow spread, and inverted slump cone flow time and flow spread. The test results reveal that the W:B ratio, RHA content, and HRWRA dosage significantly influenced the flowing abilities of the binder pastes, mortars, and concretes. In addition, the flowing ability of the SCCs was well correlated with the flowing abilities of their binder paste and mortar components, except for the mortars including RHA.

scholarly journals Effect of temperature on early-age properties of self-consolidating concrete equivalent mortar

2020 ◽  
Vol 5 ◽  
pp. 114-122
Author(s):  
Nima Farzadnia ◽  
Jing Pan ◽  
Kamal Khayat ◽  
Eric Wirquin
Keyword(s):  
Heat Flux ◽  
Compressive Strength ◽  
Effect Of Temperature ◽  
Early Age ◽  
Test Results ◽  
Hydration Kinetics ◽  
Self Consolidating Concrete ◽  
Air Content ◽  
Cementing Material ◽  
Material Temperature

In this study, the effect of material temperature during casting on fresh properties, hydration kinetics, and early-age compressive strength of self-consolidating concrete (SCC) was evaluated. Concrete equivalent mortars (CEMs) based on SCC mixture designs with water-to-binder ratios of 0.41 and 0.45 were investigated. The SCC mixtures are targeted for infrastructure and building construction and precast applications. The CEMs were prepared at temperatures ranging from 8 to 36°C.  Superplasticizer (SP) and air-entraining agent (AEA) demand were evaluated for the CEM mixtures made with different supplementary cementing material (SCM) and limestone filler types. Test results showed that the ambient temperature can significantly affect the SP and AEA demand, hydration kinetics, and compressive strength after 1 d of age. According to the ultraviolet–visible spectrophotometry (UV/Vis) test, the absorption rate of polycarboxylate-based SP decreased with temperature. In contrast, the sensitivity of polynaphthalene sulfonate-based SP to temperature was minimal. Relationships between the variations of different admixture contents, heat flux, and compressive strength with temperature were developed. For a constant slump flow and air content, the demand of the SP and AEA, heat flux, and 1-d compressive strength of CEMs increased linearly with material temperature.

Physical Properties of Cement Mortar Containing Waste Ash

2015 ◽  
Vol 804 ◽  
pp. 129-132
Author(s):  
Sumrerng Rukzon ◽  
Prinya Chindaprasirt
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cement Mortar ◽  
Ash Content ◽  
Water Requirement ◽  
Test Results ◽  
Pozzolanic Material ◽  
Materials Used

This research studies the potential for using waste ash from industrial and agricultural by-products as a pozzolanic material. Classified fly ash (FA) and ground rice husk ash (RA) were the materials used. Water requirement, compressive strength and porosity of cement mortar were investigated. Test results indicated that FA and RA (waste ash) have a high potential to be used as a good pozzolanic material. The water requirement of mortar mix decreases with the increases in fly ash content. For ground rice husk ash (RA), the water requirement of mortar mix increases with the increases in rice husk ash content. In addition, the reduction in porosity was associated with the increase in compressive strength.

Properties of Unfired Building Bricks Prepared from Fly Ash and Residual Rice Husk Ash

2015 ◽  
Vol 754-755 ◽  
pp. 468-472 ◽  
Author(s):  
Chao Lung Hwang ◽  
Trong Phuoc Huynh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Fine Aggregate ◽  
Test Results ◽  
Design Algorithm ◽  
Potential Applications ◽  
Hardened Properties

This work investigates the possibility of using fly ash (FA) and Vietnam residual rice husk ash (RHA) in producing unfired building bricks with applying densified mixture design algorithm (DMDA) method. In this research, little amount of cement was added into the mixtures as binder substitution. Unground rice husk ash (URHA), an agricultural by-product, was used as partial fine aggregate replacement (10% and 30%) in the mixtures. The solid bricks of 220×105×60 mm in size were prepared in this study. The hardened properties of the bricks were investigated including compressive strength, flexural strength and water absorption according to corresponding Vietnamese standards. Forming pressure of 35 MPa was applied to form the solid bricks in the mold. The test results show that all brick specimens obtained good mechanical properties, which were well conformed to Vietnamese standard. Compressive strength and flexural strength of the bricks were respectively in range of 13.81–22.06 MPa and 2.25–3.47 MPa. It was definitely proved many potential applications of FA and RHA in the production of unfired building bricks.

scholarly journals Research progress of rice husk ash in solidified soil

2021 ◽  
Vol 293 ◽  
pp. 02018
Author(s):  
HAO Tong ◽  
LIU Qian ◽  
Fa-Guang Leng ◽  
Tian-Long Qiao
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Cementitious Materials ◽  
Mineral Admixture ◽  
Added Value ◽  
Research Progress ◽  
Utilization Rate ◽  
Application Range ◽  
High Silicon ◽  
Cementing Material

Rice husk ash is a kind of volcanic ash material with high silicon. This also provides a feasibility for rice husk ash as cement-based auxiliary cementing material. China is rich in rice husk resources, and the rice husk ash is stacked. Using rice husk ash (RHA) instead of traditional cementitious materials can effectively solve the environmental pollution caused by the accumulation of rice husk ash. Domestic and international scholar have added rice husk ash as mineral admixture to concrete, but the utilization rate is very low. In order to increase the added value of rice husk ash, the high silicon property of rice husk ash was used to solidify soil. The application range of solidified soil is wide, the requirements for materials are not high, and the functions are different, which can realize the extensive use of rice husk ash. This paper summarizes the literature on comprehensive utilization of rice husk ash at home and abroad, systematically expounds the physicochemical properties and production process of rice husk ash, introduces the application of rice husk ash in solidified soil, and points out the unsolved problems in this field, which provides a direction for the further development.

Sign in / Sign up

Export Citation Format

Share Document