Development of Classified Fly Ash as a Pozzolanic Material

This research studies the potential for using classified fly ash from Mae Moh power plant in Thailand as a pozzolanic material.This research studies the potential for using classified fly ash from Mae Moh power plant in Thailand as a pozzolanic material. Three different fly ash finenesses viz., coarse Original Fly Ash (OFA), Medium Fly Ash (MFA) and Fine Fly Ash (FFA) were used for the study. Ordinary Portland Cement (OPC) was partially replaced with fly ash at 20 and 40% by weight of binder. The water to binder ratio was kept constant at 0.5 and the flow of mortar was maintained at 110±5% with the aid of superplasticizer (SP). Compressive strength, carbonation depth and porosity test of mortars were determined. FFA has a high potential to be used as a good pozzolanic material. The use of FFA produces mortars with good strength and low porosity. The resistance to carbonation of mortar improves with partial replacement of FFA in comparison with the normal coarse fly ash. The use of FFA results in a strong and dense mortar which is due to better dispersion and filling effect as well as an increase in the pozzolanic reaction

Use of waste ash from various by-product materials in increasing the durability of mortar

This paper presents a study on the strength and corrosion resistance of mortars made with binary blends of ordinary Portland cement (OPC) and ground rice husk ash (RHA) or ground palm oil fuel ash (POA).This paper presents a study on the strength and corrosion resistance of mortars made with binary blends of ordinary Portland cement (OPC) and ground rice husk ash (RHA) or ground palm oil fuel ash (POA). The mortar mixtures were made with Portland cement Type I containing 0-40% RHA and POA. RHA and POA with 1-3% by weight retained on a sieve No.325 were used. The water to binder ratio was kept constant at 0.5 and the flow of mortar was maintained at 110±5% with the aid of superplasticizer (SP). Scanning electron microscopy (SEM) was used for analysis. The compressive strength, chloride penetration and corrosion resistance of the mortar were determined. The results show that strength as well as the resistance of mortar to chloride and corrosion can be improved by blending with RHA and POA. Thus, RHA and POA have a high potential to be used as a good pozzolanic material

Strength and chloride resistance of blended Portland cement mortar containing palm oil fuel ash and fly ash

This paper presented a study on the strength and chloride resistance of mortars made with ternary blends of ordinary Portland cement (OPC), ground palm oil fuel ash (POA), and classified fly ash (FA). The mortar mixtures were made with Portland cement type I containing 0-40wt% FA and POA. FA and POA with 1wt%-3wt% retained on a sieve No.325 were used. The compressive strength and rapid chloride penetration depth of mortars were determined.This paper presented a study on the strength and chloride resistance of mortars made with ternary blends of ordinary Portland cement (OPC), ground palm oil fuel ash (POA), and classified fly ash (FA). The mortar mixtures were made with Portland cement type I containing 0-40wt% FA and POA. FA and POA with 1wt%-3wt% retained on a sieve No.325 were used. The compressive strength and rapid chloride penetration depth of mortars were determined. The results reveal that the use of ternary blended cements produces good strength mortars. The use of the blend of FA and POA also produces high strength mortars and excellent resistance to chloride penetration owing to the synergic effect of FA and POA. A mathematical analysis and two-parameter polynomial model were presented to predict the compressive strength. The mathematical model correlated well with the experimental results. The computer 3-D graphics of strength of the ternary blended mortars were also constructed and could be used to aid the understanding and the proportioning of the blended system

Pore structure changes of blended cement pastes containing fly ash, rice husk ash, and palm oil fuel ash caused by carbonation

In this paper, the effects of carbonation on pore structure of blended pozzolan cement pastes were investigated. Ordinary Portland cement _OPC_ was partially replaced with ground palm oil fuel ash _POA_, ground rice husk ash _RHA_ and classified fine fly ash _FA_. The strength, total porosity, specific surface area, and pore size distribution were tested.In this paper, the effects of carbonation on pore structure of blended pozzolan cement pastes were investigated. Ordinary Portland cement _OPC_ was partially replaced with ground palm oil fuel ash _POA_, ground rice husk ash _RHA_ and classified fine fly ash _FA_. The strength, total porosity, specific surface area, and pore size distribution were tested. In general, incorporation of pozzolans increased the total porosity of blended cement pastes in comparison to that of OPC paste. Carbonation of pastes under 5% CO2 and 50% relative humidity _RH_ for 28 days resulted in filling of the pore voids and possible attack on calcium silicate hydrate _CSH_ depending on the type of pozzolan used. After carbonation, total porosity decreased and specific surface areas of the blended pozzolan cement pastes reduced indicating the infilling of voids. Pore size distributions of POA and RHA pastes were different to those of FA pastes. Large pores of the POA and RHA pastes were increased indicating coarsening of pores owing to possible attack on CSH. It is possible that POA and RHA were highly reactive and hence their uses resulting in severe carbonation compared to use of FA

An Experimental investigation of the carbonation of blended portland cement palm oil fuel ash mortar in an indoor environment

This research, palm oil fuel ash was utilized as a pozzolanic material in blended Portland cement mortar. The mortar was tested on the normal compressive strength and the negative effect of carbonation in indoor environment using the accelerated carbonation test of 5% CO2 in 50% relative humidity. Three palm oil fuel ash fractions of different fineness, viz., coarse original palm oil fuel ash (CPOA), medium palm oil fuel ash (MPOA) and fine palm oil fuel ash (FPOA) were used for the study. Ordinary Portland cement (OPC) was partially replaced by these palm oil fuel ashes at the dosages of 20% and 40% by weight of binder.In this research, palm oil fuel ash was utilized as a pozzolanic material in blended Portland cement mortar. The mortar was tested on the normal compressive strength and the negative effect of carbonation in indoor environment using the accelerated carbonation test of 5% CO2 in 50% relative humidity. Three palm oil fuel ash fractions of different fineness, viz., coarse original palm oil fuel ash (CPOA), medium palm oil fuel ash (MPOA) and fine palm oil fuel ash (FPOA) were used for the study. Ordinary Portland cement (OPC) was partially replaced by these palm oil fuel ashes at the dosages of 20% and 40% by weight of binder. The results showed that the incorporation of the ashes affected the strength and the carbonation depths of mortars. The strengths of mortar slightly decreased with the increases in the dosage of the ash. The fineness of ash, on the other hand, improved the strength and the carbonation of the mortars. The mortars containing FPOA exhibited high strength and relatively low carbonation in comparison to those using coarser MPOA and CPOA. The use of FPOA resulted in a strong and dense mortar owing to the increased packing effect and pozzolanic reaction. It was therefore, demonstrated that the FPOA could be used as a pozzolanic material to replace part of Portland cement for use in the indoor environment

Strength, porosity and corrosion resistance of ternary blend Portland cement, rice husk ash and fly ash mortar

This paper presents a study of the strength, porosity and corrosion resistance of mortars made with ternary blends of ordinary Portland cement (OPC), ground rice husk ash (RHA) and classified fly ash (fine fly ash, FA). Compressive strength, porosity and accelerated corrosion with impressed voltage (ACTIV) were tested.This paper presents a study of the strength, porosity and corrosion resistance of mortars made with ternary blends of ordinary Portland cement (OPC), ground rice husk ash (RHA) and classified fly ash (fine fly ash, FA). Compressive strength, porosity and accelerated corrosion with impressed voltage (ACTIV) were tested. The results show that the use of ternary blend of OPC, RHA and FA produces mortars with improved strengths at the low replacement level with RHA and FA and at the later age in comparison to that of OPC mortar. The porosity of mortar containing pozzolan reduces with the low replacement level of up to 20% of pozzolan, but increases with the 40% replacement level. The chloride induced corrosion resistance of mortar as measured by ACTIV is, however, significantly improved with the use of both single pozzolan and the ternary blend OPC, RHA and FA. The corrosion resistance of ternary blend mortar is higher than that of mortar containing single pozzolan. The use of ternary blend OPC, RHA and FA is very effective in enhancing chloride induced corrosion of mortar

Influence of Portland Cement Replacement and Sand to Binder Ratio on Slant Shear Strength between Concrete Substrate and Geopolymer

บทคัดย่อบทความนี้ศึกษาอิทธิพลของการแทนที่ปูนซีเมนต์ปอร์ตแลนด์และอัตราส่วนทรายต่อวัสดุประสานที่มีต่อกำลังรับแรงเฉือนอัดระหว่างคอนกรีตกับจีโอโพลิเมอร์มอร์ต้าร์ โดยเถ้าลอยถูกแทนที่ด้วยปูนซีเมนต์ปอร์ตแลนด์   ร้อยละ 0, 5, 10 และ 15 และทำการแปรผันอัตราส่วนทรายต่อวัสดุประสานเท่ากับ 1.00, 1.25 และ 1.50 สารละลายด่างที่ใช้ในการเกิดปฏิกิริยาได้แก่ สารละลายโซเดียมซิลิเกตและสารละลายโซเดียมไฮดรอกไซด์เข้มข้น 6 โมลาร์ โดยใช้อัตราส่วนสารละลายโซเดียมซิลิเกตต่อสารละลายโซเดียมไฮดรอกไซด์เท่ากับ 2.0 อัตราส่วนของเหลวต่อวัสดุประสานเท่ากับ 0.60 และบ่มที่อุณหภูมิห้องทุกอัตราส่วนผสม ผลการทดสอบแสดงให้เห็นว่ากำลังรับแรงเฉือนอัดระหว่างคอนกรีตกับจีโอโพลิเมอร์มอร์ต้าร์มีแนวโน้มเพิ่มขึ้นตามปริมาณการแทนที่ปูนซีเมนต์ปอร์ตแลนด์ที่เพิ่มขึ้น อัตราส่วนทรายต่อวัสดุประสานที่เพิ่มขึ้นส่งผลให้กำลังรับแรงเฉือนอัดระหว่างคอนกรีตกับจีโอโพลิเมอร์มอร์ต้าร์    มีแนวโน้มเพิ่มขึ้น แต่อย่างไรก็ตามเมื่อใช้อัตราส่วนทรายต่อวัสดุประสานเท่ากับ 1.50 กำลังรับแรงเฉือนอัด มีแนวโน้มลดลง ซึ่งปริมาณการแทนที่ปูนซีเมนต์ปอร์ตแลนด์ในเถ้าลอยร้อยละ 15 และอัตราส่วนทรายต่อ วัสดุประสานเท่ากับ 1.00 เป็นอัตราส่วนที่สามารถให้ค่ากำลังรับแรงเฉือนอัดระหว่างคอนกรีตกับจีโอโพลิเมอร์ได้สูงสุดAbstractThis article presents the influence of both Portland cement replacement and sand to binder ratio (S/B) on slant shear strength between concrete substrate and geopolymer mortar. Fly ash (FA) was replaced with Portland cement (PC) at the dosages of 0, 5, 10 and 15% with various sand to binder ratios of 1.00, 1.25 and 1.50, respectively. The alkali solution for used as liquid alkali were sodium silicate (Na2SiO3) and 10 molar sodium hydroxide (NaOH) solutions. The Na2SiO3/NaOH ratio of 2.0 and the liquid/binder (L/B) ratio of 0.60 and cure at ambient temperature were used in all mixture. Test results indicated that the slant shear strength between concrete substrate and geopolymer mortar tends to increase with increase in PC replacement. While the S/B ratio increased, the slant shear strength between concrete substrate and geopolymer mortar tends to increase. However at S/B ratio of 1.50, the slant shear strength tends to decrease. The 15% PC replacement with S/B ratio of 1.00 gave the highest slant shear strength between concrete substrate and geopolymer

Influence of fly ash fineness on water requirement and shrinkage of blended cement mortars

In this paper, the influence of fly ash fineness on water requirement and shrinkage of blended cement mortar was studied. The results indicate that the water requirement and shrinkage characteristic of the blended cement mortar are dependent on fly ash fineness and replacement level. The use of coarse fly ash slightly reduces the water requirement but greatly reduced the drying and the autogenous shrinkage of the blended cement mortars and the reduction is more with an increase in the fly ash replacement level. The finer fly ashes further reduce the water requirement, but increase the drying and the autogenous shrinkages as compared with coarser fly ash. The incorporation of superplasticizer drastically reduces the water requirement, but the effect on the drying and autogenous shrinkages of the normal Portland cement mortar is small. However, for the fly ash mortar, the use of superplasticizer results in a decrease in drying shrinkage and in a substantial increase in the autogenous shrinkage particularly for the fine fly ash at a high replacement level

Effect of grinding on chemical and physical properties of rice husk ash

The effect of grinding on the chemical and physical properties of rice husk ash was studied. Four rice husk ashes with different finenesses, i.e. coarse original rice husk ash (RHA0), RHA1, RHA2, and RHA3 were used for the study.The effect of grinding on the chemical and physical properties of rice husk ash was studied. Four rice husk ashes with different finenesses, i.e. coarse original rice husk ash (RHA0), RHA1, RHA2, and RHA3 were used for the study. Ordinary Portland cement (OPC) was partially replaced with rice husk ash at 20% by weight of binder. The water to binder ratio (W/B) of the mortar was maintained at 110%±5% with flow table test. Specific gravity, fineness, chemical properties, compressive strength, and porosity test of mortars were determined. The differences in chemical composition of the rice husk ashes with different finenesses from the same batch are small. The use of RHA3 produces the mortars with good strength and low porosity. The strength of the mortar improves with partial replacement of RHA3 in comparison with normal coarse rice husk ash. The use of RHA3 results in a strong and dense mortar, which is due to the better dispersion and filling effect, as well as an increase in the pozzolanic reaction

Properties of fly ash geopolymer paste containing Portland cement

AbstractThis article presents the effect of ordinary Portland cement (OPC) replacement on low calcium fly ash (FAF)and high calcium fly ash (FAC) geopolymer paste. Fly ash was replaced with OPC at the rate of 5, 10 and 15% by weightof binder. Sodium silicate (Na2SiO3) and 10 molar sodium hydroxide (NaOH) solutions were used as the alkaline solutionin the reaction. The Na2SiO3/NaOH ratio of 0.67 and the liquid/binder (L/B) ratio of 0.50 and the curing at ambienttemperature were used for all of mixtures. The results found that the level replacement of OPC increase showed thecompressive strength tended to increased. The compressive strength of low calcium fly ash (FAF) and high calcium flyash (FAC) geopolymer paste at 7 days with 15% OPC replacement were 22 and 34 MPa, respectively. In addition, themicrostructure analysis indicated that the increase of OPC replacement resulted in the addition formation of calciumsilicate hydrate co-exists with the aluminosilicate geopolymer products. This results lead to overall increase in thecompressive strength of fly ash geopolymer products