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Properties of pervious concrete containing high-calcium fly ash
V. Sata,C. Ngohpok,P. Chindaprasirt 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.17 No.3
This paper presents the properties of pervious concrete containing high-calcium fly ash. The water to binder ratios of 0.19, 0.22, and 0.25, designed void ratios of 15, 20, and 25%, and fly ash replacements of 10, 20, and 30% were used. The results showed that the use of fly ash as partial replacement of Portland cement enhanced the mixing of paste resulting in a uniform mix and reduced amount of superplasticizer used in the mixture. The compressive strength and flexural strength of pervious concrete were slightly reduced with an increase in fly ash replacement level, while the abrasion resistance increased due mainly to the pozzolanic and filler effects. The compressive strength and flexural strengths at 28 days were still higher than 85% of the control concrete. The aggregate size also had a significant effect on the strength of pervious concrete. The compressive strength and flexural strength of pervious concrete with large aggregate were higher than that with small aggregate.
Efficiency factor of high calcium Class F fly ash in concrete
V. Sata,P. Khammathit,P. Chindaprasirt 사단법인 한국계산역학회 2011 Computers and Concrete, An International Journal Vol.8 No.5
This paper studied the cement efficiency factor (k factor) of high calcium Class F fly ash. This k factor represents a unit of fly ash with efficiency equivalent to k unit of cement. The high calcium Class F fly ash was used to replace cement in concrete. The modified Bolomey’s law with linear relationship was used for the analysis of the result of compressive strength, cement to water ratio (c/w) and fly ash to water ratio (f/w) by using the multi-linear regression to determine the k factor and other constants in the equations. The results of analysis were compared with the results from other researcher and showed that the k factor of high calcium Class F fly ash depends on the fineness of fly ash, replacement level and curing age. While the amount of CaO content in Class F fly ash not evident. Furthermore, necessary criteria and variables for the determination of the k factor including the use of the k factor in concrete mix design containing fly ash were proposed.
佐多敏之,笹本忠,李弘林 연세대학교 산업기술연구소 1981 논문집 Vol.13 No.1
MgO single crystal wafers were subjected to vaporization over the temperature range of 1548 to 1928 K in the H₂-H₂O atmospheres. The vapor pressures of Mg over the solid MgO were obtained from the weight losses of MgO, and the weight losses were measured by the transpiration technique. A comparison of the measured vapor pressures of Mg with the theoretical values calculated by the use of themodynamic data concluded that in this experimental condition MgO vapoizes as follows: MgO(s)+H₂(g)=Mg(g)+H₂O(g)
Jeff C. Gadsden,Siddharth Sata,W. Michael. Bullock,Amanda H. Kumar,Stuart A. Grant,Joshua R. Dooley 대한마취통증의학회 2020 Korean Journal of Anesthesiology Vol.73 No.5
Background: Multiple comparative studies report that adductor canal blocks provide similar pain relief to femoral nerve blocks following total knee arthroplasty. However, adductor canal blockade fails to anesthetize several important femoral nerve branches that contribute to knee innervation. We sought to clarify this anatomic discrepancy by performing both blocks in sequence, using patients as their own controls. We hypothesized that patients would experience additional pain relief following a superimposed femoral nerve block, demonstrating that these techniques are not equivalent. Methods: Sixteen patients received continuous adductor canal block before undergoing knee arthroplasty under general anesthesia. In the recovery room, patients reported their pain score on a numeric scale of 0–10. Once a patient reached a score of five or greater, he/she was randomized to receive an additional femoral nerve block using 2% chloroprocaine or saline sham, and pain scores recorded every 5 min for 30 min. Patients received opioid rescue as needed. Anesthesiologists performing and assessing block efficacy were blinded to group allocation. Results: Patients randomized to chloroprocaine versus saline reported significantly improved median pain scores 30 min after the femoral block (2.0 vs. 5.5, P < 0.001). Patients receiving chloroprocaine also required significantly fewer morphine equivalents during the 30 min post-femoral block (1.0 vs. 4.5 mg, P = 0.032). Conclusions: Adductor canal block is a useful technique for postoperative pain following total knee arthroplasty, but it does not provide equivalent analgesic efficacy to femoral nerve block. Future studies comparing efficacy between various block sites along the thigh are warranted.
Chanchai Ngohpok,Vanchai Sata,Thaned Satiennam,Pongrid Klungboonkrong,Prinya Chindaprasirt 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.4
This paper presents the effect of replacement level of natural aggregate (crushed limestone aggregate, LS) with Recycled Concrete(RC) and coal Bottom Ash aggregates (BA) on pervious concrete properties. Mechanical properties, thermal conductivity, and soundabsorption of pervious concrete were tested. Results showed that the compressive strength of BA pervious concrete was excellentand comparable to that of LS pervious concrete. While the compressive strength of RC pervious concrete was slightly reduced tobetween 85 and 99% of that of LS pervious concrete. The thermal conductivity and sound absorption of pervious concretescontaining RC and BA were significantly improved compared to those of pervious concretes containing conventional LS.
The effects of replacement fly ash with diatomite in geopolymer mortar
Theerawat Sinsiri,Tanakorn Phoo-ngernkham,Vanchai Sata,Prinya Chindaprasirt 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.9 No.6
This article presents the effect of replacement fly ash (FA) with diatomite (DE) on the properties of geopolymer mortars. DE was used to partially replace FA at the levels of 0, 60, 80 and 100% by weight of binder. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions were used as the liquid portion in the mixture in order to activate the geopolymerization. The NaOH concentrations of 15M, Na2SiO3/NaOH ratios of 1.5 by weight, and the alkaline liquid/binder (LB) ratios by weight of 0.40, 0.50, 0.60 and 0.70 were used. The curing at temperature of 75oC for 24 h was used to accelerate the geopolymerization. The flows of all fresh geopolymer mortars were tested. The compressive strengths and the stress-strain characteristics of the mortar at the age of 7 days, and the unit weights were also tested. The results revealed that the use of DE to replace part of FA as source material in making geopolymer mortars resulted in the increased in the workability, and strain capacity of mortar specimens and in the reductions in the unit weights and compressive strengths. The strain capacity of the mortar increased from 0.0028 to 0.0150 with the increase in the DE replacement levels from 0 to 100%. The mixes with 15M NaOH, Na2SiO3/NaOH of 1.5, LB ratio of 0.50, and using 75oC curing temperature showed 7 days compressive strengths 22.0-81.0 MPa which are in the range of normal to high strength mortars.
Investigation of Properties of Lightweight Concrete with Calcined Diatomite Aggregate
Patcharapol Posi,Surasit Lertnimoolchai,Vanchai Sata,Tanakorn Phoo-ngernkham,Prinya Chindaprasirt 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.5
This paper reports the investigation of the properties of Lightweight Concrete (LWC) made from Portland cement and diatomiteaggregate. The chemical and physical properties of diatomite and the mechanical properties of LWC with regard to the effects ofcalcined temperature and gradation were studied. The uncalcined diatomite was crushed and calcined at 400, 600, and 800°C for 4hours and used as lightweight aggregate. A constant Water to Cement ratio (W/C) of 2.0 and Aggregate to Cement ratio (A/C) of 1.6were used for all mixes. The 28-day compressive strength of LWC of 6.4-11.9 MPa, porosity and water absorption of 34.0-49.4%,modulus of elasticity of 2.0-4.3 GPa, thermal conductivity of 0.166-0.192 W/mK, and unit weight of 1170-1300 kg/m3 wereobtained. The results indicated that the strength of concrete increased when the calcined temperature of diatomite and the amount ofsmall-size aggregate were increased. The increase in temperature ridded the burnable elements and improved the properties ofdiatomite. The small-size aggregate produced good matrix-aggregate bonding and enhanced the strength of concrete. The calcineddiatomite could, therefore, be used as good aggregate in making lightweight concrete.