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摘要:
研究了粉煤灰中铵离子含量对新拌混凝土流动性、混凝土中减水剂掺量及混凝土性能的影响,并采用TOC实验分析了粉煤灰铵离子含量对减水剂吸附量影响。结果表明:随着粉煤灰中铵离子含量的增加,新拌混凝土流动性逐渐降低;混凝土达到相近流动性时,随着粉煤灰中铵离子含量增加,混凝土中减水剂的掺量逐渐增大,混凝土强度均逐渐降低;TOC实验表明粉煤灰中铵离子含量越高对减水剂的饱和吸附量越大。
Abstract:Effects of ammonium ion content in fly ash on the fluidity of fresh concrete, the superplasticizer dosage in concrete and the properties of concrete were studied, and the effect of adsorption on superplasticizer was analyzed by TOC test. Results show that as the content of ammonium ion in fly ash increases, the fluidity of fresh concrete decreases. When maintaining the close fluidity, as the content of ammonium ion in fly ash increases, the superplasticizer dosage in concrete increases, and the strength of concrete decreases. TOC test shows that the higher content of ammonium ion is, the greater adsorption of superplasticizer will be.
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Key words:
- Fly ash /
- Ammonium ion content /
- Superplasticizer dosage /
- Adsorption
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表 1 某电厂脱硝粉煤灰性能
Table 1. Denitration fly ash performance of a power plant
编号 粉煤灰样品 铵离子含量/(g·t-1) 比表面积/(m2·kg-1) 细度(45 µm方孔筛筛余)/% 需水量比/% 活性指数/% 1# 原灰 385 440 16.5 100 80 2# 脱铵处理灰 24 - - 98.4 89 表 2 不同铵离子含量的粉煤灰XRF表征/%
Table 2. XRF characterization of fly ash with different ammonium ion content
编号 铵离子含量* SiO2 Al2O3 Fe2O3 CaO TiO2 SO3 MgO Na2O K2O 1# 385 41.0 39.0 7.70 5.40 1.52 1.38 1.08 0.61 0.57 2# 24 39.7 38.6 8.58 5.87 1.63 1.36 0.99 0.67 0.58 *单位为:g/t 表 3 鱼峰P.Ⅱ42.5硅酸盐水泥性能
Table 3. Yufeng P.Ⅱ42.5 Portland cement properties
型号 熟料 水泥 C3S/% C3A/% f-CaO/% Cl-/% MgO /% SO3/% 烧失
量/%碱含
量/%比表面积/
m2/kg抗折强
度/MPa抗压强
度/MPa3 d 28 d 3 d 28 d P.Ⅱ42.5 51.92 1.90 0.23 0.12 1.64 2.22 0.75 0.38 331 4.2 7.8 19.5 54.7 表 4 混凝土配合比/(kg·m-3)
Table 4. Concrete mix ratio
配比 水 水泥 粉煤灰 矿渣 砂 砂 石 减水剂 水厂 鱼峰水泥厂
PⅡ42.5钦州电厂 钦州蓝岛公司 防城港砂石
厂中砂防城港砂石
5~16 mm防城港砂石厂
16~25 mm苏博特
PCA-1A 165 250 120 50 760 365 700 5.88 B 150 280 130 40 740 365 715 5.85 表 5 对抗氯离子渗透系数的影响
Table 5. Effect of resistance to chloride ion permeability coefficient
铵离子含量/(g·t-1) 减水剂掺量/% 28 d 56 d 100 1.30 - - 150 1.33 3.3 2.9 200 1.36 3.3 3.0 300 1.37 3.9 3.3 表 6 减水剂在粉煤灰颗粒表面的Langmiur等温吸附参数
Table 6. Langmiur isotherm adsorption parameters of water reducing agent on the surface of fly ash particles
编号 铵离子含量/(g·t-1) R2 Intercept/(g·L-1) Slope k/(L·g-1) As/ (mg·g-1) 1# 385 0.996 16.63 1236.81 74.36 0.81 2# 24 0.998 36.10 1693.01 46.90 0.59 -
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