Most ready-mixed concrete plants have a large problem of construction waste sludge, which causes environmental pollution and economic loss. Therefore, the cement sludge recycling system is highly requested. Japanese Industrial Standard(JIS)A 5308 permits the addition of 3% sludge(as solid state)to cement in concrete. However, it is pointed out that the reduction of fluidity and increase of water demand was occurred upon utilization of sludge. To achieve more widespread recycling of sludge by using set-retarders, the evaluation method of residual cement content of sludge needs to be established. The rate of heat liberation of residual ordinary Portland cement in sludge water was measured by using conduction calorimeter. And the residual amount of sodium gluconate in sludge water was measured by Total Organic Carbon Analyzer(TOC). The amount of residual cement in sludge water by XRD quantitative method was related to the heat liberation of residual cement in sludge water. It is concluded that the residual amount of cement in sludge water can be estimated by using conductive type calorimeter. When the Mg(NO₃)₂・6H₂O was added, the retardation of cement hydration by sodium gluconate was decreased. It is considered that the acceleration mechanism of Mg(NO₃)₂・6H₂O is the decrease of sodium gluconate concentration in liquid phase. The amount of residual cement with sodium gluconate in sludge water can be evaluated by using conductive type calorimeter and Mg(NO₃)₂・6H₂O. Furthermore, swift evaluation method of residual cement amount in sludge water is established by using the simulation of heat liberation curve.本研究はスラッジ水中に含まれる残存セメント分を有効活用するため、グルコン酸ナトリウムを用いて水和反応を制御したスラッジ水中に残存しているセメント量を迅速に定量評価する方法を確立することを目的とした。伝導型熱量計を用いて24時間における水和発熱量を測定することで、スラッジ水中の残存セメント分を簡便に推定することを可能とした。また、硝酸マグネシウムを用いてグルコン酸ナトリウムにより水和制御されたセメントの水和を再開させることが可能であることを確認した。さらに水和反応速度シミュレーション法を構築し、10時間程度までの水和発熱速度を測定することでスラッジ水中の残存セメント量を推定することを可能とした。


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  • Accession Number: 01562531
  • Record Type: Publication
  • Source Agency: Japan Science and Technology Agency (JST)
  • Files: TRIS, JSTAGE
  • Created Date: Apr 23 2015 10:50AM