Jeon Dongho, Yum Woo Sung, Song Haemin, Yoon Seyoon, Bae Younghoon, Oh Jae Eun
School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulju-gun, Ulsan 44919, Korea.
Department of Civil Engineering, Kyonggi University, 154-42, Gwanggyosan-ro, Yeongtong-gu, Suwon-Si, Gyeonggi-do 16227, Korea.
Materials (Basel). 2020 Dec 8;13(24):5598. doi: 10.3390/ma13245598.
This study investigated the use of coal bottom ash (bottom ash) and CaO-CaCl-activated ground granulated blast furnace slag (GGBFS) binder in the manufacturing of artificial fine aggregates using cold-bonded pelletization. Mixture samples were prepared with varying added contents of bottom ash of varying added contents of bottom ash relative to the weight of the cementless binder (= GGBFS + quicklime (CaO) + calcium chloride (CaCl)). In the system, the added bottom ash was not simply an inert filler but was dissolved at an early stage. As the ionic concentrations of Ca and Si increased due to dissolved bottom ash, calcium silicate hydrate (C-S-H) formed both earlier and at higher levels, which increased the strength of the earlier stages. However, the added bottom ash did not affect the total quantities of main reaction products, C-S-H and hydrocalumite, in later phases (e.g., 28 days), but simply accelerated the binder reaction until it had occurred for 14 days. After considering both the mechanical strength and the pelletizing formability of all the mixtures, the proportion with 40 relative weight of bottom ash was selected for the manufacturing of pilot samples of aggregates. The produced fine aggregates had a water absorption rate of 9.83% and demonstrated a much smaller amount of heavy metal leaching than the raw bottom ash.
本研究调查了在使用冷粘结造粒法制造人造细骨料过程中，煤底灰（底灰）和CaO-CaCl活化磨细粒化高炉矿渣（GGBFS）粘结剂的使用情况。制备了相对于无水泥粘结剂（=GGBFS+生石灰（CaO）+氯化钙（CaCl））重量添加量不同的底灰的混合样品。在该体系中，添加的底灰并非简单的惰性填料，而是在早期就会溶解。由于底灰溶解导致Ca和Si的离子浓度增加，硅酸钙水合物（C-S-H）更早且更高水平地形成，这提高了早期强度。然而，添加的底灰在后期阶段（例如28天）并不影响主要反应产物C-S-H和碳铝酸钙的总量，只是加速了粘结剂反应直至反应进行14天。在综合考虑所有混合物的机械强度和造粒成型性后，选择底灰相对重量为40的比例来制造骨料的中试样品。所生产的细骨料吸水率为9.83%，并且与原始底灰相比，重金属浸出量要少得多。
