CAJ | 학술논문

通过实验室模拟研究不同湿法存放时间(1～60个月)的2种低钙粉煤灰的形貌、粒径和用于混凝土掺合料的性能变化.粉煤灰湿排后颗粒变粗,颗粒表面出现侵蚀,但颗粒形貌基本保持不变;湿排粉煤灰矿物减水效应明显降低,掺量为20%～40%的湿排粉煤灰混凝土坍落度比原状粉煤灰混凝土减少约20～40 mm;掺加湿排粉煤灰的混凝土与外加剂适应性、抗渗和抗碳化无明显变化,坍落度经时损失有所降低;湿法存放3个月的粉煤灰掺量20%时混凝土28 d和56 d抗压强度比原状粉煤灰混凝土分别下降5.8%和3.7%,但掺量为20%的湿法存放36个月粉煤灰混凝土抗压强度比仍可以达到85%,湿法存放时间为3 a和5 a的粉煤灰混凝土强度无明显差别.研究结果表明,湿排低钙粉煤灰可以用作为混凝土掺合料.
통과실험실모의연구불동습법존방시간(1～60개월)적2충저개분매회적형모、립경화용우혼응토참합료적성능변화.분매회습배후과립변조,과립표면출현침식,단과립형모기본보지불변;습배분매회광물감수효응명현강저,참량위20%～40%적습배분매회혼응토담락도비원상분매회혼응토감소약20～40 mm;참가습배분매회적혼응토여외가제괄응성、항삼화항탄화무명현변화,담락도경시손실유소강저;습법존방3개월적분매회참량20%시혼응토28 d화56 d항압강도비원상분매회혼응토분별하강5.8%화3.7%,단참량위20%적습법존방36개월분매회혼응토항압강도비잉가이체도85%,습법존방시간위3 a화5 a적분매회혼응토강도무명현차별.연구결과표명,습배저개분매회가이용작위혼응토참합료.
Two types of wetting low-calcium fly ash were made for studying the performance under different storage time (1 to 60 months). The surface morphology, granule size distribution of the wetting fly ashes and their properties as supplementary cementitious materials in concrete were investigated. Although the granule size increased and there appeared considerable erosion on the surface, the surface morphology of wetting fly ash kept mostly unchangeable. The water reducing effect resulted from mineral properties of fly ash decreased much due to wetting. Compared with a parallel concrete with dry fly ash, slump of concretes with fly ash of 20～40% wetting for 3 months decreased by 20～40 mm while bleeding and permeability and carbonation had no change. The compressive strength of concrete in 28 day and 60 days with fly ash of 30% wetting for 3 months decreased by 5. 8% and 3. 7% respectively. However, the specific compressive strength of concrete in 56 days with fly ash of 20% wetting for 36 months still reached at 85% and there was no visible strength discrepancy of fly ash concrete wetting for 3 and 5 years. It was concluded that a wetting low-calcium fly ash could be used as supplementary cementitious material in some important concretes.