Research on manufacturing self-compacting lightweight concrete from fly ash

Abstract

Research on manufacturing artificial lightweight aggregate (LWA) from local materials and fly ash from thermal power plants in the Mekong Delta region by cold-bonded method. Through tests showing that it is possible to produce lightweight aggregate from fly ash of unit weight (1,002 g/cm³), the water absorption of artificial aggregate reaches 15.67 % higher than natural stone (5.21 %) and compressive strength of LWA produced shows 1.08 MPa with a binder content of 8 % and artificial LWA applied to replace 100 % of the volume of crushed stone in SCC mixtures with different w/cm ratios. The results show that self-compacting lightweight concrete produced in the study has a high slump in the range of 250 mm to 270 mm and the sloping diameter from 550 mm to 650mm meets the requirement of self-compacting concrete according to Vietnamese standard 12209:2018, unit weight of self-compacting lightweight concrete with the ratio w/cm (0.23, 0.35 and 0.4) is 12 % to 16% smaller than the case of concrete mix using natural stone. Low water absorption and compressive strength approximately 90 % to 97 % compared to concrete mixes using natural stone and all lightweight concrete are manufactured to ASTM C330 and ACI 318 standards. The results of analysis and evaluation of properties of LWA and self-compacting lightweight concrete produced in the study, it is possible to demonstrate the potential of fly ash application in LWA production and self-compacting lightweight concrete manufacturing combined with mineral additives (Fly ash, silica fume) instead of cement in the study to significantly improve the properties of concrete.