This paper aims to investigate drying shrinkage, strength and microstructure of alkali-activated high-calcium fly ash (AAHF) paste by using FGD-gypsum (FGD) and dolomite (DLM) as expansive additives. The 10 M sodium hydroxide combined with sodium silicate solutions were used as alkaline activator for all mixes. The preparation of AAHF paste was divided into 2 steps. First, the study focused on the effects of expansive additive (FGD and DLM) and liquid/binder (L/B) ratio on the drying shrinkage of AAHF paste. The fly ash (HF) was replaced with FGD and DLM at the dosages of 0%, 2.5%, 5.0%, 7.5%, and 10% by weight of binder. The drying shrinkage, setting time, compressive strength and microstructure of AAHF paste containing FGD and DLM were studies. Test results showed that the use of FGD and DLM as expansive additives improved the drying shrinkage of AAHF paste. The increasing L/B ratio had an adverse effect on drying shrinkage. The setting time of AAHF paste containing FGD and DLM decreased, whereas the strength increased. However, the strength development of the AAHF paste incorporated with FGD tended to decline at the curing time of 120 days. The increase in strength was due to the formation of some strength-bearing chemical phases which was demonstrated by the XRD, FTIR, and SEM/EDS analyses. The differences in reaction products were an essential factor in the strength development of the AAHF paste with expansive additive. It can be recommended that using DLM was advantages regarding the improvement of drying shrinkage and long-term strength in comparison with the AAHF paste with FGD.

本文旨在研究以烟气脱硫石膏（FGD）和白云石（DLM）为膨胀添加剂的碱活化高钙粉煤灰（AAHF）浆料的干燥收缩率，强度和微观结构。10 M氢氧化钠与硅酸钠溶液的混合物用作所有混合物的碱性活化剂。将AAHF糊剂的制备分为两个步骤。首先，研究集中于膨胀添加剂（FGD和DLM）和液/粘合剂（L / B）比对AHF浆料干燥收缩的影响。用粘合剂含量为0％，2.5％，5.0％，7.5％和10％的FGD和DLM代替粉煤灰（HF）。研究了含有FGD和DLM的AAHF糊的干燥收缩率，凝固时间，抗压强度和微观结构。测试结果表明，使用FGD和DLM作为膨胀添加剂可改善AHF浆料的干燥收缩率。L / B比的增加对干燥收缩有不利影响。包含FGD和DLM的AAHF浆料的凝固时间减少，而强度增加。然而，掺入FGD的AAHF糊剂的强度发展在120天的固化时间趋于下降。强度的增加归因于XRD，FTIR和SEM / EDS分析表明形成了一些具有强度的化学相。反应产物的差异是使用膨胀添加剂的AAHF浆料强度发展的重要因素。可以建议使用DLM与AAGHF糊剂与FGD相比在干燥收缩率和长期强度的改善方面具有优势。