SAP对碱激发泡沫混凝土自收缩与热力学性能的影响

doi:10.16552/j.cnki.issn1001-1625.2026.0127

摘要/Abstract

摘要：

碱激发泡沫混凝土（AAFC）具有轻质高强、保温隔热等优势，但收缩开裂风险高的本征缺陷限制了其在实际工程中的应用。本研究以矿渣为主要凝胶材料，系统探究了高吸水树脂（SAP）的形态与吸/释水行为对AAFC工作性能、自收缩、抗压强度及导热系数的影响规律，并结合TG、SEM、¹H NMR及毛细管压力等测试揭示其作用机制。结果表明：高吸水倍率、不规则形状的聚丙烯酸钠SAP（SAP-A）的掺入将急剧增大浆体的屈服应力与塑性黏度，显著增加孔径为500 μm以上大孔的比例，导致AAFC的28 d抗压强度较未添加SAP的空白组降低了30.5%；吸水倍率适中、球形结构的丙烯酸-丙烯酰胺共聚SAP（SAP-M）的引入有利于气泡的均匀分散，优化孔径分布，保证AAFC强度稳定发展并降低导热系数至0.089 W/（m·K）。此外，SAP-M在终凝之后快速释水，3 d释水量较SAP-A增加32.6个百分点，有效减缓了毛细管压力的发展，自收缩抑制效率提升了28.7%。

关键词: 碱激发泡沫混凝土, 高吸水树脂（SAP）, 自收缩, 抗压强度, 导热系数, 微观结构

Abstract:

Alkali-activated foam concrete （AAFC） possesses multiple advantages， including low density， high strength， and excellent thermal insulation. However， its inherent susceptibility to shrinkage cracking remains a critical drawback that hinders widespread practical application. This study systematically investigated the effects of the morphology and water absorption/release behavior of superabsorbent polymer （SAP） on the workability， autogenous shrinkage， compressive strength， and thermal conductivity of AAFC using ground granulated blast-furnace slag as the primary binder. The underlying mechanisms were elucidated through thermogravimetric analysis （TG）， scanning electron microscopy （SEM）， low-field ¹H nuclear magnetic resonance （¹H NMR）， and capillary pressure measurements. The results demonstrate that the addition polyacrylate SAP （SAP-A）， characterized by a high-water absorption capacity and irregular morphology， significantly increases the yield stress and plastic viscosity of the paste， markedly raises the proportion of pores larger than 500 μm in diameter， and ultimately leads to a 30.5% reduction in the 28 d compressive strength of AAFC compared to the control group without SAP. In contrast， the incorporation of acrylic acid-acrylamide copolymer SAP （SAP-M）， which exhibits a moderate water absorption capacity and spherical structure， facilitates uniform dispersion of bubbles. This optimizes the pore structure， thereby enabling the steady development of strength while reducing the thermal conductivity of AAFC to 0.089 W/（m·K）. Furthermore， SAP-M rapidly releases its absorbed water after final setting， achieving a 32.6 percentage point higher cumulative water release at 3 d compared to SAP-A. This behavior effectively alleviates the development of capillary pressure and enhances the autogenous shrinkage mitigation efficiency by 28.7%.

Key words: alkali-activated foam concrete, superabsorbent polymer （SAP）, autogenous shrinkage, compressive strength, thermal conductivity, microstructure

中图分类号:

TU528.2

李明明, 姜东兵. SAP对碱激发泡沫混凝土自收缩与热力学性能的影响[J]. 硅酸盐通报, 2026, 45(8): 2686-2698.

LI Mingming, JIANG Dongbing. Effect of SAP on Autogenous Shrinkage and Thermodynamic Properties of Alkali-Activated Foam Concrete[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(8): 2686-2698.

图/表 16

表1 矿渣的主要化学组成

Table 1 Main chemical composition of GGBS

Chemical composition	CaO	SiO₂	Al₂O₃	MgO	SO₃	Na₂O	Fe₂O₃	Other	LOI
Mass fraction/%	30.54	33.98	18.80	12.24	2.11	0.67	0.20	0.40	1.06

图1 SAP的微观形貌与粒度分布

Fig.1 Micromorphology and particle size distribution of SAP

表2 发泡剂的基本参数

Table 2 Foaming agent parameters

Parameter	Dilution multiple	Foaming multiple	Bleeding water/g	Settlement distance/mm	Half-life/h
Value	1∶60	20.6	39.4	2.0	8.5

表3 SAP-M的合成参数

Table 3 Synthetic parameters of SAP-M

Sample No.	AA mass/g	NaOH mass/g	AM mass/g	KPS mass/g	MBA mass/g	Span60 mass/g	HJW volume/mL
SAP-M	0.600	0.250	5.400	0.054	0.006	2.772	90

图2 SAP在不同溶液中的吸水性能及其吸水后的宏观图片

Fig.2 Absorption capacities of SAP in different solutions and macroscopic images after water absorption

表4 AAFC的配合比

Table 4 Mix proportion of AAFC

Sample No.	Mass/kg
Sample No.	GGBS	NaOH	Na₂SiO₃	Water	Foam	SAP-A	SAP-M
C	351.60	20.22	110.46	63.16	52.74	—	—
CSA	351.60	20.22	110.46	63.16	52.74	1.76	—
CSM	351.60	20.22	110.46	63.16	52.74	—	1.76

图3 SAP改性碱激发浆体的流变性能与AAFC的流动度

Fig.3 Rheology of alkali-activated pastes with SAP and fluidity of AAFC

图4 SAP对AAFC凝结时间的影响

Fig.4 Effect of SAP on setting time of AAFC

图5 SAP对AAFC自收缩的影响

Fig.5 Effect of SAP on autogenous shrinkage of AAFC

图6 SAP对AAFC抗压强度与导热系数的影响

Fig.6 Effect of SAP on compressive strength and thermal conductivity of AAFC

图7 AAFC养护28 d的TG/DTG曲线

Fig.7 TG/DTG curves of AAFC cured 28 d

表5 各试样C（N）-A-S-H凝胶（Mg）、类水滑石相（Mh）与碳酸钙（Mc）的质量损失

Table 5 Mass loss of C（N）-A-S-H gels （Mg）， hydrotalcite-like phases （Mh） and CaCO3 （Mc） in each sample

Sample No.	Mass loss/%
Sample No.	Mg （50~250 ℃）	Mh （275~425 ℃）	Mc （600~900 ℃）
C	13.97	5.48	3.07
CSA	13.29	5.34	2.65
CSM	13.91	5.63	1.78

图8 SAP对AAFC孔结构的影响

Fig.8 Effect of SAP on pore structure of AAFC

图9 SAP改性AAFC的SEM照片

Fig.9 SEM images of SAP-modified AAFC

图10 碱激发浆体的T2分布和不同类型水的信号分数随水化时间演变规律

Fig.10 Evolution law of T2 distribution and signal fractions of different types of water versus hydration time for alkali-activated pastes

图11 SAP对AAFC毛细管压力的影响

Fig.11 SAP on capillary pressure of AAFC

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