Abstract

Objective The study compares the performance of ordinary Portland cement concrete （OPCC）with those incorporating fly ash or slag， and fly ash-based concrete sewage pipes that utilize a fly ash-slag matrix.

Methods Four concrete specimens incorporating different mix ratios of fly ash or slag were produced （FS0， F20， S20， and FS20）. The mechanism for the sulfuric aciderosion of concrete involves the reaction of sulfuric acid with the internal calcium in the concrete，forming non-binding SiO₂·H₂O.Based on this corrosion mechanism， different concrete mix ratios incorporating fly ash and slag as mineral admixtures were designed. Subsequently， a sulfuric acid corrosion environment was simulated using a dry and wet acid cycle， and the sulfuric acid corrosion resistance of both ordinary silicate concrete and the designed fly ash-slag-based concrete was compared. Additionally， sulfuric acid immersion corrosion experiments were conducted. Finally， the soaked specimens were tested using XRD and SEM.

Results and Discussion In this research， a comprehensive examination was conducted on the performance of diverse concretes under sulfuric acid corrosion conditions.Based on the specimen performance metrics， the results indicated that FS20 exhibited the bestresistance to chlorine ion penetration. Notably， its electrical flux was 8.7% lower than that of FS0. This superior performance could be attributed to the mineral admixtures in FS20， which reduced cement content and minimized the formation of expansive products， yielding a more compact structure. Mercury intrusion porosimetry （MIP） test results showed that the incorporation of fly ash and slag led to a decline in total porosity， with FS20 being the densest due to secondary hydration reactions.When assessing the morphologies of specimens before and after sulfuric acid corrosion，FS20 demonstrated the highest corrosion resistance， followed by F20， and S20 outperformed FS0. This improved resistance was attributed to the pozzolanic effect of fly ash and the stability of the calcium-silicate-hydrate （C-S-H）. FS20 consistently exhibited the lowest mass loss rate， as its mineral admixtures effectively reduced the production of expansive products and enhanced densification. The compressive strength of FS20 surpassed that of FS0. Even after 120 days of immersion， despite a 47.0% reduction in strength for FS20， the compressive strength loss rate remained lower than that of FS0. XRD analysis confirmed that FS20 produced fewer expansive minerals.

Conclusion This study systematically investigates the properties of ordinary OPCC，concrete with individual additions of fly ash or slag，and fly ash-slag composite concrete under sulfuric acid immersion. Compared with OPCC， fly ash-slag concrete demonstrates superior corrosion resistance to sulfuric acid. Based on the test results and discussions， the following conclusions are drawn：1） Although the individual inclusion of fly ash or slag reduced the 28-day compressive strength of concrete compared toOPCC，their combined utilization hada synergistic effect. Specifically，the pore structure of the concrete was optimized， chloride ion permeability was significantly improved， and the structural density was further improved.2） After sulfuric acid corrosion， the surface of fly ash-slag-based concrete specimens exhibited no apparent damage.Their mass loss rate and compressive strength loss rate were 1.5% and 4.5% lower than those of ordinary OPCC.3） Upon corrosion， the primary minerals in fly ash-slag-based concrete were calcium and a small amount of gypsum. The composite addition of fly ash and slag reduced the formation of expansive minerals， thereby reducing the risk of concrete cracking due to expansion.This effect impeded the development of corrosion channels through expansion and enhanced the concrete’s resistance to sulfuric acid corrosion.

Keywords： fly ash-slag-based concrete； sulfuric acid corrosion； durability； microstructure

Get Citation:QIAO Yulei， YU Chenxin， ZHANG Xiuzhi， et al. Comparative study on effects of fly ash and slag on anti‑sulfuric acid corrosion performance of concrete［J］. China Powder Science and Technology， 2026， 32（3）： 1-13.

Received: 2025-02-14 .Revised: 2025-05-12,Online: 2025-08-30.

Funding Project:国家重点研发计划项目， 编号： 2022YFE0208200； 内蒙古自治区科技计划项目， 编号： 2022YFHH0118。

First Author:乔玉磊（1999—），男，硕士生，研究方向为混凝土抗硫酸侵蚀性能。E-mail：19861824518@163.com。

Corresponding Author:段广彬（1983—），男，教授，博士，硕士生导师，研究方向为固废综合利用。E-mail：mse_duangb@ujn.edu.cn。

DOI：10.13732/j.issn.1008-5548.2026.03.010

CLC No:TU5； TU528.33； TB4          Type Code: A

Serial No:1008-5548（2026）03-0001-13