Work

Effect of Combined MgO Expansive Agent and Rice Husk Ash on Deformation and Strength of Post-Cast Concrete

Year: 2025

Type: article

Abstract: This study investigates the effects of the combined addition of MgO expansive agent (MEA) and rice husk ash (RHA) on the performance of concrete. Results show that MEA absorbs water and competes with superplasticizers for adsorption, reducing early-age fluidity. In the later stages, its reaction with RHA generates M-S-H gel, accelerating slump loss. At early ages (up to 7 days), due to the slow hydration of MEA and partial replacement of cement, fewer hydration products are formed. Additionally, the pozzolanic reaction of RHA has not yet developed, resulting in the low early strength of concrete. In the later stages, Mg(OH)2 fills pores and enhances compactness, while the pozzolanic reaction of RHA further optimizes the pore structure. The internal curing effect also provides the moisture needed for continued MEA hydration, significantly improving later-age strength. Moreover, in the post-cast strip of a tall building, the internal curing effect of RHA ensures the effective shrinkage compensation by MEA under low water-to-cement ratio conditions. The restraint provided by reinforcement enhances the pore-filling effect of Mg(OH)2, improving concrete compactness and crack resistance, ultimately boosting long-term strength and durability.

Source: Materials

DOI: 10.3390/ma18122815

Authors: Feifei Jiang, Yijiang Xing, Wencong Deng, Qi Wang, Jialei Wang, Zhongyang Mao

Institutions: Nantong Institute of Technology, China State Construction Engineering (China), Nanjing Tech University

Language: English

Topic: Concrete Properties and Behavior

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $3,137