MgO expansive cement and concrete in China: Past, present and future

• Review on near 40 years' research history of MgO expansive cement and concrete
• Review on the state-of-the-art progress in the field of MgO cement and concrete
• Review on future work needs for extending application of MgO cement and concrete
• Review on production, property design, and application of MgO in cement materials
• Review on mechanical performance, durability, and soundness of MgO concrete

Uniquely, China employs MgO already contained in cement clinker or as an expansive additive to compensate for the thermal shrinkage of mass concrete, particularly dam concrete, with almost 40 years' experience in both research activities and industrial applications. Compensating shrinkage with expansion produced by MgO has been proved to effectively prevent thermal cracking of mass concrete, and reduce the cost of temperature control measures and speed up the construction process. Moreover, the expansion properties of MgO could be designed flexibly, through adjusting its microstructure by changing the calcination conditions (calcining temperature and residence time). The collective knowledge and experience of MgO expansive cement and concrete is worthy of sharing with relevant engineers and researchers globally but dissemination has been hindered as most of the relevant literature is published in Chinese. This paper reviews the history, state-of-the-art progress and future research needs in the field of MgO expansive cement and concrete.