Effects of Coarse Aggregate Extension on Properties of Rapid-set Prepackaged Repair Materials
The surface distress in concrete structures provides easier pathways for the penetration of water and aggressive chemicals, thus accelerating the deterioration of concrete structures.It also causes serious safety hazards in transportation structures such as pavements and bridge decks due to bumpy ride.As a result, adequate repair is essential to restore the serviceability as well as the water-tightness of concrete structures.Conventional concrete mixes are not preferred for this application due to their relatively slow setting and early strength development.They are particularly inappropriate in areas where heavy traffic volume is expected or congestion is severe.Over the past decades, numerous rapid-set prepackaged repair materials have been developed for patching the surface deterioration of concrete structures, the majority of which can provide acceptable performance, such as good workability, rapid setting, and fast strength development.However, these materials are typically cementitious mortars, which are relatively costly and typically have high dimensional instability due to high paste volume and high early heat evolution.Adding coarse aggregate to mortars would increase the yield and lower the cost.It would also increase the volume stability due to the reduced dry shrinkage and less early heat generation.The intention of this paper is to present how coarse aggregate extension affects the main properties of rapid-set prepackaged patching mortars.Approximately, 16 rapid-set prepackaged cementitious repair products that were commercially available in US were collected in this study.A crushed limestone coarse aggregate with a nominal maximum size of 9.5mm was added to each mortar to evaluate the impacts of aggregate extension on its main properties.It was found that the coarse aggregate extension effectively reduced the dry shrinkage and the shrinkage cracking potential as well as the early heat generation.It also significantly improved the bond capacity of material.However, for most cementitious mortars, adding coarse aggregate reduced their compressive strength and freeze and thaw durability.In addition, the aggregate extension noticeably reduced the permeability for magnesium-phosphate cement-based mortars, while there was a slight increase or no significant effect on the permeability of other cementitious products.
Rapid Set Repair Material Aggregate Extension Strength Bonding Capacity
Zhifu Yang Heather J.Brown Jon Huddleston
School of Concrete and Construction Management, Middle Tennessee State University, Murfreesboro,Tennessee, USA
国际会议
福州
英文
273-282
2018-11-04（万方平台首次上网日期，不代表论文的发表时间）