Experimental assessment of appropriate time for aggregate exposure at the surface of cement concrete pavement

ABSTRACT

Exposed aggregate concrete (EAC) pavement is a commonly employed technology in Europe for the construction of highways. The technical challenges associated with pavement construction include achieving both a comfortable ride and the desired skid resistance, while ensuring the long-term concrete durability. Maintaining uniformity of concrete mix, precise dosing of retarding agents, optimal selection of brushing time, and ensuring adequate curing conditions are identified as critical factors for achieving the designed ride performance. This study is focused on determining the appropriate time for the brushing operation, conducted to expose aggregate grains at the surface of the pavement. Laboratory tests were performed on concrete mixes designed to replicate job mixes for the upper layer of a two-layer concrete pavement. Measurements of the mass of evaporated water from the cement paste, isothermal calorimetry tests, and modified Vicat tests were employed to predict the appropriate brushing time. The texture depth was determined using a laser profiler as a function of brushing time. Compressive strength, the rate of chloride ion migration, and scaling resistance were determined through tests conducted on specimens cut from exposed aggregate slabs. Results revealed the suitability of the developed test method for determining the appropriate time for brushing EAC pavements.

KEYWORDS:

• Cement setting
• exposed aggregate concrete
• macrotexture
• pavement durability
• surface retarder
• texturing technology

Acknowledgement

This work was supported by the National Centre for Research and Development (NCBiR) and the General Directorate for National Roads and Motorways (GDDKiA) in Poland under Grant RID-I-37 ‘Alkali-Aggregate Reactivity of Domestic Aggregates’.

Disclosure statement

No potential conflict of interest was reported by the author(s).