The impact of plasticizer type on frost resistance of road concrete

Insufficient frost resistance of road concrete is one of the main reasons for the low average service life of highway bridges and the rapid deterioration of paving slabs, curbs, etc. The well-known criteria for producing highly frost-resistant concrete - a water-cement ratio (W/C) of less than 0.4 and a volume fraction of entrained air in the concrete mix of 4-8% - are often improperly applied in practice, leading to negative consequences for the concrete structure. By using various su-perplasticizers in mixtures that achieve a W/C ratio of <0.4, manufacturers may neglect other durability factors, believing that this guarantees the quality of the resulting concrete, particularly its increased frost resistance. According to the road concrete tests conducted in this study, one of the most widely used superplasticizers (C3) failed to provide high frost resistance even at a water/ce-ment ratio of <0.4. This is because the presence of C3 in the concrete mix prevents the formation of reserve porosity in the concrete, even with the use of air-entraining admixtures, resulting in reduced frost resistance. In contrast, a polycarboxylate superplasticizer, combined with an air-entraining admixture, provided a high reserve porosity and high frost resistance in the concrete.