Issue 52

H. Latifi et alii, Frattura ed Integrità Strutturale, 52 (2020) 211-229; DOI: 10.3221/IGF-ESIS.52.17

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c) d) Figure 12: SEM photos; a) HMA @ 2.5 k x, b)HMA @ 2.5 k x, c) Portland cement @ 5 k x, d)CRMA @ 4.7 k x

C ONCLUSIONS

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n this study Portland cement and acrylic polymer were used as additives to improve the moisture susceptibility of CMA. To evaluate the effectiveness of this modification, SFE test and mechanical tests were conducted on modified CMA as main studied mixtures and unmodified CMA and HMA as reference mixtures. Asphalt mixtures were made with different combinations of binder and aggregates. The following conclusions could be drawn from the performed study:  Lower Lifitz-van der Waal component of asphalt emulsion compared to PG 64-28 asphalt binder led to weaker SFE and consequently aggregates- binder adhesion.  Addition of Portland cement (PC) and Acrylic Polymer (AP) to the asphalt emulsion increased acid-base component of SFE asphalt emulsion. Increased acid-base component led to higher free energy of adhesion for modified CMAs and consequently adhesion of cold mix asphalts improved.  The findings showed that cement and acryl polymer additives improved resistance of different studied mixtures, specifically, cold recycled mix asphalt against moisture damage by improving the adhesion between aggregate and asphalt.

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