تحديد خواص المزيج الاسفلتي شبة المرن المحسن بحقين اسمنتي مع مستحلب اسفلتي

CHARACTERIZING A SEMI-FLEXIBLE MIXTURE INCORPORATING MODIFIED CEMENT –EMULSION GROUT

Abstract

Early distresses such as “rut, cracking, fatigue, etc.” are common on traditional asphalt roads as traffic flow and traffic loads increase dramatically. Therefore, extensive research efforts have been conducted to offer pavement mixture alternatives that show better performance than tradition mixtures. Semi-flexible pavement (SFP) with open-graded matrix asphalt mixture, constructed with (25-35) % air voids filled with special cementitious grout materiel, has been proposed as one of the best alternatives, whereas pavement performance under such mixtures shows extended life of roadways. SFP is widely utilized in many countries because of its superior mechanical qualities, high temperature resistance, and great fatigue resistance, It is characterized by the flexibility of asphalt concrete pavement and the rigidity of cement concrete pavement, It reducing early distresses produced by increased traffic flow and traffic loads.
The primary aim of this research is to develop SFP performance by balancing the rigidity and flexibility of the developed mixtures. The developed SFPs were designed from local materials, including an assessment of the contribution of cementitious grout components and their effect on SFP performance. Ordinary Portland cement (OPC), silica fume (SF), emulsion (EM), superplasticizer (SP), and water were used to make the grout mixtures.
Results show that “flow time” decreases with increasing water percentage, while it is increased with an increase in the emulsion percentage. The compressive strength increases with the increase in age, and the highest compressive strength is associate to 40% Water/binder (W/B) ratio. Also, the flexural strength decreases with the increase in the percentage of EM. Furthermore, low density polyethylene polymer was used to prepare the cylindrical and slab samples using an amount equal to 3%under an air voids content of about 32% within the range of allowed values. The cementitious grout mixes were made and applied to the porous asphalt mixture specimens, with cementitious grout materials completely penetrating all of them. However, indirect tensile strength (ITS), creep compliance test (CCP), wheel track test (WTT), dynamic stability (DS), Cantabro loss test (CLT), skid resistance, and durability tests in terms of water sensitivity (TSR) and ageing were conducted to assess SFP mixtures performance. Results show that the (ITS), for example, increases with the increase age, where optimum mix ingredients can achieve such increment with no EM. Almost similar results were recognized for the tensile examination of the creep compliance test, the dynamic stability, Cantabro loss% and the wheel track test. Inversely, the skid resistance test is associated with the mixture that contains 20% EM, whereas TSR highest value is associated with 60% of EM, reaching up to 88.7%.
Finally, as a main conclusion, using a small amount of emulsion up to 20% with optimum other SFP ingredients plays a vital role in improving the SFP mixture and suggests high performance material in roads construction.