СТАНДАРТНЫЕ ПОКАЗАТЕЛИ МОДИФИЦИРОВАННЫХ БИТУМОВ

Abstract

The main standard indicators (penetration at 25 °С, ductility at 25 °С, softening point, Fraas point) have been determined and analyzed in this work for bitumens of the grades BND 100-130, BND 130-200 and 21 modified bitumens. The neat bitumens of the grades BND 100-130 and BND 130-200 have been produced at Pavlodar petrochemical plant from the oil of Western Siberia (Russia) by method of direct oxidation and they satisfy the requirements of the standard of Kazakhstan ST RK 1373-2013 “Bitumens and bituminous binders. Oil road viscous bitumens. Technical specifications”. The polymers Elvaloy 4170, Elvaloy AM, Kraton, Calprene 501, Butonal NS 198, SBS (L30-01A), KUMHO, crumb rubber and polyphosphoric acid have been accepted as modifiers. The modification of the bitumens has been performed in the laboratory of Kazakhstan Highway Research Institute (KazdorNII). The manufactured modified bitumens satisfy the requirements of the standard of Kazakhstan ST RK 2534-2014 “Bitumens and bituminous binders. Oil modified road bitumens. Technical specifications”. The standard indicators of the neat and modified bitumens have been determined in the laboratory of KazdorNII according to the following standards of Kazakhstan; penetration at 25 °C - ST RK 1226-2003 “Oil bitumens and binder materials based on bitumen. Method for determination of needle penetration depth”; ductility at 25 °С - ST RK 1374-2005 “Bitumens and bituminous binders. Method for determination of ductility”; softening point - ST RK 1227-2003 ‘Bitumens and bituminous binders. Determination of softening point by ring and ball method”; Fraas point - ST RK 1229-2003 ‘Oil bitumens and bituminous binders. Method for determination of Fraas point”. It is found out that all the applied polymers and polyphosphoric acid when adding them to the bitumens decrease the penetration thereby changing the grade of the bitumens. After modification 43 % of the polymer bitumens convert to the next grade, 43 % change their grade for 2 units and 14 % have the grade more viscous for 3 units. All the considered polymers and polyphosphoric acid increase the softening point thereby improving the high temperature resistance of the bitumens. It is determined that at modification of the bitumens of the grades BND 100-130 and BND 130-200 the increase of the Fraas point is 32-45 % and 28-93 % respectively. Most (71 %) of the polymers and polyphosphoric acid increase the Fraas point (decrease the low temperature resistance). In four cases out of twenty-one (19 %) the modification does not practically vary the Fraas point. The positive effect has been obtained only in two cases (10 %) for the modification of the bitumen of the grade BND 130-200 - the decrease of the Fraas point. The increase of the ductility for the bitumens has been recorded only in three cases (14 %) for their modification. In four cases (19 %) the initial ductility remains constant. In other cases (67 %) the ductility of the bitumens is decreased from 26 % to 86 %.