Performance Evaluation of a New Aggregate Gradation for 7% Natural Rubber Modified Asphalt Mixtures

Opukenigara Opukenigara; Elsa Eka Putri; Bayu Martanto Adji; Abdul Hakam

doi:10.2478/cee-2026-0003

Figures & Tables

Gradation of AC-WC for all various gradations.

Volumetric Marshall result (VMA, VIM, VFB, Flow)_

No	Asphalt Content [%]	VMA [%]		VIM [%]		VFB [%]		Flow [mm]		Type of Aggregate Gradation
		ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT
		Specification requirement
		>15 %		3 % – 5 %		>65%		2 mm – 4 mm
1	5%	16.731	16.757	6.345	7.250	62.081	56.895	3.214	4.180	Datum
		17.204	16.281	6.555	6.715	61.919	58.817	2.860	3.360	A
		15.476	16.125	4.658	6.586	69.922	59.309	3.700	3.420	B
		15.590	16.834	3.734	7.176	76.111	57.381	3.560	4.460	C
		15.981	16.964	4.976	7.408	68.898	56.614	3.120	3.860	D
		15.979	17.250	4.887	7.439	69.498	57.039	3.160	4.020	E
2	5.5%	16.272	16.519	5.330	6.493	67.252	60.706	2.730	4.480	Datum
		15.991	16.365	4.685	6.316	70.710	61.766	3.160	3.120	A
		15.446	16.726	4.118	6.765	73.337	59.623	3.660	2.680	B
		15.369	16.651	2.972	6.479	80.834	61.190	3.540	3.340	C
		15.141	16.093	3.517	5.942	77.484	63.162	3.240	3.600	D
		15.904	16.115	4.299	5.673	73.017	64.859	3.200	4.000	E
3	6.%	15.963	16.662	4.474	6.157	71.973	63.096	2.930	3.700	Datum
		16.253	16.274	4.477	5.714	72.482	65.112	3.520	3.940	A
		15.628	16.875	3.817	6.436	75.607	61.917	3.600	3.580	B
		15.894	16.944	3.060	6.312	80.778	62.807	3.500	3.660	C
		15.800	16.335	3.758	5.715	76.482	65.073	3.640	3.300	D
		16.336	16.704	4.284	5.836	73.884	65.556	3.800	4.320	E
4	6.5%	16.309	15.585	3.551	4.436	78.230	71.558	3.370	4.700	Datum
		15.837	15.802	3.489	4.677	77.976	70.450	3.740	4.000	A
		15.671	16.067	3.351	5.021	78.638	68.889	3.400	3.380	B
		15.939	16.479	2.595	5.283	83.744	67.967	3.640	3.820	C
		15.874	16.300	3.328	5.170	79.221	68.402	3.480	3.800	D
		16.263	18.370	3.688	7.227	77.401	60.696	4.020	3.820	E
5	7%	16.495	17.176	4.059	5.732	75.396	66.624	3.726	4.220	Datum
		16.141	16.622	3.320	5.097	79.437	69.377	3.900	4.400	A
		15.953	16.141	3.157	4.594	80.226	72.136	4.440	3.200	B
		16.223	16.829	2.402	5.174	85.201	69.440	4.560	4.420	C
		16.239	16.346	3.230	4.713	80.142	71.220	3.800	3.860	D
		16.809	17.883	3.801	6.172	77.454	65.983	4.140	4.020	E

Aggregate properties_

No.	Properties	Coarse aggregate	Medium aggregate	Fine aggregate	Specification
1.	Bulk specific gravity (gr/cc)	2.682	2.659	2.583	≥ 2.53
2.	Saturated surface dry specific	2.718	2.697	2.647	≥ 2.54
3.	Apparent specific gravity (gr/cc)	2.78	2.764	2.759	≥ 2.63
4.	Absorption (%)	1.315	1.425	1.459	≥ 1.37
5.	Los Angeles, Abrasion (%)	13.11	13.11	-	≥ 30.0

Five trial aggregate gradation_

Sieve No.		Gradation (Datum)	Grad. A	Grad. B	Grad. C	Grad. D	Grad. E	Specification
mm	inch	Gradation (Datum)	Grad. A	Grad. B	Grad. C	Grad. D	Grad. E	Lower limit	Upper limit
% passing
25.40	1″	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00
19.00	3/4″	100.00	100.00	100.00	100.00	100.00	100.00	100.00	100.00
12.50	1/2″	92.32	90.69	89.64	88.59	87.54	86.49	90.00	100.00
9.50	3/8″	86.20	83.44	81.98	80.52	79.06	77.60	77.00	90.00
4.75	#4	62.30	57.71	56.02	54.32	52.62	50.92	53.00	69.00
2.36	#8	35.45	32.92	31.90	30.88	29.86	28.84	33.00	53.00
1.18	#16	22.55	21.35	20.71	20.07	19.43	18.79	21.00	40.00
0.60	#30	16.35	15.82	15.37	14.91	14.46	14.01	14.00	30.00
0.30	#50	12.32	12.23	11.90	11.57	11.24	10.91	9.00	22.00
0.15	#100	9.48	9.68	9.43	9.19	8.94	8.70	6.00	15.00
0.08	#200	7.01	7.46	7.30	7.14	6.97	6.81	4.00	9.00

Marshall stability recapitulation for all samples_

NO.	Asphalt Content [%]	Sample NO.	Datum		Grad. A		Grad. B		Grad. C		Grad. D		Grad. E
NO.	Asphalt Content [%]	Sample NO.	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT	ASPHALT PEN 60/70	RUBBER ASPHALT
1	5	SP 1	1,067.52	1,663.30	960,77	1,168.80	1,369.98	1,438.53	1,565.70	1,281.19	1,303,67	921.56	966,51	1,101.37
		SP 2	1,156.48	1,550.91	1,049.73	1,123.85	1,405.57	1,303.67	1,387.78	1,011.47	1,371.1	1,011.47	1,101.37	1,505.96
		SP 3	1,103.10	1,753.21	1,120.90	1,191.28	1,298.82	1,168.80	1,530.11	1,101.37	1,258.71	1,168.8	1,213.76	1,078.9
		SP 4	1,123.85	1,685.78	1,393.57	1,146.33	1,461.01	1,258.71	966.51	1,078.90	1,146.33	1,101.37	1,258.71	1,303.67
		SP 5	1,101.37	1,528.44	1,438.53	1,168.80	1,483.48	1,213.76	1,236.24	1,056.42	1,146.33	1,236.24	1,258.71	1,146.33
		Avg	1,110.46	1,636.33	1,192.70	1,159.81	1,403.77	1,276.69	1,337.27	1,105.87	1,245.23	1,087.89	1,159.81	1,227.24
2	5.5	SP 1	1,174.27	1,618.34	1,192.06	966.51	1,209.86	1,056.42	1,512.32	1,056.42	1,483.48	1,213.76	1,168.8	1,146.33
		SP 2	1,281.02	1,640.82	1,281.02	1,146.33	1,281.02	1,056.42	1,405.57	1,101.37	1,438.53	1,146.33	1,101.37	1,258.71
		SP 3	1,209.86	1,573.39	1,263.23	1,101.37	1,263.23	1,078.90	1,227.65	1,056.42	1,146.33	1,191.28	1,056.42	1,101.37
		SP 4	1,213.76	1,685.78	1,348.62	1,101.37	1,258.71	1,146.33	1,303.67	1,123.85	1,371.1	1,213.76	1,056.42	1,258.71
		SP 5	1,258.71	1,573.39	1,348.62	1,258.71	1,281.19	1,123.85	1,213.76	1,191.28	1,326.14	1,326.14	1,146.33	1,213.76
		Avg	1,227.52	1,618.34	1,286.71	1,114.86	1,258.80	1,092.38	1,332.59	1,105.87	1,353.12	1,218.25	1,105.87	1,195.78
3	6	SP 1	1,156.48	1,528.44	1,209.86	1,281.19	1,405.57	1,483.48	1,334.40	1,056.42	1,281.19	1,056.42	1,168.8	1,123.85
		SP 2	1,192.06	1,483.48	1,369.98	1,213.76	1,192.06	1,213.76	1,369.98	1,056.42	1,168.8	1,101.37	1,191.28	1,168.8
		SP 3	1,245.44	1,685.78	1,316.61	1,191.28	1,281.02	944.03	1,334.40	1,123.85	1,078.9	1,056.42	1,101.37	1,123.85
		SP 4	1,213.76	1,640.82	1,438.53	1,213.76	1,303.67	1,168.80	1,078.90	1,101.37	1,168.8	1,146.33	1,281.19	1,078.9
		SP 5	1,236.25	1,528.44	1,393.57	1,191.28	1,236.24	1,078.90	1,191.28	1,168.80	1,326.14	1,123.85	1,236.24	966.51
		Avg	1,208.80	1,573.39	1,345.71	1,218.25	1,283.71	1,177.79	1,261.79	1,101.37	1,204.77	1,096.88	1,195.78	1,092.38
4	6.5	SP 1	1,245.44	1,640.82	1,405.57	1,168.80	1,103.10	1,101.37	1,352.19	1,056.42	1,033.94	1,078.9	1,258.71	1,011.47
		SP 2	1,192.06	1,663.30	1,298.82	1,258.71	1,263.23	1,078.90	1,227.65	1,191.28	1,123.85	1,101.37	1,123.85	1,168.8
		SP 3	1,227.65	1,595.87	1,369.98	1,191.28	1,174.27	1,213.76	1,334.40	944.03	1,146.33	1,191.28	1,191.28	966.51
		SP 4	1,191.28	1,685.78	1,393.57	1,168.80	1,258.71	1,146.33	1,123.85	1,146.33	1,281.19	1,123.85	1,303.67	921.56
		SP 5	1,236.24	1,753.21	1,168.80	1,213.76	1,303.67	1,236.24	1,213.76	1,123.85	1,416.05	1,213.76	1,236.24	1,078.9
		Avg	1,218.53	1,667.79	1,327.35	1,200.27	1,220.60	1,155.32	1,250.37	1,092.38	1,200.27	1,141.83	1,222.75	1,029.45
5	7	SP 1	1,281.02	1,461.01	1,352.19	1,281.19	1,334.40	1,123.85	1,174.27	1,056.42	1,393.57	1,123.85	1,191.28	966.51
		SP 2	1,209.86	1,528.44	1,227.65	1,146.33	1,209.86	1,191.28	1,263.23	1,123.85	1,326.14	1,168.8	1,123.85	1,033.94
		SP 3	1,263.23	1,685.78	1,298.82	1,213.76	1,405.57	1,078.90	1,334.40	1,348.62	1,191.28	1,146.33	1,191.28	1,056.42
		SP 4	1,258.71	1,550.91	1,573.39	1,281.19	1,416.05	1,213.76	1,056.42	1,213.76	1,078.9	1,123.85	1,056.42	1,416.05
		SP 5	1,236.24	1,595.87	1.550.91	1,303.67	1,146.33	1,191.28	1,303.67	1,146.33	1,281.19	1,078.9	1,078.9	1,123.85
		Avg	1,249.81	1,564.40	1.400.59	1,245.23	1,302.44	1,159.81	1,226.40	1,177.79	1,254.22	1,128.35	1,128.35	1,119.35

Resilient Modulus (MR) values for two types of aggregate gradations_

No.	Aggregate proportion type	Sample (SP) No	Resilient modulus [MPa]
No.	Aggregate proportion type	Sample (SP) No	Pulse-1	Pulse-2	Pulse-3	Pulse-4	Pulse-5	Average
1.	Gradation specification (Datum), content 6.5%	SP-1	4,217	3,893	3,814	3,829	3,702	3,891
		SP-2	3,755	3,720	3,669	3,676	3,541	3,672
		SP-3	2,974	2,736	2,728	2,746	2,653	2,767
		SP-4	3,167	3,130	3,025	3,095	2,991	3,082
		SP-5	3,617	3,444	3,362	3,281	3,381	3,417
2.	Gradation B, asphalt content 6.5%	SP-1	2,708	2,683	2,596	2,547	2,540	2,615
		SP-2	2,283	2,197	2,154	2,138	2,120	2,178
		SP-3	2,798	2,749	2,623	2,613	2,591	2,675
		SP-4	2,332	2,252	2,191	2,157	2,143	2,215
		SP-5	2,627	2,483	2,420	2,410	2,408	2,470
3.	2017 MDP requirement		1,100

Summary of key performance metrics for optimal mix (Gradation B, 6_5% rubber asphalt)_

Parameter	Value	Standard Criteria	Performance Interpretation
Marshall stability (kg)	1,155	>800	High strength
Flow (mm)	3.38	2.0 – 4.0	Flexible, within limits
Marshall quotient (kg/mm)	341.81	>250	Excellent stiffness–flexibility ratio
Wheel tracking – Do (mm)	1.94	<4.0	Outstanding rutting resistance
Wheel tracking – DS (passes/mm)	2,975	>2,000	High deformation strength
Resilient Modulus (Mr, MPa)	>2,600	>1,100 (MDP 2017)	Sufficient structural stiffness

Wheel tracking test results of rubberised asphalt mixtures_

Gradation	Asphalt content [%]	Do [mm]	DS [passes/mm]	RD [mm/min]
Datum	6.5	2.71	2,803	0.0151
Gradation B	6.5	1.94	2,975	0.0141

The 7% natural rubber asphalt (SIR-20) properties_

No.	Type of test	Modified asphalt specification	Unit	Test results
				Laboratory of BBPJN North Sumatra							Laboratory of BPJN West Sumatra
				06-Sep-21	04-Jan-22	10-Jan-22	15-Jan-22	17-Jan-22	22-Jan-22	27-Jan-22	22-Jun-22
1	Penetration at 25°C (SNI 2456:2011)	Min. 50	0.1 mm	68.4	58	59	54.8	60.4	58.2	57	58.45
2	Softening point (SNI 2434:2011)	≥ 52	°C	52	53	54	53	53	52.5	52.5	52.5
3	Ductility at 25°C, 5 cm/min (SNI 2432:2011)	≥ 100	cm	140	151.5	153.5	154	152	153	149.5	> 140
4	Flash point (COC) (SNI 2433:2011)	≥ 232	°C	319	-	-	-	-	-	-	320
5	Specific gravity (SNI 2441:2011)	≥ 1.00	-	1.016	-	-	-	-	-	-	1.0164
6	Weight loss (SNI 2441:1991)	≤ 1.0	%	0.0002	-	-	-	-	-	-	0.0856
7	Solubility (AASHTO T-44-03)	≥ 99.0	%	99.66	-						-
8	Elastic recovery after pull (SNI 2866:2016)	≥ 30	%		34	33	35	32	35	31	-

Performance Evaluation of a New Aggregate Gradation for 7% Natural Rubber Modified Asphalt Mixtures

Figures & Tables

Fig. 1:

Fig. 2:

Volumetric Marshall result (VMA, VIM, VFB, Flow)_

Aggregate properties_

Five trial aggregate gradation_

Marshall stability recapitulation for all samples_

Resilient Modulus (MR) values for two types of aggregate gradations_

Summary of key performance metrics for optimal mix (Gradation B, 6_5% rubber asphalt)_

Wheel tracking test results of rubberised asphalt mixtures_

The 7% natural rubber asphalt (SIR-20) properties_

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