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The study has been carried out to investigate the implementation of road preservation in the Indonesian National Road. The root of the problems of causes road deterioration are revealed, they consist of four aspects: planning and programming, implementation, maintenance, and operation of the road. The strength, weakness, opportunity and threat analysis were adopted to find the problem solution to overcome the challenges of road preservation in the Indonesian National Road. Some action programs to support the implementation of road preservation are suggested based on the results of strength, weakness, opportunity and threat analysis. In short term action, the government legislation, the technical guidance, the standard guideline and manual need to be provided shortly. Meanwhile, for medium term action, the “performance based contract” must be conducted effectively.

Tawangmangu-Sarangan highway is a national strategic road connecting two districts in two provinces; Karanganyar in Central Java and Magetan in East Java. The topography of the area is relatively high due to stiff hill and valley with the problematic geologic condition of weathered rock and silt sand. During rainy season, slope failures at some sections of this road were very often. The study to understand the cause of the failures is very important. Deep boring may have the best result to obtain soil parameter and stratigraphy of soil layer. However, this method was impossible due to the safety reason. The use of geophysic instrument such as geoelectric for the investigation combined with hand boring for soil sampling was a reasonable choice. Geoelecetric was utilized to predict soil layers properties and potential failure surface of the slope. This study was focused on the investigation on a slope failure location of Tawangmangu-Cemorosewu at Sta 4+600. Finite element software was utilized to understand the cause of previous failure and to model the most critical failure surface that may occurre in the future. Based on the modeling, the safety factor of the slope was 1.18 and 0.930 before and during construction. The condition of the slope after failure is still very critical due to the very low safety factor of 1.03 causing the potential of failure. It also recommended that geometrical method such as terrasering might be one of the solutions producing the safety fractor of 1.5.

Thin Hot Mixture Asphalt Concrete Overlays (THMACO’s) are comprised of a thin layer less than one inch hot mix asphalt concrete layer and a binder material/tack coat. The uses of thin layer are necessary to compromise with the environment issue especially to protect the natural resources and save the energy used during asphalt construction. THMACO’s can be used as preventative maintenance on pavement preservation or as a new surface on a pavementconstruction. This layeris usually regarded as non-structural layer at pavement design. However, this paper presents the structural assessment of this materials and their comparison to the conventional asphalt concrete mixtures. This research was conducted based on indirect tensile strength (ITS), unconfined compressive strength (UCS) and indirect tensile stiffness modulus (ITSM) of thin hot mixture asphalt. The results show that the thin hot mixture asphalt has performed slightly different on the Marshall and structural properties compare to conventional asphalt concrete.

Slurry Seal is an impermeable non-structural thin layer that is used for pavement maintenance consisting of a cold laid mixture of asphalt emulsion with continuous graded fine aggregate, mineral filler, water and other added ingredients. Ordinary Portland Cement (OPC) as the main filler in the application of slurry seal. Due to the relatively high cement prices and the pollution control for the environment; it is required to maintain the quality of the slurry by using a combination of OPC and LCFA (Low Calcium Fly Ash). This research was conducted to determine the value of consistency, setting time and indirect tensile strength (ITS) of slurry seal containing LCFA. A consistency testing used to obtain optimum moisture content to produce the sample for the rest of the test. The results show that with the addition of 5% water for pre-wetting and subsequently 10% of water content, the mixture provide appropriate consistency as required by highways standard. The time settings also meet the requirements of highways standard between 15 to 720 minutes for all types of mixtures. The mixture with composition of 50% OPC and 50% LCFA is considered as an ideal mixture at the optimum density value of 1.769 g/cm3, porosity of 9.55% and the indirect tensile strength of 30.99 kPa. It could be concluded that fly ash can be used as OPC partial replacement and enhance the properties on slurry seal application.

Overlay as the conventional method to maintain the surface quality of pavement need a large number of fresh natural aggregate and bitumen due to the relatively thick layer and consequently the road geometric must be corrected, so that regarded as not environmentally friendly. The alternative solution is Ultra-Thin Surfacing Hot Mix Asphalt (UTSHMA) which has a thickness of 12-15mm. UTSHMA gradation is designed based on the highest Marshall Quotient value tested by performing Marshall Test of five variations gradation from Standard Specification Construction of Transport Systems. The Optimum Bitumen Content (OBC) obtained by Marshall Test. The bitumen used for this is 60/70 penetration. The several structural tests were performed on the best gradation at OBC consist of Marshall tests, Indirect Tensile Strength (ITS), Unconfined compressive strength (UCS) tests and water permeability test. The UTSHMA mixture with coarse gradation has the greatest Marshall Quotient at 6.35% OBC accompanied by the higher ITS and UCS properties compare to conventional asphalt concrete. The coefficient permeability of UTSHMA is lower than conventional AC, indicated that UTSHMA is more resistant to water penetration. The research concluded that UTSHMA has compromised the standard specification and has sufficient structural properties compare to conventional AC and can be regarded as structural layer of pavement for overlay and road preservation design.

Road rehabilitation and reconstruction generate large supplies of reclaimed asphalt pavement (RAP). One of the efforts to reuse the RAP is by insitu process and utilize it as road base materials. To get satisfying result from the RAP, it is necessary to add a certain amount of Ordinary Portland Cement (OPC) as stabilizer. This study investigate the potential use of OPC-stabilized RAP in road bases. Laboratory experimental method was applied by using material collected from road located at Boyolali-Kartasura as the object of the study with the cement content variations of 4%, 5% and 6% for unconfined compressive strength test (UCS) and the cement contents variation of 5% and 6% for drying shrinkage test. The range of cement contents required for unconfined compressive strength of cement treated recycling base (CTRB) are 5% to 6%. The cement content used at Boyolali - Kartosuro road rehabilitation was 5.5%. Drying shrinkage during 28 days is 805.3 micro strain for the cement content of 5% and 826.3 micro strain for the cement content of 6%. The drying shrinkage of the materials was quite high for CTRB, so that carefully design and attention need to take into account to avoid the cracks at the road base and the prospective of reflective cracking at the surface course of the road.