# Enhancing Asphalt Binder Performance and Storage Stability with Trinidad Lake Asphalt (TLA)
## 1 Introduction  
Asphalt, commonly known as bitumen, has been utilized as a paving material for over a century. The primary form of asphalt used in today's industry is petroleum asphalt, a byproduct of crude oil refinement. Natural forms of asphalt also exist, such as lake asphalt, which is found in Trinidad and Venezuela, and rock asphalt, which is present in numerous regions globally. The pavement industry is the largest consumer of asphalt, accounting for over 70% of its total usage. Asphalt mixtures, when combined with aggregates, form a durable surface layer on roads, enhancing the comfort of transportation. Given its widespread use, selecting the appropriate type of asphalt for varying climatic conditions has garnered significant interest [1]. Another pressing issue is the increased load on road infrastructures due to the proliferation of electric vehicles (EVs), which are typically heavier than traditional combustion engine vehicles due to their substantial battery weight. This added stress is contributing to a decreased lifespan of pavements. Consequently, there has been a growing focus on enhancing the properties of conventional petroleum-based asphalt to extend pavement service life. Recent years have seen the advent of various modifiers to achieve this goal [2; 3; 4; 5]. Among these, Trinidad Lake Asphalt (TLA) is frequently used as an asphalt modifier. TLA is a semi-solid emulsion comprising soluble bitumen, mineral matter, and minor constituents. It is renowned for its consistent properties, high viscosity, density, superior rheological characteristics, and effective blending capabilities with other types of asphalt [6; 7; 8]. TLA also exhibits excellent temperature stability, chemical stability, and water stability, makingit highly compatible with petroleum asphalt due to their similar chemical compositions [9]. However, due to its hardness, TLA cannot be used alone in asphalt mixtures and is typically blended with petroleum-based asphalt in specified ratios. TLA can be incorporated into asphalt mixtures flexibly, without degradation or performance loss, even at elevated temperatures. It is especially prevalent in asphalt concrete (AC) and music asphalt (MA) pavements and has recently been applied in modern thin bridge pavement systems [10]. Research into the rheological properties of TLA-modified binders has shown that compatibility varies depending on the chemical components and colloid structures involved, leading to distinct performance outcomes [11; 12]. One of the most straightforward and commonly used methods to assess modified asphalt performance during production is the Superpave test method. This method is simple and provides clear results. Additionally, storage stability is another crucial criterion for modified asphalt, as mixing different materials can lead to phase separation [8; 13]. This study is motivated by the need to better understand how replacing traditional petroleum-based asphalt with TLA affects asphalt performance and stability. Specifically, we're looking to determine the best mix of TLA and a standard asphalt binder, PG 64-22, at different proportions: 10%, 20%, and 30%. We use a well-known testing approach called the Superpave method along with Multiple Stress Creep Recovery (MSCR) method to find out which mixture provides the best performance. In addition to performance, we are also concerned with how these mixtures hold up over time, especially at high temperatures. This is important because asphalt needs to be stable and perform well under the heat it experiences in real-world conditions. To assess this, we use another testing approach called the cigar tube test, which helps us understand the stability of these mixtures at elevated temperatures. The goal is to pinpoint the optimal amount of TLA that can be used to replace part of the petroleum-based binder without compromising the asphalt's quality and durability. This is crucial for ensuring that roads last longer and perform better.