## 1 Introduction  
With commercial and industrial development occurring worldwide, energy consumption keeps rising. Current technology R&D focuses on developing solar energy as the \"next-generation energy\", but popularizing it in a short time is challenging. Due to global warming in recent years, an increasing problem is the reduction of energy consumption by air conditioning systems in buildings, among which improving air-cooling/heating facility power and building heat insulation has become an important topic [1]. The heat insulation, sound insulation, and fire resistance of the structure of the lightweight aggregate concrete (LWAC) building made of waste materials have been improved, proving its application potential in engineering, safety, and environment [2; 3; 4; 5]. Concrete building accounts for 90% of the total building in Taiwan at present, indicating that concrete is the most commonly used construction material. However, it is not recyclable or environmentally friendly; it poses threats to the living environment and energy conservancy, and thus its use goes against construction trends around the world [1]. Lightweight aggregate is advantageous due to its heat insulation, light mass, and fire resistance [6]; therefore, making use of appropriate material and taking advantage of material physical properties to maximize the thermal energy efficiency is a very important part of all engineering projects. Taiwan possesses the technology necessary to produce excellent quality lightweight aggregate from reservoir sediments through high-temperature sintering. Besides the engineering features offered by this technology, it can increase reservoir capacities, replenish natural sandstone resources, and elevate economic and ecologic values, thus contributing to the conservation of resources [7]. Cement is the most cost and energy-intensive component of concrete [8]. The characteristics of pozzolan ash historical mortar indicate that two types of volcanic ash have been used in the past: natural pozzolan ash (usually originated from volcanoes) and artificial pozzolan ash (such as ceramic powder) [9]. Partial substitution of pozzolan for cement can reduce cement consumption and lower carbon dioxide discharge. These factors are only indicators of pozzolan reactivity, and they cannot ensure that the lime/pozzolan mortar produced has the best potential performance. Therefore, some studies have shown that the consumption of Ca (OH) 2 in lime/pozzolan ash may be a reliable factor for evaluating pozzolan reactivity and detecting pozzolan products [10; 11; 12; 13]. Concrete made of copper slag can replace sand, thereby obtaining good mechanical properties, while also having environmental protection and technical advantages [14; 15]. Besides, many studies are also studying the use of auxiliary cementing materials, such as blast furnace slag, fly ash, silica fume, rice husk ash, and kaolin as calcined natural pozzolans to improve the performance of concrete, especially in combination with raw materials containing pozzolans, such as glass powder [16; 17; 18]. After adding 10%, 15%, and 20% of glass powder, the average compressive strength of concrete is 70.47, 72.01, and 73.31, respectively [19; 20; 21]. The average compressive strength values after adding 20%, 40%, and 60% copper slag to replace sand are 72.18, 74.38, and 73.08, respectively [22]. The average compressive strength values after adding 5% and 10% fly ash instead of cement are 71.56 and 73.22. After adding 5% and 10% silica fume instead of cement, the average compressive strength values are 72.33 and 73.53. After adding 5% and 10% rice husk ash instead of cement, the average compressive strength values are 72.86 and 69.49. Compared with glass concrete and copper slag high-strength concrete, the powder reaches the maximum strength under the 20% level of glass instead of cement [23; 24; 25; 26; 27].