Evaluation of Reuse and Recycling Disaster Waste Materials for Post-disaster Shelter with Compressive Strength Testing and Case Study in Cianjur, Indonesia

Earthquake activity in Indonesia increases annually, causing more victims to require shelter and a rise in disaster waste. This waste can pose health risks and safety threats to humans, making careful management essential. One way to address this issue is recycling or reusing disaster waste materials to construct shelter. Therefore, this study aimed to investigate the performance of earthquake waste materials, recycled or reused as post-disaster shelter. To achieve this objective, a case study was conducted in Cianjur, Indonesia, where a recent earthquake occurred, and waste material samples (red brick, ceramic tile and roof tile) were collected for testing. Moreover, the compressive strength of the materials was measured in comparison with new building materials.  The results shows that ceramic tile and roof tiles meet the compressive strength standards and can be reuse for post-disaster shelters, with compressive strengths of 17.7 MPa and 21.8 MPa.

Compressive strength; Disaster waste material; Post-Disaster shelter

1.2. Related Studies

The United Nations Environment Programme (UNEP, 2008) defines disaster waste as accumulated construction debris and sediment from landslides caused by seismic activity. This waste poses health hazards due to the presence of chemical and biological contaminants, necessitating effective waste management. Managing natural disaster requires the implementation of effective policy, timely response, and appropriate preparedness measures (Berawi, 2018). Earthquake waste management practices vary across countries, but the Joint UNEP/OCHA Environment Unit outlines a guideline with three stages, namely emergency, early recovery, recovery, and contingency planning (MSB and JEU, 2011). According to (UNEP, 2008), in Indonesia, there are two stages in managing earthquake waste materials, namely pre-disaster and post-disaster. Pre-disaster focuses on mitigation measures, such as securing land leases or permits and developing programs to handle building debris effectively during emergencies. Meanwhile, post-disaster addresses recovery or reconstruction. It includes identifying waste at the disaster site, assessing its characteristics and capacity, evaluating risks, and determining priorities. Separating waste materials can increase the percentage of recyclable materials and raise public awareness (Kristanto, Gusniani, and Ratna, 2015). Disaster waste materials are categorized into plant debris, soil and sediment, domestic waste, and construction materials, such as bricks, wood, and concrete. Construction materials can be recycled or reused as aggregates or building materials for constructing shelter.

Shelter is essential for improving health, supporting families, ensuring security, providing protection from weather, and saving lives during crisis or post-disaster recovery (Sphere Association, 2018). Furthermore, it is defined as a place that offers comfort, access to clean water, and proximity to essential facilities including workplaces, educational institutions, and healthcare centers (UN/OCHA, 2008). Shelter can also be understood as a space equipped for human habitation (Sinclair, 2006). According to (Krimgold, Davis, and Thompson, 2015), and (IFRC, 2013), (Sinclair, 2006), post-disaster shelter includes transitional stages before victims move to permanent housing. These stages include emergency, temporary/transitional, and progressive/core shelter. Emergency shelter is a short-term solution that provides basic support immediately after a disaster. It is constructed using materials that can be quickly dismantled and reassembled, such as plastic sheets with wooden poles and ropes. Progressive/core shelter is designed with materials that allow for transformation into permanent housing. It typically includes one or two rooms and may also serve as transitional shelter when recovery efforts take longer.

According to  (PMI, 2019), (Krimgold, Davis, and Thompson, 2015), and (Wilson, 2011),  several criteria should be considered when reusing and recycling disaster waste materials for shelter, including security, comfort, long-term planning, and adherence to basic construction standards. Ensuring the quality of materials is crucial for constructing a shelter that is durable, environmentally friendly, affordable, and accepted by the local community. These objectives can be achieved by using high-quality materials, maintaining proper construction practices, and engaging experts and local communities. Shelter construction criteria are particularly relevant to this study, with a specific focus on the reuse and recycling of disaster waste. Furthermore, the strength of waste materials is a key consideration, specifically in disaster-prone areas where safety and durability are paramount.
      Several studies have investigated the reuse and recycling of disaster waste materials. For instance, (Al-Zaid, 2020), (Parura and Rahardyan, 2020), and (Sunoko, Prijotomo, and Noerwasito, 2016) examined disaster waste management techniques, structural methods, straw systems, beam systems, and manufacturing processes. Although these studies offered practical solutions for post-disaster shelter construction, there is no extensive testing of material properties to ensure quality. (Pradani et al., 2023) also investigated the recycling of disaster waste into flexible pavement materials such as aggregates, asphalt, and bitumen. Therefore, this current study aimed to evaluate the reuse and recycling of disaster waste materials through a case study in Cianjur, Indonesia, and material strength tests. Strength is defined as the maximum stress a material can withstand under an external force (load) without failure (Zhang, 2011). Strong materials resist deformation under high stress (ASM International, 2010). Strength is categorized into tensile, compressive, bending, and shear strength (Zhang, 2011). Due to resource limitations, this study focused on compressive strength, which is the ability of a material to withstand compressive forces without deforming (Betaubun and Hairulla, 2018). It is calculated using the formula:

Where F is the maximum load (in Newtons) and A is the total surface area (in mm²).

According to (Zhang, 2011), the strength of a material depends on its composition and structure. Even with the same composition, materials with different structures have varying strengths. Other factors include testing conditions, size, shape, surface characteristics, water content, loading speed, ambient temperature, and the accuracy of testing equipment. Therefore, materials are expected to meet specified standards, such as the Indonesian National Standard (SNI) or equivalent benchmarks, to be deemed suitable for use (BSN, 2019).

Case study and material testing were conducted to achieve the study objective. Case study was specifically conducted to examine the location, earthquake characteristics, building conditions in the affected area, the types and quantities of remaining earthquake waste materials, and the state of temporary housing structures at the site. Meanwhile, material testing included selecting samples for examination, identifying new materials for comparison, adjusting sample sizes for testing, and conducting compressive strength tests (Figure 1).

Figure 1 Workflow of the study

      Data collection for material measurement and testing was carried out using specific tools, including a meter for measuring dimensions and a compressive test machine for determining compressive strength values (Table 1).

Table 1 Measurement Framework

2.1. Case Study

        The case study location was the earthquake epicenter in Cianjur, specifically Sarampad Village, Cugenang District, Cianjur Regency, West Java. This region was highly earthquake-prone, with an MMI scale greater than VIII, showing the potential for ground cracks, slope movement, and land shifts (PVMBG, 2014). The earthquake occurred on November 21, 2022, with a magnitude of 5.6 and a damage intensity of VIII on MMI scale (Putratama, 2022). After a year of recovery, various facilities were constructed in the affected area. This site currently includes a nearby post and a 3,546.82 m² landfill designated for disaster waste disposal (Figure 2). Other facilities, such as schools and mosques, had also been established. The earthquake caused significant damage and loss of life. According to (Asmarini, 2022), 268 people died, 1,083 were injured, and 58,362 were displaced due to structural damage. Moreover, the destruction spanned three regions and sub districts, with 21,282 houses damaged, including 6,570 suffering severe destruction. To aid disaster victims, several shelters, mosque facilities, and schools have been rebuilt. Recycle House Program (RHP), led by Mr. Sunaryo Adhiatmoko, was selected as the focus of this case study. The program conceptualized house reconstruction post-earthquake using recycled materials (Figure 3).

Figure 2 Landfill for disposing disaster waste

Figure 3 Recycle House in Sarampad Village

       RHP had constructed 352 units in the disaster-affected area. These structures used coconut wood sourced from West Sumatra, bamboo walls made by craftsmen, spandex roofs, GRC list planks, and brick walls (Figure 4). Disaster waste materials, such as wood and concrete shards, were also repurposed for doors, window frames, brick walls, and foundations. In total, 3,546.82 m² of disaster waste was collected in an open field, forming a pile approximately 1 meter high. This abundance of waste prompted the village community to reuse 50% of the discarded materials for home reconstruction. Table 2 and Figure 5 present the types of disaster waste materials found and utilized in the case study.

Figure 4 Exploded Axonometric of Recycle House Program Materials Component

        Table 2 provides an overview of disaster waste materials that can be repurposed for shelter based on case study and theoretical investigations. Meanwhile, Figure 5 presents the practical application of these materials in RHP case study. Examples include mixed ceramic shards and bricks used for walls, repurposed wooden window and door frames, and reused roof tiles. Based on the types of materials identified at the site, specific waste materials were selected for testing. The selection process considered the application in RHP, use in residents' houses incorporating disaster waste, the availability of comparative materials, and the accessibility of testing equipment. The selected materials for testing included red bricks, roof tiles, and ceramic tiles.

Table 2 Comparison of Waste Material Application at Location and Theoretical Study

Material Type	Source
	(PMI, 2019)	(MSB and JEU, 2011)	(UNEP, 2008)	RHP shelter Case Study
Vegetation	-	As compost	-	Vegetation
Wood	Reused as construction	Reused as furniture or fuel for cooking	Reused as construction	Reused as window frame
Bricks	Reused as construction	Reused as walls	Bricks	Reused as construction
Concrete	-	-	-	Reused as walls or foundation
Plastic	-	Sorted and sold. Cannot be reused	Recycle	Collected and transferred
Sand & Gravel	As aggregate
Roof tile	Reused as roof	-	-	Reused as roof
Steel	Reused as joints	Recycle as metal strap	Cannot be reused. Not friendly to victims	Steel
PVC pipe	Reused as water Pipes	-	-	-
Glass	-	Recycled		-
Alumunium	-	-	Recycled
Ceramic tile	-	-	Reused as construction	Reused as floor tiles

*Note: - not mentioned