Sieve analysis is a mechanical method in soil testing that determines the particle size distribution of a soil sample. This process involves passing the samples through sieves of standard sizes. The sieve sizes progressively become smaller from 125 mm all the way to 75 microns. Specific sizes and numbering of these sieves are:

To ensure quality and accuracy, a standard procedure is followed.

1. Sample Collection

The sample should be representative of site conditions and must be sufficient to ensure accuracy in the analysis.

2. Sieves

Standard sieves that meet specifications are stacked in ascending order of mesh size.

3. Sieving Process

The sample is placed on top of the sieve stack and is then shaken for a fixed duration. Shaking must have a pattern and should be uniform all throughout the process.

4. Weighing

After the sieving process, the sample retained on each sieve is measured by the difference between the final weight and the empty sieve weight. The weight of material in each sieve is recorded.

5. Particle Size Distribution

Using the recorded weight, the percentage of each size can be calculated. These percentages are then plotted with the sieve opening sizes on a particle size distribution curve.

This method is crucial in evaluating soil properties and its suitability for various engineering applications.

Rebar testing involves the examination and evaluation of reinforcing bars, commonly referred to as rebars, utilized in construction to provide tensile strength as reinforcement to reinforced concrete components like foundations, columns, beams, and walls. These rebars play a critical role in reinforcing the concrete and enhancing its overall structural integrity.

The primary objective of rebar testing is to ensure that the rebars utilized in construction projects meet the required quality and performance standards. To achieve this, a variety of non-destructive and destructive testing methods are applied to assess the rebars’ characteristics, including their dimensions, chemical composition, tensile strength, and adherence to pertinent standards and specifications.

The Rebar undergoes a series of tests for evaluation:

 1. Visual Inspection: Visual inspection is a critical step in rebar testing that involves carefully examining the surface of the rebars to identify any visible defects or irregularities. This includes checking for signs of excessive rust, corrosion, improper bending, or any other surface anomalies that may compromise the integrity of the rebars and the concrete structure they reinforce.

2. Chemical Analysis: Rebar samples undergo chemical analysis to determine their composition and verify the levels of essential elements, such as carbon and manganese. This test ensures that the rebars comply with material standards and specifications, as the correct chemical composition is crucial for their strength and durability.

3. Tensile Testing: Tensile strength tests are carried out on rebar samples to assess their ability to withstand tension without breaking. This test is of paramount importance as it evaluates the rebars’ capacity to resist forces and stresses within the reinforced concrete member, ensuring its load-carrying capability.

4. Bend Test: The bend test evaluates the rebar’s ductility by subjecting it to controlled bending. This helps assess the rebar’s ability to endure deformation without fracturing, which is essential for its flexural performance in the reinforced concrete structural members under various loading conditions.

Concrete compression testing is a fundamental test procedure for civil engineering and construction quality control and assurance used to evaluate the strength and quality of concrete. This procedure involves applying a compressive load to a cylindrical specimen until failure occurs. It is conducted in a controlled laboratory setting adhering to specific standards and protocols.

The results of concrete compression testing is focal in assessing the load-carrying capacity and structural performance of concrete in various construction applications, including buildings, bridges, pavements, and infrastructure projects. Structural and field engineers rely on these test outcomes to verify that the concrete meets the necessary strength and safety requirements.

Concrete testing generally follows a procedure that involves the following:

Sample Preparation:

Concrete specimens are cast in standardized molds, typically cylinders with a diameter of 150 mm (6 inches) and a height of 300 mm (12 inches). The specimens undergo careful compaction and curing under controlled conditions to achieve the desired strength.

Testing Apparatus:

The prepared concrete specimens are placed in a compression testing machine, which applies a progressively increasing load to the specimen. Equipped with load cells and a digital display, the machine accurately measures the applied force.

Loading Procedure:

The test commences with a pre-loading phase, during which a small load is applied to eliminate any irregularities or gaps between the specimen and the testing machine. Subsequently, the main loading phase ensues, gradually increasing the load at a specified rate until the concrete sample reaches failure.

Failure Criteria:
Failure of the concrete specimen is determined when it can no longer withstand the increasing load, causing the measured resistance to decrease. The maximum load the sample sustained before failure occurs is recorded as the compressive strength of the concrete.

An ISO-accredited materials testing laboratory is a lab that has received official certification for meeting the standards and requirements established by the International Organization for Standardization (ISO). ISO is an independent global organization that develops and publishes standards to ensure consistency, quality, and safety across various industries and sectors.

To obtain ISO accreditation, a materials testing laboratory undergoes a rigorous evaluation conducted by an independent accreditation body. The lab must demonstrate its competence, technical proficiency, and adherence to specific ISO standards relevant to its field of testing. The accreditation process involves a thorough assessment of the lab’s management system, equipment, staff qualifications, testing procedures, quality control measures, and data reporting practices.

Earning ISO accreditation is a significant accomplishment that validates the laboratory’s ability to produce precise and reliable test results. It provides assurance to clients, regulators, and other stakeholders that the lab operates with a high level of proficiency and complies with globally recognized standards. The ISO accreditation typically includes a defined scope, specifying the types of materials testing the lab is accredited to perform.

For materials testing laboratories, ISO/IEC 17025 is the standard commonly used for accreditation. This standard outlines the general requirements for the competence of testing and calibration laboratories and covers aspects such as staff qualifications, equipment calibration, testing methods, quality assurance, and results reporting. By obtaining ISO/IEC 17025 accreditation, materials testing laboratories demonstrate their dedication to providing accurate and dependable test data to support industries, engineering projects, construction, and research endeavors.

Philippine GeoAnalytics Inc is the first ISO-accredited testing laboratory in the Philippines and continues to provide testing services that are compliant with international standards. We strive and remain to be the trusted testing laboratory of choice.

Mechanically Stabilized Earth (MSE) walls and slopes are innovative solutions for ground stabilization and earth retention. At PGATECH Group, we offer cutting-edge MSE technologies designed to enhance the stability and durability of infrastructure projects. This article explores what MSE walls and slopes are, their history, purpose, advantages, applications, desirability, and the problems they address.

Mechanically Stabilized Earth (MSE) walls and slopes are structures that use layers of engineered materials to stabilize and retain soil. These systems typically consist of compacted backfill, reinforcing elements (such as geogrids or metal strips), and a facing material (such as concrete panels, blocks, or natural vegetation). MSE walls and slopes are designed to support heavy loads and prevent soil erosion, making them ideal for various construction projects.

The concept of MSE dates back to ancient times when natural materials were used to stabilize embankments. In the 1960s, innovative use of steel strips and compacted soil layers revolutionized earth retention techniques. Since then, advancements in materials and engineering practices have further refined MSE systems, making them a preferred choice for many infrastructure projects worldwide.

With production of stronger and better quality geosynthetics and its increase in use in the geoconstruction industry, MSEs reinforced with geosynthetics started being referred to as Geosynthetic Reinforced Soil (GRS) or Geosynthetically Confined Soil (GCS). This modern type of MSE Walls has proven to be a better choice because of its lightweight reinforcement that provides internal stability with more reliable, closer spacing between lifts.

The primary purpose of MSE walls and slopes is to provide effective soil stabilization and earth retention. Key functions include:

• Supporting Loads: MSE systems can support heavy structural loads, making them ideal for retaining walls, bridge abutments, and embankments.
• Preventing Erosion: The reinforced structure prevents soil erosion, maintaining the integrity of slopes and embankments.
• Improving Stability: Enhances the overall stability of the soil, reducing the risk of landslides and slope failures.
• Aesthetic Integration: MSE walls and slopes can be designed to blend seamlessly with the surrounding environment, providing both functional and aesthetic benefits.

MSE walls and slopes often replace or complement traditional earth retention methods such as:

• Gravity Retaining Walls: Concrete or masonry walls that rely on their mass to resist soil pressure.
• Cantilever Retaining Walls: Reinforced concrete walls that use a cantilevered design to stabilize soil.
• Gabion Walls: Structures made of wire baskets filled with rocks or other materials.
• Natural Slopes: Unreinforced slopes that may be susceptible to erosion and instability.

These traditional methods can be more expensive, labor-intensive, and less adaptable to various project conditions compared to MSE systems.

MSE walls and slopes offer numerous advantages, including:

• Cost-Effectiveness: Lower material and labor costs compared to traditional retaining walls.
• Speed of Construction: Faster installation process, reducing overall project timelines.
• Flexibility: Adaptable to a wide range of soil types and site conditions.
• Durability: Long-lasting performance with minimal maintenance requirements.
• Environmental Benefits: Can be designed with natural vegetation, promoting ecological sustainability.

MSE walls and slopes are applicable in various scenarios, such as:

• Highway and Railway Embankments: Providing stable support for transportation infrastructure.
• Bridge Abutments: Supporting bridge structures and connecting them to roadways.
• Retaining Walls: Stabilizing soil in residential, commercial, and industrial developments.
• Slope Stabilization: Reinforcing slopes to prevent landslides and erosion.
• Landscaping: Creating aesthetically pleasing and functional terraced landscapes.
• Flood Control: Constructing levees and floodwalls to manage water flow and prevent flooding.

The desirability of MSE walls and slopes stems from their:

• Efficiency: Rapid construction and effective soil stabilization.
• Economic Savings: Lower overall project costs due to reduced material and labor expenses.
• Minimal Disruption: Less invasive construction methods compared to traditional retaining walls.
• Versatility: Suitable for a variety of applications and environmental conditions.
• Aesthetic Appeal: Can be designed to blend with natural surroundings, enhancing visual appeal.

MSE walls and slopes effectively address several engineering challenges, including:

• Soil Instability: Reinforces weak soils to support structural loads and prevent failure.
• Erosion Control: Prevents soil erosion on slopes and embankments.
• Space Constraints: Provides effective earth retention in limited space, allowing for vertical construction.
• Load Support: Supports heavy loads in infrastructure projects such as highways and bridges.
• Environmental Impact: Reduces the need for extensive excavation and concrete usage, promoting sustainability.

Mechanically Stabilized Earth or MSE Walls are support systems that are used in construction projects to help control and support slopes or soil on inclines. This technology combines soil reinforcement and a facing system to provide support. MSE Walls are mostly used in highway and railway embankments, bridge abutments and other projects where soil slopes require stabilization/retention. MSE Walls are favored for their cost effectiveness and versatility in construction projects. An MSE Wall has 3 main components that help fulfill its purpose.

Reinforcement

One of the three main components is the reinforcement. The reinforcement can come in various forms such as steel strips or geogrids which are embedded within the soil mass creating a stable composite body. The reinforcement aids the wall in such a way that it distributes lateral forces and improves the overall strength of the wall.

The second component would be the backfill. To fill the space between the reinforcement layers, certain backfill types with known properties are used. This includes Granular Backfill, Cohesive Backfill, and reinforced soil

• • Granular Backfill

The granular backfill is the most common type of backfill used for MSE walls. It contains well graded and compacted granular materials that provides reliable interparticle friction resistance, and at the same time promotes interaction with the reinforcements.

• •  Cohesive Backfill

This type of backfill contains cohesive soils such as clay or silt. Cohesive backfill is rarely employed in situations where granular material is scarce. The strength from this backfill mainly comes from cohesion and internal shear strength of the material.

• • Reinforced Soil

Reinforced soils are fill materials mixed with reinforcing elements to upscale its shear strength and tensile properties. This type of backfill is only used in some cases where design specifications require higher strength.

Facing

The last component of the MSE wall is the facing. The facing is the front and visible surface of the MSE Wall. This component shields the wall from erosion. It also provides an aesthetic surface for the structure. Common facing techniques include: (a) wrap-around system which can be used to cultivate a vegetative face after several weeks; (b) gabions that are multipurpose and can be used with surfaces that are exposed to bodies of water; and (c) concrete panels used for vertical walls applications typical for abutments and other highway constructions.

At PGATECH Group, we are dedicated to providing state-of-the-art Mechanically Stabilized Earth (MSE) Wall – Geosynthetic Reinforced Soil (GRS) or Geosynthetically Confined Soil (GCS) – and slope solutions that ensure the stability and durability of your construction projects. Our expertise and advanced techniques enable us to tackle even the most challenging ground stabilization tasks, delivering reliable and cost-effective results. For more information about our MSE services, please contact us today.