Crushing Value Testing Service

Crushing Value Testing Service – Accredited ISO/IEC 17025 Aggregate Strength and Durability Assessment for the Colombian Market

The crushing value of aggregates is a fundamental mechanical property that measures the resistance of coarse aggregates to crushing under a gradually applied compressive load. This parameter is critical for ensuring the quality, strength, and durability of aggregates used in road construction, concrete production, railway ballast, and other civil engineering applications. A high crushing value indicates poor aggregate strength, which can lead to premature failure of pavements, concrete structures, and other load-bearing elements. In the Colombian market, where the Instituto Nacional de Vías (Invías), the Ministerio de Transporte, the Superintendencia de Industria y Comercio (SIC), and the Dirección de Impuestos y Aduanas Nacionales (DIAN) enforce strict quality standards for construction materials, the accurate determination of the aggregate crushing value is essential for product certification, supplier qualification, quality control in manufacturing, and import-export processes. Our laboratory offers a comprehensive crushing value testing service, applying standardized methods that measure the percentage of fines generated when a specified load is applied to the aggregate sample, following the requirements of NTC 4025, ASTM C131, BS 812, and the Invías specifications. All tests are performed under our ISO/IEC 17025 (CNAS) accreditation, and the resulting reports are fully accepted by Colombian authorities, making them indispensable for regulatory compliance, material selection, and market access in Colombia.

Aggregate Samples We Regularly Test

Our laboratory receives a wide variety of aggregate samples for crushing value testing. Typical samples include:

• Coarse aggregates for concrete and asphalt – crushed stone, gravel, and recycled aggregates.
• Railway ballast aggregates – for use in railway track construction.
• Aggregates for road base and sub-base – for pavement construction.
• Manufactured and crushed aggregates – from quarries and recycling operations.
• Prototype and new aggregate materials – submitted by manufacturers for validation of crushing resistance before production.
• Field-extracted aggregate samples – for quality control and conformity assessment.

Aggregate Crushing Value (ACV) Test – Standard Method

The aggregate crushing value (ACV) test is the most widely used method for determining the resistance of aggregates to crushing. It measures the percentage of fines (particles smaller than 2.36 mm) produced when a sample of aggregate is subjected to a specified load (400 kN) in a standard crushing cylinder. Our procedures follow the requirements of NTC 4025, BS 812-110, and Invías specifications (Artículo 510).

• Aggregate crushing value test (NTC 4025 / BS 812-110 – for coarse aggregates) – a sample of dry aggregates (passing the 14.0 mm sieve and retained on the 10.0 mm sieve) is placed in a standard steel cylinder (152 mm diameter). A plunger is inserted, and a load of 400 kN is applied at a uniform rate over a period of 10 minutes. The load is released, and the aggregate is sieved on a 2.36 mm sieve. The crushing value is calculated as the percentage of fines passing the 2.36 mm sieve relative to the total mass of the sample. We report the crushing value (in %) and the classification according to the requirements of the Invías specifications (e.g., a maximum ACV of 30 % for base course aggregates).
• Ten percent fines value (TFV) test (NTC 4025 – variant for determining the load required to produce 10 % fines) – for aggregates with a very low or very high crushing value, we perform the ten percent fines test, which determines the load (in kN) required to produce 10 % fines. This provides a more sensitive measure of the aggregate's strength, especially for soft aggregates. We report the TFV (in kN) and the classification.
• Aggregate impact value (AIV) test (BS 812-112 / NTC 4026 – for impact resistance) – although the AIV test measures impact resistance, it is often performed alongside the ACV test to provide a comprehensive assessment of aggregate toughness and strength. The test involves dropping a 14 kg hammer 15 times on the aggregate sample. We report the AIV (in %).
• Wet crushing value test (NTC 4027 – for aggregates in wet conditions) – the crushing value test is performed on aggregates that have been soaked in water for 24 hours, to evaluate the effect of moisture on the aggregate strength, which is relevant for applications in humid environments (common in many parts of Colombia). We report the wet crushing value.
• Crushing value at different temperatures (NTC 4028 – for aggregates in extreme climates) – the test is performed at a specified temperature (e.g., 0 °C, 40 °C) to evaluate the effect of temperature on the aggregate strength, which is relevant for aggregates used in pavements and concrete in the diverse climates of Colombia.

Los Angeles Abrasion Test – Measuring Resistance to Abrasion and Impact

The Los Angeles abrasion test is the standard method for evaluating the resistance of aggregates to abrasion and impact, which is a key indicator of their durability and their ability to withstand the forces of crushing and abrasion during service. This test is widely used for the quality control of aggregates for concrete and asphalt, and is required by the Invías and NTC standards.

• Los Angeles abrasion test (ASTM C131 / NTC 4020 – for coarse aggregates) – a sample of dried aggregates (graded according to the standard specification) is placed in the Los Angeles testing machine, along with a charge of steel balls. The machine is rotated at a speed of 30 to 33 rpm for 500 revolutions (or 1000 revolutions, depending on the requirement). The aggregate is then removed and sieved on a 1.70 mm sieve. The Los Angeles abrasion loss is calculated as the percentage of the sample passing the 1.70 mm sieve. We report the abrasion loss (in %) and the classification according to the Invías specifications (e.g., a maximum loss of 40 % for base course aggregates).
• Los Angeles abrasion test for railway ballast (ASTM C131 – adapted, NTC 4021) – for railway ballast aggregates, the test is performed with a different gradation and a specified number of revolutions (typically 500 or 1000 revolutions). The abrasion loss is reported, and the ballast is classified as compliant or non-compliant.
• Los Angeles abrasion test at different temperatures (NTC 4022 – thermal effect on abrasion) – the test is performed at a specified temperature (e.g., 0 °C, 40 °C) to evaluate the effect of temperature on the abrasion resistance, which is relevant for aggregates used in pavements in different climatic regions of Colombia.
• Los Angeles abrasion test with wet aggregates (NTC 4023 – for moisture effect) – the test is performed on aggregates that have been soaked in water for 24 hours, to evaluate the effect of moisture on the abrasion resistance, which is relevant for aggregates used in wet conditions.
• Micro-Deval abrasion test (ASTM D6928 / NTC 4024 – for fine aggregates and durability) – for fine aggregates and for a more sensitive measure of durability, we perform the Micro-Deval abrasion test, which uses a rotating cylinder with steel balls and water. We report the Micro-Deval abrasion loss (in %).

Unconfined Compressive Strength of Rock Aggregates – Evaluating the Strength of Intact Rock

For aggregates derived from rock sources, the unconfined compressive strength of the intact rock is an important parameter that correlates with the aggregate’s resistance to crushing and wear. This test is performed on intact rock cores (NQ‑size or similar) extracted from the aggregate source, and is required for the certification of quarries and for the design of pavements and concrete.

• Unconfined compressive strength (UCS) test (ASTM D7012 / ISO 14530 / NTC 4030 – for intact rock cores) – cylindrical rock cores (typically 50 mm to 100 mm diameter) with a length-to-diameter ratio of 2:1 are prepared and loaded in compression until failure. The compressive strength (in MPa) is calculated from the failure load and the cross-sectional area. We report the UCS (in MPa) and the failure mode.
• Point load strength index test (ASTM D5731 / NTC 4031 – for rock core and irregular lumps) – as a field or rapid test, we perform the point load strength test on rock cores or irregular lumps. The point load index (Is) is measured, and the UCS is estimated from the index using a correlation factor. We report the point load index and the estimated UCS.
• Slake durability test (ASTM D4644 / NTC 4032 – for weathering resistance) – for aggregates that may be exposed to wetting and drying cycles, we perform the slake durability test, which measures the percentage of material retained after a specified number of drying and wetting cycles. We report the slake durability index (Id).
• Soundness test (ASTM C88 / NTC 4033 – for freeze-thaw resistance) – for aggregates used in cold climates (e.g., high-altitude regions of Colombia), we perform the soundness test, which measures the resistance of the aggregate to disintegration by repeated cycles of immersion in a sodium sulfate or magnesium sulfate solution and drying. We report the loss (in %).
• Petrographic analysis (ASTM C295 / NTC 4034 – for identifying detrimental minerals) – we perform a petrographic examination of the rock to identify the mineral composition, the texture, and the presence of deleterious minerals (e.g., reactive silica, clay minerals) that could affect the aggregate's performance. We report the petrographic description and the potential for reactivity.

Particle Size Distribution and Gradation Analysis – Influence on Crushing and Abrasion

The particle size distribution (gradation) of the aggregate significantly influences its behavior during crushing and abrasion tests. Our gradation analysis provides a comprehensive understanding of the aggregate’s size composition and its compliance with the specifications for the intended application. This analysis is essential for the quality control of aggregate production and for the design of concrete and asphalt mixes.

• Sieve analysis (ASTM C136 / NTC 4040 – for coarse and fine aggregates) – a sample of dried aggregate is passed through a set of standard sieves (from 75 mm down to 75 μm). The mass retained on each sieve is weighed, and the cumulative percentage passing is calculated. We report the gradation curve and the fineness modulus (for fine aggregates).
• Gradation analysis for concrete aggregates (NTC 4041 – for fine and coarse aggregates) – the sieve analysis is performed according to the specific requirements of the concrete mix design. The gradation is compared against the requirements of the NTC 4041 and the Invías specifications.
• Gradation analysis for asphalt aggregates (NTC 4042 – for hot mix asphalt) – the sieve analysis is performed to determine the gradation of the aggregate for asphalt concrete. The gradation is compared against the specifications of the NTC 4042 and the Invías specifications.
• Flakiness and elongation index test (BS 812-105 / NTC 4043 – for shape classification) – we measure the flakiness and elongation indices of the coarse aggregates to evaluate their shape, which affects the compaction and the interlocking of the aggregate particles. We report the flakiness and elongation indices.
• Fines content and plasticity index (ASTM D4318 / NTC 4044 – for fine aggregates) – we measure the fines content (material passing the 75 μm sieve) and the plasticity index of the fine aggregates, to assess the quality and the workability of the aggregate. We report the fines content and the plasticity index.

Complementary Tests – Water Absorption, Specific Gravity, and Chemical Analysis

To provide a complete assessment of the aggregate quality and to correlate the crushing value and abrasion resistance with other physical properties, we perform a series of complementary tests, including water absorption, specific gravity, and chemical analysis. These tests are essential for the comprehensive certification of aggregates and for the selection of materials for long-lasting structures.

• Water absorption test (ASTM C127 / NTC 4050 – for coarse aggregates; ASTM C128 / NTC 4051 – for fine aggregates) – the sample is soaked in water for 24 hours, and the absorption is determined by measuring the mass of water absorbed. We report the water absorption (in %), which is a measure of the porosity of the aggregate.
• Specific gravity test (ASTM C127 / NTC 4052 – for coarse aggregates; ASTM C128 / NTC 4053 – for fine aggregates) – we measure the bulk specific gravity, the saturated surface-dry (SSD) specific gravity, and the apparent specific gravity of the aggregate. We report the specific gravity values.
• Chemical analysis of aggregates (ASTM C289 / NTC 4054 – for alkali-silica reactivity) – we perform the accelerated mortar bar test (or the chemical method) to determine the alkali-silica reactivity (ASR) of the aggregate, which is critical for avoiding concrete deterioration in the presence of alkalis. We report the ASR potential.
• Chloride and sulfate content (ASTM C1152 / NTC 4055 – for chloride content; ASTM C1580 / NTC 4056 – for sulfate content) – we measure the chloride and sulfate content of the aggregate, which are important for assessing the potential for corrosion of steel reinforcement and for sulfate attack. We report the concentrations (in %).
• Organic impurities test (ASTM C40 / NTC 4057 – for fine aggregates) – we perform the color test for organic impurities in fine aggregates, to detect the presence of organic matter that could affect the setting and hardening of cement. We report the color and the classification.

Test Report and Recognition in the Colombian Construction and Infrastructure Sector

All procedures described are within the scope of our ISO/IEC 17025 accreditation, with equipment calibrated periodically (crushing cylinders, Los Angeles machines, sieves, compression machines, etc.) and traceability to international standards (NIST, PTB). Our test reports are issued in Spanish and include:

• Full identification of the aggregate sample (source, type, size, grade, and manufacturer).
• Detailed description of the test methods applied (ASTM/BS/NTC/Invías standards, test conditions, and sample preparation).
• Numerical results: aggregate crushing value (%), Los Angeles abrasion loss (%), ten percent fines value (kN), unconfined compressive strength (MPa), water absorption (%), specific gravity, and gradation data.
• Graphical data: gradation curves and particle size distribution.
• Comparative tables against the values specified by the client or against the limits of the NTC 4025 (ACV), NTC 4020 (Los Angeles), NTC 4040 (Gradation), and the requirements of the Invías specifications (Artículo 510 for base courses, Artículo 520 for asphalt aggregates).
• Recommendations for the selection of aggregates, the optimization of the aggregate production process, and the quality control measures to achieve the required performance.
• Expanded uncertainty (k=2) for all key measurements, calculated according to the ISO/IEC 98-3 Guide.

These reports are fully accepted by the Instituto Nacional de Vías (Invías) for the approval of aggregates used in road and bridge projects, by the Ministerio de Transporte for the certification of materials, by the Superintendencia de Industria y Comercio (SIC) for product registration and quality certification, and by the Dirección de Impuestos y Aduanas Nacionales (DIAN) for tariff classification and quality verification in the import of aggregates and construction materials. Additionally, we offer consulting services for the selection of durable aggregates, the design of concrete and asphalt mixes, and the implementation of quality control programs for aggregate production, contributing to the safety, durability, and cost-effectiveness of infrastructure projects in the diverse and growing Colombian market, from the road networks and bridges of the Andean highlands to the ports and airports of the Caribbean coast.