Why Concrete Hollow Blocks For Construction

Key Takeaways: Concrete hollow blocks meeting PNS ASTM C90/C129 standards provide 2,000+ psi compressive strength, 1-4 hour fire ratings, STC 45-50 acoustic performance, and natural thermal insulation. With 50+ year service life, local availability, and cost-effectiveness, CHB remains the optimal choice for Philippine residential and commercial construction.

Concrete hollow blocks (CHB), also known as concrete masonry units (CMU), have become the preferred construction material for residential and commercial buildings across the Philippines. This widespread adoption stems from a compelling combination of structural performance, cost-effectiveness, and versatility that meets the demands of modern Philippine construction.

Philippine Standards and Specifications

In 2019, the Department of Trade and Industry Bureau of Philippine Standards (DTI-BPS) adopted PNS ASTM C90:2019 and PNS ASTM C129:2019 as Philippine National Standards for loadbearing and nonloadbearing concrete masonry units, replacing the older PNS 16:1984 specification. These standards ensure CHB units meet minimum performance criteria for structural integrity and durability.

According to ASTM C90 specifications, loadbearing concrete masonry units must achieve a minimum net area compressive strength of 2,000 psi (13.8 MPa), increased from the historic 1,900 psi based on research by the National Concrete Masonry Association. The DPWH Standard Specification for Item 1046 - Masonry Works further establishes requirements for CHB use in public infrastructure projects.

Structural Performance and Seismic Resistance

The National Structural Code of the Philippines (NSCP) 2015 incorporates updated seismic provisions and performance-based design approaches for concrete masonry structures. When properly reinforced and grouted, CHB walls provide excellent load-bearing capacity and seismic resistance critical for Philippine construction along the Pacific Ring of Fire.

Concrete masonry walls must be anchored to all floors, roofs, and structural elements, with anchorage capable of resisting specified horizontal forces. In high seismic zones, the NSCP mandates specific reinforcement detailing and grout consolidation to ensure ductile behavior during earthquakes.

Fire Resistance and Safety

Testing according to ASTM E119 standards demonstrates that concrete hollow blocks provide exceptional fire resistance. A 150mm (6-inch) CHB wall achieves a 1-hour fire rating when unfilled, and up to 4 hours when solidly grouted. This non-combustible construction protects building occupants and meets National Building Code fire separation requirements for residential and commercial structures.

Acoustic Performance

Research published in technical literature shows that 150mm CHB walls achieve Sound Transmission Class (STC) ratings of 45-50, effectively blocking normal speech and ambient noise. Due to the mass and density of concrete masonry, CHB walls perform significantly better than lightweight partition systems, making them ideal for multi-family residential buildings, hotels, and commercial offices in urban areas.

Thermal Comfort and Energy Efficiency

Studies on concrete masonry thermal performance demonstrate that the hollow core design provides natural insulation while the thermal mass moderates temperature swings. This combination reduces air conditioning loads—a significant benefit in the Philippine tropical climate. Research shows thermal performance can be enhanced through insulation inserts, cavity wall construction, and reflective coatings.

Philippine Applications and Research

The National Housing Authority (NHA)) extensively uses CHB in public housing projects across the Philippines. Research conducted at Philippine universities has explored sustainable innovations, including eco-friendly CHB containing recycled materials and CHB with upcycled plastics as aggregate replacement, demonstrating the material's adaptability for sustainable construction.

A 2020 study on mortarless interlocking hollow blocks developed in the Philippines showed promising results for affordable, earthquake-resistant construction—particularly valuable for disaster reconstruction and low-cost housing programs.

International Innovation

Global research continues advancing CHB technology. An MDPI study from 2024 on thermal and mechanical enhancements achieved a 49.67% increase in thermal resistance through recycled materials. Malaysian researchers developed innovative interlocking systems for earthquake-resistant affordable housing, demonstrating CHB's continued evolution as a construction material.

Cost-Effectiveness and Practical Benefits

CHB masonry delivers superior cost-effectiveness through:

• •Fast installation: Modular 400mm × 200mm dimensions accelerate construction
• •Lower labor costs: Wide availability of skilled CHB masons throughout the Philippines
• •Minimal equipment needs: No formwork, shoring, or pumping required
• •Local manufacturing: Reduced transportation costs and delivery times
• •Long-term durability: 50+ year service life with minimal maintenance

Best Practices for Quality Construction

For optimal performance, construction teams should:

1. 1Verify material compliance: Use CHB meeting PNS ASTM C90/C129 standards
2. 2Follow DPWH specifications: Adhere to Item 1046 for masonry works
3. 3Ensure proper curing: Allow adequate curing time before installation
4. 4Detail reinforcement: Design per NSCP requirements for seismic zones
5. 5Quality control: Test mortar strength and verify block placement

Conclusion

Concrete hollow blocks remain the proven choice for Philippine construction due to their structural strength, fire resistance, acoustic performance, thermal efficiency, and cost-effectiveness. When manufactured to Philippine National Standards, designed according to NSCP requirements, and installed by skilled masons, CHB construction delivers reliable, durable buildings suited to Philippine conditions.

Allied Concrete Products, Inc., with over 60 years of manufacturing experience, provides high-quality concrete hollow blocks meeting all Philippine standards, backed by technical support and quality assurance testing for construction projects across Metro Manila, Laguna, and throughout the Philippines.

References

1. 1.Department of Trade and Industry Bureau of Philippine Standards. (2019). DTI-BPS adopts International Standards on masonry units. https://bps.dti.gov.ph/press-releases/23-2019/183-dti-bps-adopts-international-standards-on-masonry-units
2. 2.Concrete Masonry & Hardscapes Association. (2023). Concrete Masonry Unit Shapes, Sizes, Properties, and Specifications. https://www.masonryandhardscapes.org/resource/cmu-tec-001/
3. 3.National Structural Code of the Philippines (NSCP) 2015. Association of Structural Engineers of the Philippines. https://idecad.com/architecture-engineering-construction/building-design/nscp-2015/
4. 4.Concrete Masonry & Hardscapes Association. (n.d.). Fire Resistance Ratings of Concrete Masonry Assemblies. https://www.masonryandhardscapes.org/resource/tek-07-01d/
5. 5.Concrete Masonry & Hardscapes Association. (n.d.). Sound Transmission Class Ratings for Concrete Masonry Walls. https://www.masonryandhardscapes.org/resource/tek-13-01d/
6. 6.Ismaiel, M., Chen, Y., Cruz-Noguez, C., & Hagel, M. (2022). Thermal resistance of masonry walls: A literature review on influence factors, evaluation, and improvement. Journal of Building Performance Simulation, 15(2). https://journals.sagepub.com/doi/full/10.1177/17442591211009549
7. 7.Roa, M. J. L., et al. (2021). A non-disruptive ecological innovation on concrete block. Proceedings of the 11th Annual International Conference on Industrial Engineering and Operations Management. http://www.ieomsociety.org/singapore2021/papers/966.pdf
8. 8.Amparado, R. F., et al. (2020). Compressive strength and cost analysis of concrete hollow blocks with upcycled plastics as replacement for choker aggregates. International Journal of STEM Education Research, 4(3). https://iiari.org/wp-content/uploads/ijstem.v4.3.2341.pdf
9. 9.Mallari, E. N., et al. (2020). Mortarless interlocking hollow blocks: An innovation. International Journal of Emerging Trends in Engineering Research, 8(5). http://www.warse.org/IJETER/static/pdf/file/ijeter145872020.pdf
10. 10.Krause, M., et al. (2024). Enhancements in hollow block technology: Comprehensive thermal and mechanical characterizations. Energies, 17(23), 6133. https://www.mdpi.com/1996-1073/17/23/6133