Influence of Additives on Flexural Strength of Roller Compacted Concrete
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-08-21 |
| Journal | Journal of Cement Based Composites |
| Authors | Saad Issa Sarsam |
| Institutions | University of Baghdad |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Precision Material Preparation for Cement Composites
Section titled âTechnical Documentation & Analysis: Precision Material Preparation for Cement CompositesâExecutive Summary
Section titled âExecutive SummaryâThis research investigates the mechanical performance of Roller Compacted Concrete (RCC) when Portland cement is partially replaced by additives (Hydrated Lime, Fly Ash, Fumed Silica). The findings underscore the critical role of material composition and testing methodology in determining flexural strength.
- Core Finding: Hydrated lime and Fly Ash significantly enhance RCC flexural strength, with Hydrated Lime replacement yielding increases up to 109% in gap-graded mixtures.
- Methodological Insight: Flexural strength values are highly sensitive to the testing mode; four-point loading results were consistently 21% to 27% lower than three-point loading results.
- Precision Requirement: The study explicitly required the use of a diamond saw to extract precise beam specimens (38 x 10 x 8 cm) from the compacted slabs, demonstrating the necessity of ultra-hard, high-precision diamond tooling for accurate material characterization.
- Material Science Link: The successful replication and extension of this research depend on high-quality sample preparation, which relies on durable Polycrystalline Diamond (PCD) materials for cutting abrasive cementitious composites.
- 6CCVD Value Proposition: 6CCVD provides the necessary high-performance PCD and SCD materials, custom dimensions (up to 125mm), and precision laser cutting services essential for manufacturing the advanced tooling required in civil engineering material research.
Technical Specifications
Section titled âTechnical SpecificationsâThe following table summarizes key material and performance metrics extracted from the research paper, highlighting the precision required in sample preparation and testing.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Beam Specimen Dimensions | 38 x 10 x 8 | cm | Extracted using diamond saw (ASTM C78, C-293) |
| Fumed Silica Specific Surface Area | 170,000 - 230,000 | m2/kg | Extremely high surface area, contributing to water absorption |
| Hydrated Lime Specific Surface Area | 4404 | m2/kg | 13 folds higher than Portland cement |
| Flexural Strength Increase (Hydrated Lime, Gap Grade) | 109 | % | Maximum increase at 10% replacement (Three-point loading) |
| Flexural Strength Decrease (Fumed Silica, Dense Grade) | 77 | % | Maximum decrease at 10% replacement (Three-point loading) |
| Curing Temperature | 30 ± 2 | °C | Water bath curing for 27 days |
| Four-Point Loading Reduction Factor | 0.787 to 0.732 | Folds | Flexural strength reduction compared to three-point loading |
| Maximum PCD Wafer Size (6CCVD Capability) | 125 | mm | Available for high-performance tooling fabrication |
Key Methodologies
Section titled âKey MethodologiesâThe experimental procedure required stringent control over material composition, compaction, and precise sample extraction.
- Material Preparation: Type 1 Portland cement was partially replaced by Fly Ash, Fumed Silica, or Hydrated Lime at various percentages (e.g., 5%, 7%, 10% for Fumed Silica; 10%, 12%, 15% for Hydrated Lime).
- Mixture Proportioning: Concrete mixtures were prepared based on the modified Proctor standard (ASTM D-1557) to determine optimum moisture and density relationships.
- Sample Compaction: Slab samples (38 x 38 x 10 cm) were compacted using a roller compactor in three distinct stages (Primary, Breakdown, Final) with progressively increasing loads (up to 5.3 kg/cm width).
- Curing: Slabs were cured for 27 days in a water bath maintained at 30 ± 2°C.
- Precision Specimen Extraction: Beam specimens (38 x 10 x 8 cm) were precisely cut from the cured slabs using a diamond saw to ensure accurate geometry for flexural testing (ASTM C78, C-293).
- Flexural Testing: Specimens were tested using both three-point and four-point loading schemes to assess the influence of testing mode on measured flexural strength.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe requirement for precise sample extraction from highly abrasive cementitious composites necessitates the use of high-quality CVD diamond tooling. 6CCVD specializes in providing the foundational diamond materials required to manufacture these critical components, ensuring dimensional stability and longevity in demanding research environments.
| Research Requirement | 6CCVD Diamond Solution | Technical Specification & Advantage |
|---|---|---|
| Abrasive Cutting Tooling (Diamond Saw) | Industrial Grade Polycrystalline Diamond (PCD) | PCD offers extreme hardness and fracture toughness, ideal for manufacturing segments for saw blades used in cutting hard, abrasive materials like RCC. 6CCVD supplies PCD wafers up to 125mm diameter. |
| High-Precision Sample Geometry (38 x 10 x 8 cm beams) | Precision Laser Cutting Services | We offer in-house laser cutting and machining of diamond plates, ensuring that PCD tooling inserts or SCD components meet the tight dimensional tolerances required for ASTM-compliant specimen preparation. |
| Metrology & Sensor Protection (High-wear environments) | Single Crystal Diamond (SCD) Plates | SCD offers superior thermal conductivity and chemical inertness. It can be used for high-wear anvils, windows, or protective coatings for sensors monitoring temperature or strain during compaction and testing. |
| Custom Tool Integration | Custom Metalization Services | 6CCVD provides internal metalization (Au, Pt, Pd, Ti, W, Cu) on diamond surfaces, enabling robust bonding of diamond segments to tool bodies or integration of diamond components into complex testing rigs. |
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research, particularly focusing on the precision preparation of hard composite materials, 6CCVD recommends:
- Industrial Grade PCD: Essential for manufacturing durable, high-efficiency cutting tools (diamond saw blades) capable of processing large, abrasive concrete slabs.
- High-Purity SCD: Recommended for metrology applications, such as high-precision strain gauges or thermal management components used in the curing or testing apparatus.
Customization Potential
Section titled âCustomization PotentialâThe preparation of large specimens (38 cm length) requires robust tooling. 6CCVDâs capability to supply inch-size PCD wafers (up to 125mm) and substrates up to 10mm thick ensures that manufacturers of diamond cutting tools have access to the highest quality raw materials for large-diameter blades. Furthermore, our precision polishing capability (Ra < 5nm for inch-size PCD) ensures minimal friction and maximum tool life.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in the application of CVD diamond across extreme environments. We can assist engineers and scientists with material selection for similar composite material preparation and high-wear tooling projects, ensuring optimal diamond grade and geometry for maximum efficiency and precision.
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Roller compacted concrete is considered as a sustainable solution. In the present investigation, three types of additives namely (fly ash, fumed silica, and hydrated lime) are implemented as partial replacement of Portland cement for preparation of roller compacted concrete slab samples using dense and gap aggregate gradation. The slab samples were prepared at optimum cement requirement of 12 % and at (2 and 4) % cement below and above the optimum. Beam specimens of (38 x 10 x 8) Cm were extracted from the slab samples using diamond saw. The specimens were subjected to flexural strength determination using two testing modes, the three and the four points loading. It was noticed that the flexural strength under four-points loading mode is lower by a range of (0.787 to 0.732) folds than that under three-points loading mode for dense and gap graded mixtures respectively. It was concluded that the flexural strength increases by (96.2, 84, and 17.2) % and (109, 86, and 9.3) % after replacement of (10, 12, and 15) % of cement by hydrated lime while it declines by (50, 64.6, and 77) % and (0.1, 30.8, and 63.5) % after replacement of (5, 7, and 10) % of cement by fumed silica for dense and gap graded aggregates respectively. The flexural strength of dense graded mixtures increases by 63 % at 20 % replacement by fly ash, however, it increases by (99.7, 53.8, and 1.0) % after replacement of (10, 12, and 15) % of cement by fly ash for gap graded aggregates respectively.