Özet:

A Haitian general contractor and civil engineer was having difficulties achieving the target compressive strength in concrete mixes that are complaint with both regulations and regulations and client criteria. An experiment was conducted to assess the quality and performance of CINA cement and BASF PolyHeed 997 water-retarding admixtures commonly used in construction practice in Haiti. The results of this experiment demonstrated that the CINA cement product did not meet adequate compressive strength requirements and can be considered an inferior product when compared to cement manufactured in the United States (U.S.). On average, the compressive strength of final hardened cement was approximately 56% less where using Haitian derived cement in comparison to US-derived cement. Several tests were conducted to understand the impact of curing, cement content and the addition of admixtures to the compressive strength of the final product. Curing was shown to have a significant positive impact on the compressive strength. When the mixtures were subject to air curing only the Haitian-derived concrete did not reach the required target compression strength of 27.6 MPa despite the cement content from the original design was increasing by 50% and/or being exposed to a setting time of 56 days. The addition of admixture posed no negative effect on the concrete mixtures and did not act as a retarding agent. Significant increases in compressive strength observed for both the Haitian and US-derived mixes. No significant increases in compressive strength were observed from day 28 days 56. The overarching results of the research demonstrated that the most adequate solution for improving the existing quality of concrete mixtures containing Haitian-derived cement products is to increase the cement content to at least 30% by weight to achieve the designed compressive strength. It is recommended that the Haitian Government, concrete producers, cement manufacturers, and researchers combine their expertise, effort, and resources to produce appropriate solutions to improve the current condition of  concrete construction practices in Haiti to increase the robustness of infrastructure design to natural disasters such as hurricanes and earthquakes.

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