THE REAL THREAT OF USING SUB-STANDARD CEMENT
Njombo Lekula, MD of PPC RSA, warns that sub-standard cement products are threatening the built environment industry and placing South African lives at risk. Use of sub-standard cement can negatively affect the sustainability of buildings and structures thereby leading to increased repair or maintenance costs, injuries and fatalities due to structural failures or collapse.
During a routine market surveillance exercise whereby competitors’ products were tested for comparison, PPC found that some products were sub-standard and warranted further investigation.
In an effort to protect the greater South African cement industry and consumers, PPC appointed Beton-Lab, a South African National Accreditation System (SANAS) accredited independent laboratory in September 2017 to physically purchase bags of cement in order to maintain the chain of custody and assure no interference from any outside party.
Photographs of each bag (front, side, back panels and bag weights) were taken to verify Letter of Authority (LOA) numbers, cement type and strength class. The weights of the bags were checked and EN strength testing in accordance with SANS 50197 for 2, 7 and 28 days was performed.
The South African Bureau of Standards (SABS) prescribed uncertainty of measurement allowance of 2.5% was applied when analysing the resultant data. The results showed an inability to produce a consistent quality product and thwarting of standards. Alan De Kock, MD of Beton-Lab says, “As an independent laboratory our work is tightly controlled, ensuring accurate data that is in no way influenced by outside parties.”
The report was recently released and the findings were shared with SABS and the National Regulator for Compulsory Specifications (NRCS), showing continued non-performance of the cements tested. According to Lekula, non-conformity of strength and weights of some products ranged from 11% to 73% of the sample set. “This failure to conform to local standards not only has an impact on the structural integrity of buildings, but also poses a threat to possible damage of property and even loss of life should the walls come tumbling down.”
It was also found that most of the sub-standard cement products carry the SABS mark. The SABS stamp is a mark of regulatory approval, instilling trust in the product being sold and, if used in accordance with the instructions, will result in a structure that is robust and safe.
Local cement producers have stringent internal quality regulations in place to ensure compliance of their products. However, with some producers supplying the market with sub-standard extended products, Lekula questions the long-term effect on the South African built environment as well as the sustainability and impact on our infrastructure. With non-compliance of quality and durability standards, consumers are unaware of the risk they face.
It takes up to 28 days for cement to develop strength and fly ash does not start developing strength before 28 days. The durability of mortar or concrete is primarily dictated by the amount and the strength performance of the cement that is used.
Retailers, builders and construction companies are also at risk of future legal action or loss of income as selling and using these sub-standard products can have a negative effect on the perception consumers have of their businesses and standards.
Lukela concludes, “The use of sub-standard cement products has been identified as one of the main causes of building collapse globally. PPC has decided to take a stand against sub-standard cement products to ensure the safety of consumers and longevity of structures.”
More information from www.ppc.co.za
