Deep Purple and Rainbow Indicator

Deep Purple & Rainbow Carbonation Indicators Liquid pH indicators for measuring carbonation depth in field concrete How It Works When atmospheric CO₂ penetrates concrete, it reacts with calcium hydroxide in the cement paste to form calcium carbonate—a process called carbonation. This reaction lowers the concrete's alkalinity. Once the pH drops below 9, embedded steel becomes vulnerable to corrosion in the presence of moisture and oxygen. Measuring carbonation depth is essential for condition assessment and corrosion evaluation of reinforced concrete structures. Simple Application Spray the indicator onto a freshly broken concrete surface or newly cut core Allow to dry Read the color change against the included index to determine pH and carbonation front depth Applications Corrosion surveys — Identify the cause of reinforcement corrosion Service life estimation — Assess how far the carbonation front has penetrated Coating & sealer evaluation — Monitor the effectiveness of protective treatments or re-alkalization procedures Concrete strength estimation — Make rough assessments based on concrete age and relative humidity Products Model Description RI-7000 Deep Purple Indicator Set of 4 spray bottles, 80 ml each RI-8000 Rainbow Indicator Set of 4 spray bottles, 80 ml each Standards Conforms to BS EN 14630:2006 — Determination of carbonation depth in hardened concrete by the phenolphthalein method