Influences　of　styrene-acrylate　(SA)　latexes　on　cement　hydration　were　investigated　by　isothermal　calorimetry　and　the　mechanism　wasdiscussed.　Super-retardation　phenomenon　caused　by　addition　of　SA　latexes　on　oil　well　cement　hydration　was　found　at　80　degrees　C　by　setting　time　measurement.　Quantitative　analysis　of　hydrolysis　of　SA　latexes　in　cementitious　systems　and　their　effect　on　cement　hydration　were　investigated　by　FTIR,　zeta　potential　and　surface　charge　density　measurements.　Results　show　that　the　hydrolysis　of　ester　groups　in　acrylate　units　is　significantly　accelerated　by　elevated　temperature　in　alkaline　condition.　The　continuous　production　of　carboxyl　groups　promotes　the　adsorption　of　polymer　particles　on　the　surface　of　cement　grains　and/or　leads　to　continuous　Ca2+　sequestration　from　pore　solution.　These　two　aspects　are　the　causes　of　the　super-retardation　effect.　It　is　concluded　that　unless　special　chemistry　is　involved　in　the　preparation　of　SA　latexes,　such　as　construction　of　core-shell　structure　of　the　colloidal　particles,　SA　latexes　with　high　content　of　acrylate　units,　due　to　the　severe　hydrolysis　of　the　ester　groups　in　the　polymer　chains,　are　not　recommended　to　be　used　in　oil　well　cement　system.　(C)　2016　Elsevier　B.V.　All　rights　reserved.