【单选题】75 / 80C25 混凝土,取σ=5.0 MPa\sigma=5.0\,\mathrm{MPa}σ=5.0MPa,配制强度fcu,0f_{cu,0}fcu,0约为?A25.0 MPa25.0\,\mathrm{MPa}25.0MPaB30.0 MPa30.0\,\mathrm{MPa}30.0MPaC33.2 MPa33.2\,\mathrm{MPa}33.2MPa正确D40.0 MPa40.0\,\mathrm{MPa}40.0MPa参考答案C参考解析25+1.645×5≈33.2 MPa25+1.645\times 5\approx 33.2\,\mathrm{MPa}25+1.645×5≈33.2MPa。