Effect of Concrete Materials on Fracture Performance

paper investigates the effect some nuxmg parameters and components characteristics on the fracture energy Gf and fracture toughness of concrete. Gf Kc concrete decrease with increasing 1 of coarse aggregate, rise water/cement ratio, affected greatly by Dmax addition of coarse aggregate to cement paste with lower W IC, increase gradually increasing volume content coarse aggregate. influence of ratio on Gf is not obvious. 1 Raw Materials 1. Cement: #525 portland cement. Coarse aggregate: crushed gravel, Dmax =30 mm, qualified grading, spe- cific gravity 2.65, bulk density 1450 kg/m3. 3. Fine aggregate: river sand, qualified grading, specific gravity 2.65, density 1450 kg/m3. Naphthalene superplasticizer Brand 5. Potable water. 119 2 ":""·00C' of water/cement ratio, maximum aggregate size Dmax, content of coarse aggregate on in this paper. I. 1: Influence water/cement ratio on concrete. Concrete mixtures and 28d compressive strengths are listed in Table 1. Series 2: Influence coarse aggregate on fracture performance concrete (Table 2) 3. · 3: Influence concrete 3) coarse aggregate on 1. Mixing proportion and 28d compressive strength of concrete No. W/C Cement Water Sand Gravel NF Compressive (kg/m3) (kg!m3) (kg!m3) (kg!m3) (kg!m3) (kg/m3) strength 1 0.25 740 185 526 1119 7.4 81.6 2 0.30 617 185 566 1202 6.2 85.3 3 0.40 463 185 615 .1307 ------ 78.7 4 0.50 370 185 645 1370 ------ 70.5 5 0.60 303 185 665 1412 ------ 58.0 Mixing proportion 28d compressive strength concrete aggregate grain No. D W/C Cement Water Sand Gravel Compressive (kg!m3) (kg!m3) (kg!m3) (kg!m3) strength (MPa) 1 5 - 10 0.40 463 185 615 1307 70. l 2 10 - 15 0.40 463 185 615 1307 72.4 3 15 - 20 0.40 463 185 615 1307 58.4 4 20- 25 0.40 463 185 615 1307 67.l 5 25 - 30 0.40 463 185 615 1307 69.