The paper investigates the fundamental mechanical and durability properties of a M50 strength grade heavy weight concrete (HWC), with replacement of cement by fly ash at 15 %, 25 % and 35 % levels and slag at 40 %, 50 % and 60 % levels. The mechanical properties studied include compressive strength, elastic modulus, flexural and split tensile strengths, and the durability properties include water permeability, drying shrinkage and carbonation behavior. Although extended curing improves mechanical strength and water permeability properties of fly ash and slag blended HWCs, fly ash replacement reduces the modulus of elasticity of HWC to some extent. A simple relationship was used to estimate the elastic modulus of fly ash and slag based HWCs from their density and compressive strength, and the estimated values agreed well with the experimental results. Experimental investigation shows that the long term drying shrinkage strain for all fly ash based HWCs (15 %–35 %) is lesser than that for the 100 % ordinary portland cement (OPC) and all slag based HWCs. The resultant hardened density variations of fly ash and slag blended concretes exposed to long term controlled environment discussed in this paper can be used for estimating shielding thickness of HWC members against ionizing radiations. The carbonation resistance of fly ash and slag HWCs exposed to 3 % CO₂ condition for 146 days is also evaluated. Accelerated carbonation coefficients ($k_{acc})$ estimated for all types of HWCs show that the carbonation resistance of HWC prepared with 15 % fly ash and 40 % slag is comparable. The rate of accelerated carbonation of HWCs increases for the increase in replacement level of fly ash and slag. In addition to the higher rate of carbonation, increase in calcium carbonate content estimated through micro analytical studies also suggest that a higher level of slag replacement reduces the carbonation resistance of HWC significantly.

本文研究了 M50 强度等级重混凝土 (HWC) 的基本机械和耐久性能，其中粉煤灰含量为 15%、25% 和 35%，矿渣含量为 40%、50% 和 60%。 。研究的机械性能包括压缩强度、弹性模量、弯曲强度和劈裂拉伸强度，耐久性能包括透水性、干燥收缩率和碳化行为。虽然延长养护提高了粉煤灰和矿渣混合 HWC 的机械强度和透水性能，但粉煤灰替代在一定程度上降低了 HWC 的弹性模量。使用简单的关系式根据粉煤灰和矿渣基 HWC 的密度和抗压强度来估算其弹性模量，估算值与实验结果吻合良好。实验研究表明，所有粉煤灰基 HWC（15%–35%）的长期干燥收缩应变小于 100% 普通硅酸盐水泥 ( OPC) 和所有矿渣基 HWC。本文讨论的长期受控环境下暴露的粉煤灰和矿渣混合混凝土的硬化密度变化可用于估算 HWC 构件对电离辐射的屏蔽厚度。_{还评估了暴露于 3% CO 2}条件下 146 天的飞灰和矿渣 HWC 的抗碳化性。加速碳酸化系数（$k_{ACC}）$对所有类型的 HWC 的估计表明，用 15% 飞灰和 40% 矿渣制备的 HWC 的抗碳化性是相当的。HWCs的加速碳化速率随着粉煤灰和矿渣替代水平的增加而增加。除了较高的碳化率之外，通过微量分析研究估计的碳酸钙含量的增加也表明，较高水平的炉渣替代会显着降低HWC的抗碳化性。