摘要:
A high early strength blended cement composition includes larger sized fly ash and/or natural pozzolan particles blended with smaller sized hydraulic cement particles containing tricalcium silicate and/or dicalcium silicate (e.g., Portland cement and/or ground granulated blast furnace slag). Excess calcium released from the hydraulic cement particles when mixed with water forms calcium hydroxide available for reaction with the fly ash and/or natural pozzolan. The fineness of the hydraulic cement particles is substantially greater than the fineness of the fly ash and/or natural pozzolan particles (e.g., about 1.25 to about 50 times greater). Reducing or eliminating coarse hydraulic cement particles that cannot fully hydrate but include unreacted cores reduces or eliminates wasted cement normally found in concrete. Replacing some or all of the coarse cement particles with coarse pozzolan particles provides a blended cement composition having significantly lower water demand compared to the hydraulic cement fraction by itself.
摘要:
Engineered cements are described that include an engineered clinker fraction designed for use with one or more supplementary cementitious material (“SCM”) fractions. The engineered clinker fraction has a narrow particle size distribution (“PSD”) with a relatively high tricalcium silicate (“C3S”) content as compared to traditional ordinary Portland cement (“OPC”). The high C3S content and narrow PSD provide desired reactivity and set time when combined with the one or more SCMs. The clinker fraction may be combined with one or more ultrafine SCM fractions and/or one or more coarser SCM fractions to achieve a desired wide particle size distribution. By engineering the chemistry and the particle size of the clinker fraction and the SCM fraction to work together, the engineered cements can have superior packing density, water demand, reactivity, set time, sulfate resistance, and strength development as compared to conventional OPC-SCM blends.
摘要:
The present disclosure relates to methods for controlling the chemical composition of a first pozzolan by blending it with a different pozzolan having a different chemical composition. The method includes intimately mixing the two pozzolans and using a chemical analyzer to determine a chemical characteristic of the pozzolan fraction being produced. The output from the chemical analyzer is then used to control the blending of the first and second outputs to maintain the chemical characteristic within a desired range.
摘要:
Hydraulic cements, such as Portland cements and other cements that include substantial quantities of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and/or tetracalcalcium alumino-ferrite (C4AF), are particle size optimized to have increased reactivity compared to cements of similar chemistry and/or decreased water demand compared to cements of similar fineness. Increasing hydraulic cement reactivity increases early strength development and release of reactive calcium hydroxide, both of which enhance SCM replacement and 1-28 day strengths compared to blends of conventional Portland cement and one or more SCMs, such as coal ash, slag or natural pozzolan. Decreasing the water demand can improve strength by decreasing the water-to-cement ratio for a given workability. The narrow PSD cements are well suited for making blended cements, including binary, ternary and quaternary blends.
摘要:
A high early strength pozzolan cement includes larger sized pozzolan particles blended with smaller sized hydraulic cement particles containing tricalcium silicate and/or dicalcium silicate (e.g., Portland cement). Excess calcium release from the hydraulic cement when mixed with water forms calcium hydroxide available for reaction with the pozzolan. The fineness of the hydraulic cement particles is substantially greater than the fineness of the pozzolan particles (e.g., about 1.25 to about 50 times greater). Reducing or eliminating coarse hydraulic cement particles that cannot fully hydrate but include unreacted cores reduces or eliminates wasted cement normally found in concrete. Replacing some or all of the coarse cement particles with pozzolan particles provides a pozzolan cement composition having significantly lower water demand compared to the hydraulic cement by itself.
摘要:
A high early strength blended cement composition includes larger sized fly ash and/or natural pozzolan particles blended with smaller sized hydraulic cement particles containing tricalcium silicate and/or dicalcium silicate (e.g., Portland cement and/or ground granulated blast furnace slag). Excess calcium released from the hydraulic cement particles when mixed with water forms calcium hydroxide available for reaction with the fly ash and/or natural pozzolan. The fineness of the hydraulic cement particles is substantially greater than the fineness of the fly ash and/or natural pozzolan particles (e.g., about 1.25 to about 50 times greater). Reducing or eliminating coarse hydraulic cement particles that cannot fully hydrate but include unreacted cores reduces or eliminates wasted cement normally found in concrete. Replacing some or all of the coarse cement particles with coarse pozzolan particles provides a blended cement composition having significantly lower water demand compared to the hydraulic cement fraction by itself.
摘要:
Hydraulic cements, such as Portland cements and other cements that include substantial quantities of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and/or tetracalcalcium alumino-ferrite (C4AF), are particle size optimized to have increased reactivity compared to cements of similar chemistry and/or decreased water demand compared to cements of similar fineness. Increasing hydraulic cement reactivity increases early strength development and release of reactive calcium hydroxide, both of which enhance SCM replacement and 1-28 day strengths compared to blends of conventional Portland cement and one or more SCMs, such as coal ash, slag or natural pozzolan. Decreasing the water demand can improve strength by decreasing the water-to-cement ratio for a given workability. The narrow PSD cements are well suited for making blended cements, including binary, ternary and quaternary blends.
摘要:
A high early strength pozzolan cement includes larger sized pozzolan particles and smaller sized hydraulic cement particles which contain tricalcium silicate (e.g., Portland cement). Particles larger than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) pozzolan particles, and particles smaller than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) hydraulic cement particles. Excess calcium from the hydraulic cement forms calcium hydroxide available for reaction with the pozzolan particles, optionally in combination with supplemental lime. At least 30%, 40%, 45%, 55%, 65% or 75% of the pozzolan cement (combined pozzolan and hydraulic cement particles) consists of pozzolan, and less than 70%, 60%, 55%, 45%, 35% or 25% consists of hydraulic cement.
摘要:
A high early strength pozzolan cement includes larger sized pozzolan particles and smaller sized hydraulic cement particles which contain tricalcium silicate (e.g., Portland cement). Particles larger than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) pozzolan particles, and particles smaller than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) hydraulic cement particles. Excess calcium from the hydraulic cement forms calcium hydroxide available for reaction with the pozzolan particles, optionally in combination with supplemental lime. At least 30%, 40%, 45%, 55%, 65% or 75% of the pozzolan cement (combined pozzolan and hydraulic cement particles) consists of pozzolan, and less than 70%, 60%, 55%, 45%, 35% or 25% consists of hydraulic cement.
摘要:
Hydraulic cements, such as Portland cements and other cements that include substantial quantities of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and/or tetracalcalcium alumino-ferrite (C4AF), are particle size optimized to have increased reactivity compared to cements of similar chemistry and/or decreased water demand compared to cements of similar fineness. Increasing hydraulic cement reactivity increases early strength development and release of reactive calcium hydroxide, both of which enhance SCM replacement and 1-28 day strengths compared to blends of conventional Portland cement and one or more SCMs, such as coal ash, slag or natural pozzolan. Decreasing the water demand can improve strength by decreasing the water-to-cement ratio for a given workability. The narrow PSD cements are well suited for making blended cements, including binary, ternary and quaternary blends.